BIOLOGY 

LIBRARY 

G 


THE 

DUBLIN  DISSECTOR. 

OR 

.MANUAL  OF  ANATOMY  ;* 

COMPRISING 

A  DESCRIPTION  OF  THE  BONES,  MUSCLES,  VESSELS, 
NERVES,  AND  VISCERA; 


THE  RELATIVE  ANATOMY  OF  THE  DIFFERENT  REGIONS 
OF  THE  HUMAN  BODY, 

TOGETHER  WITH 

THE  ELEMENTS  OF  PATHOLOGY. 


BY 

ROBERT  HARRISON,  A.M.  M.B.  T.C.D. 

MEMBER  OF,  AND  ONE    OF   THE  PROFESSORS  OF  ANATOMY  IN  THE  ROYAL  COLLEGE 

OF  SURGEONS  IN  IRELAND, 
AND  ONE  OF  THE  SURGEONS  OF  THE  CITY  OF  DUBLIN  HOSPITAL. 


SECOND  AMERICAN,  FROM  THE  FIFTH  ENLARGED  DUBLIN  EDITION. 

WITH  ADDITIONS  BY 

ROBERT  WATTS,  JR.  M.D. 

PROFESSOR  OF  ANATOMY  IN  THE  COLLEGE  OF   PHYSICIANS  AND   SURGEONS 
IN  THE  CITY  OF  NEW  YORK,  &C.  &C. 


NEW  YORK: 

J.  &  H.  G.  LANGLEY,  57  CHATHAM  STREET : 

PHILADELPHIA. HASWELL,  BARRINGTON  AND  HASWELL  ! 

BOSTON. WILLIAM   D.  TICKNOR. 


MDCCCXLIII. 


BIOLOGY 

LIBRARY 

G 


Entered,  according  to  Act  of  Congress,  in  the  year  1840, 

BY  J.  &  H.  G.  LANGLEY, 

in  the  Clerk's  Office  of  the  District  Court  of  the  Southern  District 
of  New  York. 


STEREOTYPED  BY  SMITH  AND  WRIGIFT,  216  WILLIAM  ST.  N.  Y. 

R.   CRAIGHEAD,  PRINTER,   112   rULTOK   ST. 


PREFACE. 


IN  undertaking  to  prepare  an  American  edition  of  the 
Dublin  Dissector,  the  editor  has  been  principally  actuated 
by  a  desire  to  aid  the  publishers  in  placing  within  the 
reach  of  the  medical  students  of  this  country,  a  work 
which  he  has  long  considered  the  best  manual  of  Practi- 
cal Anatomy  in  our  language.  It  was  suggested  by  the 
publishers,  that  some  additions  might  perhaps  be  made, 
which  would  enhance  the  value  of  the  book,  and  it  was 
left  to  the  editor  to  decide  what  those  additions  should  be  : 
it  should  be  distinctly  understood,  that  the  additions  are 
merely  compilations,  principally  from  J.  Cruveilhier,  (Ana- 
tomie  Descriptive,  Paris  1834):  Horner,  (Treatise  on 
Special  and  General  Anatomy,  Philadelphia  1836):  Tie- 
demann ;  and  Gross  on  Pathological  Anatomy,  (Boston 
1839):  and  that  nothing  can  be  claimed  on  the  score  of 
originality,  it  having  been  intended  to  select  those  facts 
which  are  of  the  most  practical  importance,  and  yet  not 
to  introduce  so  much  new  matter  as  to  diminish  the  con- 
venience of  the  book  as  a  dissecting  room  Manual. 

The  classification  of  the  muscles  has  been  introduced, 
because  in  the  performance  of  his  public  duties  the  editor 
has  found  something  of  the  same  kind  very  useful  in  im- 
pressing upon  the  minds  of  students  their  number,  situa- 
tion, and  functions  ;  the  only  muscles  omitted  in  the  clas- 
sification, are  those  of  ordinary  respiration,  and  those  of 
the  back,  which  are  left  as  classed  in  the  text,  in  which 
all  are  described  in  the  order  in  which  they  are  met  with 
on  dissection,  which  order  has  for  that  reason  been  left 
unchanged :  the  classification  cannot  be  considered  as 
original,  and  yet  it  would  be  difficult  to  give  credit  for  it. 
It  was  deemed  important  to  introduce  the  weights  and 
measurements  of  the  different  internal  organs,  and  to  give 
the  averages  as  nearly  as  possible,  both  in  reference  to 

* 


IV  PREFACE. 

their  normal  condition,  and  to  those  changes  in  size  and 
density  which  result  from  a  morbid  state.  It  also  seemed 
proper  in  such  a  work,  to  introduce  all  the  principal  varie- 
ties which  are  met  with  in  the  muscular,  arterial,  and 
venous  systems,  and  a  good  deal  of  pains  has  been  taken 
particularly  with  the  chapter  on  the  arteries  :  there  like- 
wise appeared  to  be  a  propriety  in  connecting  with  the 
description  of  each  bone  a  table  of  the  muscles  arising 
from,  and  inserted  into  it,  and  in  enumerating  the  fractures 
to  which  each  is  most  commonly  liable  ;  also  in  referring 
in  the  chapter  on  Articulations  to  those  luxations  not  enu- 
merated by  the  author  :  in  the  Appendix  a  few  additional 
directions  are  given  on  the  subject  of  injections  :  in  short, 
it  has  been  the  earnest  endeavour  of  the  editor  to  increase 
the  value  of  the  book  to  the  practical  student  of  anatomy. 
But  few  liberties  have  been  taken  with  the  text,  and  those 
principally  where  they  were  necessary  to  the  continuity 
of  sense  in  the  text  and  the  context ;  most  of  the  addi- 
tions are  distinguished  by  a  smaller  type,  and  all  of  them 
except  mere  verbal  alterations,  are  included  in  brackets  [] ; 
in  those  cases  where  it  seemed  proper,  reference  has 
been  made  to  anatomical  preparations  which  are  in  the 
College  Museum,  or  in  private  collections  in  this  city. 

It  is  needless  to  offer  any  apology  for  the  manner  in 
which  the  editorial  part  of  the  work  has  been  executed, 
as  its  merits  and  demerits  will  be  judged  of  by  the  proper 
tribunal :  the  editor  will  be  repaid  for  his  labour  should 
those  for  whose  benefit  it  has  been  undertaken  find  the 
book  not  less  useful  to  them,  with  the  additions,  than  it 
was  without  them,  to  himself  when  a  student. 

New  York,  8tk  October,  1840. 


CONTENTS. 

PART  I. 

OF  THE  MUSCLES,  VISCERA,  ETC. 
CHAPTER  I. 

ANATOMY  OF  THE  EXTERNAL  PARTS  OF  THE  HEAD 
AND  FACE. 

PAGE. 

EXTERNAL  PARTS  OF  THE  HEAD, 1 

General  remarks  on  muscles  of  head,  division  of, 2 

Classification  of  the  muscles  of  the  head  and  face, ib. 

Occipito-frontalis,  3 

Epicranial  aponeurosis, ib. 

Structure,  pathology,  &c.  of  scalp, 5 

External  muscles  of  ear,  6 

EXTERNAL  FARTS  OF  FACE, ib. 

Division  of  muscles  of, 8 

Orbicularis  palpebrarum,  ib, 

Physiology,  &c.  of  do -. 9 

Tensor  tarsi,  or  Homer's  muscle, 10 

Muscles  of  the  nose,  lips,  &c ib. 

Buccinator  muscle, 13 

Division  of  glands  in  general, 14 

Peculiarities  of  salivary  glands, 15 

Parotid  gland, 16 

Steno's  duct, 17 

Pathology  of  parotid  gland, 19 

Masseter,  temporal  and  pterygoid  muscles, ib. 

Temporal  aponeurosis, 21 

Motion  of  lower  jaw, ib. 

Vessels  and  nerves  of  face, 25 

CHAPTER  II. 

ANATOMY    OF   THE    NECK. 

Classification  of  the  muscles  of  the  neck, 27 

General  remarks  on  do , 31  — 


VI  CONTENTS. 

PAGE. 

Platysma,  myoids,  and  cervical  fascia, 32 

Sterno-cleido-mastoid  muscle, 34 

Division  of  neck  into  triangular  regions, 35 

Sterno-hyoid  and  thyroid  muscles, 36 

Omo-hyoid  muscle, 37 

Thyroid  body,  ib. 

Physiology  and  pathology  of, 38 

Digastric  muscle, 39 

Sub-maxillary  gland, 40 

Whartonian  duct, 42 

Pathology  of  sub-maxillary  gland, ib. 

Mylo-hyoid  and  genio-hyoid  muscles, ib. 

Sublingual  gland,  ib. 

Hyo  and  genio-hyo-glossi  muscles, ib. 

Styloid  muscles,  43 

Vessels  and  nerves  of  the  neck, 44 

MOUTH, 48 

Tongue, 49 

Pharynx,  constrictors  of ;  openings  in, 50 

Palate,  arches  of;  uvula, 54 

Levator  palati,  tensor  palati,  palato-glossus, 55 

Tonsils,  or  amygdalse,  ib. 

Pathology  of  soft  palate,  tonsils,  &c 56 

(Esophagus, ib. 

Pathology  of  pharynx  and  oesophagus, 57 

LARYNX,  cartilages,  muscles,  &c.  &c „ 58 

Vessels  and  nerves  of  larynx, 62 

Pathology  of  larynx  and  trachea, 63 

Deep  muscles  of  neck  ;  longus  colli,  &c 64 

CHAPTER  III. 

ANATOMY    OF    THE    THORAX. 

Muscles  on  anterior  and  lateral  parts  of  thorax, 66 

Mammary  gland, ib. 

Pathology  of, ib. 

Pectoralis  major,  &c.  &c 67 

Serratus  magnus, 69 

Intercostal  muscles, 70 

Levatores  costarum,  triangulars  sterni,  71 

AXILLA, 72 

CAVITY  OF  THE  THORAX, 73 

Mode  of  opening  thorax, 74 

Anterior  mediastinum,  ib. 

Pleura,  75 

Ligamentum  latum  pulmonis, 76 

Posterior  mediastinum, ib. 

Vena  azygos,  77 

Thoracic  duct,  &c 78 

LUNGS, 79 

^  Pathology  of  lungs  and  pleurae, 81 


CONTENTS.  Vll 

PAGE. 

Pericardium, 82 

Pathology  of, 83 

HEART, 84 

Pulmonary  artery, , 8 : : 87 

Ductus  arteriosus, ib. 

Aorta, , 89 

Description  of  the  heart, 90 

Pathology  of  heart, 91 

Parts  passing  through  upper  orifice  of  thorax, 92 

Trachea, « 93 

Bronchial  glands, ib. 


CHAPTER  IV. 

MUSCLES    ON    THE    POSTERIOR    PART    OF    THE    TRUNK. 

Muscles  of  the  back;  ligamentum  nuchae, 

Lumbar  fascia,  and  trapezius, 

Latissimus  dorsi,  97 

Rhomboideus, 98 

Levator  anguli  scapula  and  serrati  postici, 99 

Splenius, 100 

Sacro-lumbalis,  longissimus  dorsi,  and  spinalis  dorsi, ib. 

Cervicalis  descendens, 101 

Recti  and  obliqui  capitis  postici,.. 103 

CHAPTER  V. 

ANATOMY  OF  THE  UPPER  EXTREMITY. 

General  remarks  on  the  muscles  of  the  upper  extremity, 105 

Classification  of  do ib. 

Fascia  and  superficial  veins  of  the  arms, 110 

Deltoid  muscle, Ill 

Supra  and  infra-spinatus  muscles, 112 

Teres  minor  and  sub-scapula  muscles,  113 

Remarks  on  Capsular  muscles  of  the  shoulder  joint,  ib. 

Coraco-brachialis  muscle, 114 

Biceps,  115 

Brachialis  anticus,  or  externus, 116 

Triceps, 117 

Vessels  and  nerves  of  the  arm, 119 

Fore  arm  and  hand, 120 

Cutaneous  veins,  basilic,  cephalic,  median,  &c ib. 

Fascia  of  fore  arm, 121 

Palmar  fascia, ib. 

Palmaris  brevis  muscle,  ib. 

Division  of  muscles  of  fore  arm  into  pronators  and  flexors, .  122 

Supinators  and  extensors, 127 

Muscles  of  the  hand, 131 

Vessels  and  nerves  of  the  fore  arm  and  hand, 1. 


Till  CONTENTS. 

CHAPTER  VI. 

ANATOMY    OP    THE    ABDOMEN    AND    PELVIS. 

PAGE. 

Superficial  fascia  of  the  abdomen, 136 

*Obliquus  externus, 138 

Linea  alba, 139 

Linea  semilunaris,  and  linea  transversae,  140 

External  inguinal  ring,  and  intercolumnar  fascia, 141 

Poupart's  or  Fallopius's  ligament, ib. 

Gimbernaut's  ligament  and  triangular  ligament  or  fascia, 142 

Obliquus  internus  or  ascendens, 143 

Cremaster  muscle, 144 

Transversalis, 145 

Rectus  muscle, 146 

Pyramidal  muscle  and  transversalis  fascia, 147 

Spermatic  or  inguinal  canal,  148 

HERNIA, ib. 

Oblique  inguinal, ib. 

Direct  or  ventro-inguinal, 149 

Femoral  or  crural, 150 

Inguinal  lymphatic  ganglia, ib. 

Saphena  vein, 151 

Fascia  lata, ib. 

Fascia  iliaca, 153 

Femoral  or  crural  ring, 154 

Fascia  propria, ib. 

Measurements  of  parts  engaged  in  hernia,  156 

Regions  of  abdomen,  ib. 

Peritoneum,  157 

Omenta,  meso-colons,  &c 160 

Division  of  viscera  of  abdomen,  164 

Stomach,  ib. 

Glandulas  Brunneri, 166 

Duodenum,  167 

Jejunum,  ilium,  and  caecum,  or  caput  coli, 168 

Ilio-colic  valves, 169 

Colon  and  rectum, 170 

Structure  of  intestinal  canal, 171 

Glandulse  aggregates  or  Peyeri, 172 

Pathology  of  peritonaeum  and  abdominal  viscera, 173 

Gastro-enteric  mucous  membrane, 174 

Liver, 176 

Pathology  of, 180 

Gall  bladder, 181 

Pathology  of, ib. 

Spleen,  182 

Pathology  of, 183 

Pancreas,  ib. 

|f  Pathology  of, 184 


CONTENTS.  IX 

PAGE. 

Vessels  and  nerves  of  the  abdomen, 184 

Kidney, 187 

Ureter,  189 

Renal  capsule,  or  supra-renal  or  atrabiliary  body, 190 

Pathology  of  kidney, ib. 

Bladder, 208 

Pathology  of, 214 

Urethra, 226 

Diaphragm,  191 

Muscles  which  assist  in  respiration, 194 

Quadratus  lumborum  and  psoae  muscles, 195 

Iliac  muscles, 196 

PERINEUM  IN  THE  MALE, 197 

Sphincter  ani,  superficial  fascia, 198 

Erector  or  compressor  penis, 200 

Accelerator  urinae  or  ejacultaor  seminis,  &c.  &c ib. 

Tri  angular  ligament  of  urethra, 202 

Cowper's,  or  the  anti-prostatic  glands, ib. 

Levator  ani  muscle, 203 

Compressores  urethrse,  or  Wilson's  muscles, 204 

Surgical  anatomy  of  parts  concerned  in  lithotomy, 205 

Pubic  ligament, 206 

Coccygeus  muscle,  ib. 

Triangular  space  on  fundus  of  bladder, ib. 

Pelvic  portion  of  peritonaeum, 207 

Urinary  bladder, 208 

Pathology  of, 214 

Pelvic,  obturator,  and  vesical  fasciae,  209 

Ligaments  of  the  bladder,  210 

Coats  of  the  bladder 212 

ORGANS  OF  GENERATION  IN  THE  MALE, 215 

Scrotum, , , ib. 

Dartos,  superficial  fascia, 216 

Tunica  vaginalis,  albuginea,  217 

Testicle, , 218 

Epididymis, 219 

Vas  deferens, 220 

Spermatic  cord, 221 

Vesiculae  seminales, 222 

Prostate  gland, 223 

Penis, 224 

Urethra, 226 

Method  of  injecting  the  penis  and  corpus  spongiosum  ure- 
thrse,   228 

Pathology  of  testicle, 230 

Pathology  of  vesiculse  seminales  and  prostate  gland, 231 


X  CONTENTS. 

CHAPTER   VII. 

ORGANS    OF    GENERATION    IN    THE    FEMAL13. 

PAGE. 

Vagina,  uterus,  &.  &c 233 

Fallopian  tubes  and  ovaries,  236 

Pathology  of  female  organs  of  generation, 237 

CHAPTER  VIII. 

ANATOMY    OF    THE    INFERIOR    EXTREMITY. 

Classification  of  muscles  of  the  inferior  extremities,  238 

Fascia  lata, 243 

Muscles  on  the  forepart  and  sides  of  the  thigh,  245 

Tensor  vaginae  femoris,  sartorius,  triceps  adductor,  &c.  &c —  ib. 

Vessels  and  nerves  of  the  thigh, 252 

Muscles  on  the  posterior  part  of  the  thigh, 253 

Glutseus  maximus,  medius,  &c.  &c 254 

Pyriformis,  obturator  internus,  externus,  gemelli,  &c.  &c 256 

Glutceal  and  sciatic  vessels,  <$-c 259 

Sciatic  nerve, ib. 

Hamstring  muscles,  260 

Popliteal  space, ib. 

Leg  ;  fascia,  sub-cutaneous  veins  and  nerves, 264 

Plantar  fascia,  267 

Muscles  on  the  anterior  and  external  part  of  the  leg, ib. 

Anterior  tibial  vessels  and  nerves,  270 

Muscles  on  the  back  of  the  leg, 271 

Muscles  of  the  foot, 275 

Posterior  tibial  vessels  and  nerves, 281 


PART  II. 

OF  THE  NERVOUS  SYSTEM. 
CHAPTER  I. 

BRAIN,    MEDULLA    OB  LONG  ATA,    AND    ORIGIN    OF    THE 
CEREBRAL    NERVES. 

BRAIN, 282 

Dura  mater, 283 

Sinuses,  285 

Arachnoid  membrane,  pia  mater, 288 

Cerebrum, 290 


CONTENTS.  XI 

PAGE. 

Ventricles, „ 293 

Cerebellum, 299 

MEDULLA  OBLONGATA, 301 

ORIGIN  OF  THE  CEREBRAL  NERVES, 302 


CHAPTER  II. 

ANATOMY    OP    THE    MEDULLA    SPINALIS,  ETC. 

General  view  of  cranial  nerves, 306 

Origin  of  the  spinal  nerves, 307 

Dissection  of  the  brain  from  below, 311 

Structure  of  the  cerebellum, 312 

Structure  of  the  cerebrum,  ib. 

Vessels  of  the  brain, • 

Pathology  of  the  brain  and  its  membranes,  315 


CHAPTER  III. 

DISSECTION    OF    THE    CEREBRAL    SPINAL,    AND    GANGLI- 
ONIC    NERVES. 

Olfactory, 317 

Optic,  318 

Third  and  fourth, 319 

Ophthalmic  nerve, ib. 

Lachrymal,  frontal,  and  nasal  nerves,  320 

Sixth  or  abducens  nerve, 321 

Ophthalmic  or  lenticular  ganglion, ib. 

Offices  of  orbital  nerves,  322 

Superior  maxillary  nerve, 323 

Meckel's  ganglion, ib. 

Palatine,  spheno-palatine,  naso-palaline,  or  nerve  of  Cotunnius,  ib. 

Naso-palatine  ganglion,  ib. 

Vidian  nerve,  corda  tympani,  submaxillary  ganglion, ib. 

Inferior  maxillary  nerve, 325 

Inferior  dental  and  gustatory  nerves, 326 

Facial  nerve  or  portio  dura, 327 

Auditory  nerve  or  portio  mollis, 329 

Glosso-pharyngeal  nerve, ib. 

Pneumo-gastric  nerve, ib. 

Pharyngeal  plexus, 330 

Laryngeal  nerves,  ib. 

Pulmonic  plexuses,  331 

CEsophageal  plexus  or  plexus  gulee, 332 

Spinal  accessory  nerve, ib. 

Lingual  nerve,  ib. 

SPINAL  NERVES, 333 

Sub-occipital  nerve, ib. 


Xll  CONTENTS. 

PAGE. 

Cervical  plexus, 334 

Phrenic  or  internal  respiratory  nerve, ib. 

External  respiratory  nerve, 335 

Brachial  plexus, ib. 

Thoracic  and  scapular  branches, 336 

Internal  cutaneous,  external  cutaneous, ib. 

Median  or  brachial,  ulnar,  musculo-spiral,  &e 337 

Dorsal  nerves, 339 

Nerves  of  Wrisberg 340 

Lumbar  nerves  and  plexus, ib. 

Inguino-cutaneous,  anterior  crural  nerves, ib. 

Obturator,  glutaeal,  communicating,  &c 34J 

Sacral  nerves  and  plexus, 342 

Lesser  sciatic,  inferior  glutaeal,  pudic  nerves,  &c 343 

Great  sciatic  or  posterior  crural  nerve, ib. 

SYMPATHETIC  NERVES, 345 

Cervical  ganglions,  346 

Cavernous  or  carotid  ganglion, 347 

Cardiac  nerves, ib. 

Cardiac  plexus,  cardiac  ganglion, 348 

Thoracic  ganglions, , 349 

Splanchnic  nerves, ib. 

Solar  plexus, , 350 

Lumbar  glanglions, ib. 

Sacral  or  pelvic  ganglions, ; 351 

Ganglion  impar, , ib. 


CHAPTER  IV. 


ORGANS    OF    SENSE. 

Nose, 351 

Taste, 354 

Ear, 355 

General  view  of  muscles  of  the  ear, , ib. 

Eustachian  tube, 357 

Bones  of  the  ear, 358 

Muscles  of  the  ear, ib. 

Labyrinth,  359 

Eye, 360 

Muscles  of  the  orbit, ib. 

Lachrymal  apparatus, 363 

Eyelids, 364 

riorner's  muscle, ib. 

Globe  of  the  eye, 365 

Skin,  or  the  organ  of  touch,  371 

Cellular  membrane, 373 


CONTENTS.  Xlll 

PART  III. 

ANATOMY  OF  THE  VASCULAR  SYSTEM. 

FA6E. 

ARTERIAL  SYSTEM, 375 

Aorta, ib. 

Coronary  arteries, 376 

Arteria  innominata, , , 377 

Carotid  arteries, ib. 

External  carotid, , 378 

Superior  thyroid,  lingual,  and  labial, ib. 

Muscular,  occipital,  posterior,  auricular,  and  pharyngeal, 380 

Transverse  facial,  temporal,  and  internal  maxillary,  381 

Internal  carotid, , 382 

Ophthalmic  and  cerebral  arteries, ib. 

Subclavian  arteries, , 384 

Vertebral,  basilar,  thyroid  axis,  internal  mammary,  &c 385 

Axillary  artery, 387 

Brachial  artery, 388 

Profunda  arteries,  &c 389 

Ulnar  artery, , 390 

Radial  artery, 391 

Thoracic  aorta 392 

Bronchial,  oesophageal,  and  intercostal  arteries, 393 

Abdominal  aorta, ib. 

Phrenic  arteries, ib. 

Cffiliac  axis, .... 394 

Mesenteric  and  renal  arteries, 395 

Spermatic,  lumbar  and  middle  sacral  arteries, 396 

Internal  iliac  arteries, , 397 

Glutaeal,  obturator,  pudic,  &c 398 

External  iliac,  400 

Femoral  artery, ib. 

Profunda  artery, 401 

Circumflex  arteries, ib. 

Popliteal  artery, 402 

Anterior  tibial  artery, 403 

Posterior  tibial, ib. 

Peronseal  arteries 404 

VENOUS  SYSTEM, 405 

Veins  of  the  head, ib. 

External  jugular  vein, 406 

Internal  jugular  vein, ib. 

Veins  of  the  arm,  ib. 

VensB  innominatse, 407 

Vena  cava  superior, ib. 

Vena  azygos,  ib. 

Veins  of  the  leg, 408 

Iliac  veins, ib. 

2 


XIV  CONTENTS. 

PAGE. 

Vena  cava  inferior 409 

Vena  port®, ib. 

Haemorrhoidal,  mesenteric,  and  splenic  veins, ib. 

LYMPHATIC  SYSTEM, 410 

Thoracic  duct, 411 

Receptaculura  chyli, ib. 

Structure  of  coats  in  arteries,  veins,  and  lymphatics, 412 

Foetal  circulation, 413 

Umbilical  vein, ib. 

Ductus  venosus, ib. 

Ductus  arteriosus, ib. 

Thymus  gland, 414 


PART  IV. 


OF  THE  BONES. 

The  vertebrae,... 415 

Sternum, 423 

Ribs, 425 

Thorax, , 427 

Sacrum, 428 

Ossa  coccygis, 429 

Ossa  innominata, 430 

Ilium, ib. 

Ischium, 431 

Pubis,  432 

Acetabulum, ib. 

Pelvis, 433 

Head,  436 

Frontal  bone, ib. 

Parietal, 439 

Occipital,  440 

Temporal, 441 

./Ethmoid, 444 

Sphenoid,  ; 446 

Sutures, 449 

Skull  in  general, 451 

Bones  of  the  face, 452 

Malar  bone,  453 

Superior  maxillary  bone, ib. 

Palate  bone, 455 

Inferior  spongy  or  turbinated  bone, 456 

Os  unguis  or  lachrymal  bone, 457 

Nasal  bone, ib. 

Vomer, 458 

Inferior  maxillary  bone,  ib. 

Teeth, 460 


CONTENTS.  XV 

PAGE. 

Orbit, 461 

Palatine  region, 462 

Temporal  fossa, ib. 

Zygomatic  fossa, ib. 

Pterygo-maxillary  fo ssa, 463 

Femur,  ib. 

Patella  or  rotula,  466 

Tibia, ib. 

Fibula, 468 

Tarsal  bones, 471 

Metatarsal, 472 

Phalanges, 473 

Clavicle, 474 

Scapula, 475 

Humerus, 477 

Ulna, 479 

Radius, 480 

Carpal  bones, , 482 

Metacarpal  bones, 484 

Phalanges, 485 

Sesamoid  bones, 486 


PART  V. 


OF  THE  JOINTS. 

General  view  of  the  joints, 489 

Temporo-maxillary  articulations, 491 

Dislocations  of  the  lower  jaw, 493 

Articulation  of  the  occiput  with  the  atlas,  ib. 

Articulation  of  the  occiput  with  the  axis, 494 

Articulation  between  the  first  and  second  vertebrae, 495 

Common  articulation  of  the  vertebrae, 496 

Inter. vertebral  ligaments  or  fibro-cartilages, 497 

Articulation  between  the  pelvis  and  the  spine, 499 

Ligaments  of  the  pelvis, 500 

Articulations  of  the  ribs, 501 

LIGAMENTS  OF  THE  SUPERIOR  EXTREMITIES, 503 

Sterno-clavicular  articulation, 504 

Scapulo-clavicular  articulation , 505 

Dislocations  of  the  clavicle, ib. 

Ligaments  of  the  scapula, 506 

Humero-scapular  or  shoulder  articulation, ib. 

Dislocations  of  the  shoulder, 508 

Humero-cubital  articulation,  or  the  elbow  joint, 509 

Radio-ulnar  articulations, 510 

Dislocations  of  the  bones  of  the  elbow  joint, ib. 

Dislocations  of  the  carpal  extremities  of  the  radius  or  ulna,....  511 


Xvi  CONTENTS. 

PAGE. 

Radio-carpal  articulation,  or  the  wrist  joint, 512 

Articulations  of  the  bones  of  the  carpus, 513 

Dislocations  of  the  bones  of  the  carpus, 515 

Articulation  between  the  carpus  and  metacarpus, ib. 

Dislocations  of  the  metacarpal  bones  from  the  carpus, ib. 

Articulation  between  the  metacarpus  and  the  phalanges, 516 

Dislocation  of  the  thumb, ib. 

LIGAMENTS  OF  THE  INFERIOR  EXTREMITIES, 517 

Ilio-femoral  articulation,  or  the  hip  joint, ib. 

Dislocations  of  the  hip, , 519 

Femoro-tibial  articulation,  or  the  knee  joint, , 52 1 

Dislocations  of  the  patella  and  knee, 526 

Superior  tibio-fibular  articulation,  * 527 

Dislocation  of  the  tibio-fibular  articulation, 528 

Inferior  tibio-fibular  articulation, ib. 

Articulation  of  the  ankle, ib. 

Dislocations,  &c.  of  the  ankle, 530 

Articulations  of  the  bones  of  the  tarsus, 531 

Articulations  between  the  tarsus  and  meta-tarsus,  &c ib. 


APPENDIX. 

Direction  for  making  dried  preparations  of  arteries, 535 

Laennec's  division  of  the  regions  of  the  thorax, 539 

Directions  for  opening  the  head,  thorax,  and  abdomen, 540 


THE 


DUBLIN   DISSECTOR 


CHAPTER   I. 

DISSECTION  OF  THE  EXTERNAL  PARTS  OF  THE 
FACE  AND  HEAD, 


- 


SECTION  I. 


EXTERNAL    PARTS    OF    THE    HEAD. 

THE  integuments  covering  the  cranium  are  firm  and  dense, 
although  when  felt  they  give  the  sensation  of  being  thin  : 
the  cuticle  is  delicate,  but  the  cutis  is  very  thick,  and  fur- 
nished with  many  sebaceous  follicles ;  the  subjacent  cel- 
lular membrane  contains  granulated  fat,  and  the  bulbs  of 
the  hairs,  which  afterwards  perforate  the  skin  in  an  oblique 
direction.  The  cellular  tissue  is  condensed,  having  some- 
what a  ligamentous  structure,  it  adheres  so  intimately  to 
the  subjacent  muscular  and  tendinous  expansion,  that  the 
inexperienced  student  may  find  some  difficulty  in  exposing 
the  surface  of  the  latter.  Make  an  incision  through  the 
integuments  along  the  median  line,  from  the  tuberosity  of 
the  occipital  bone,  as  far  forwards  as  the  lower  part  of  the 
forehead,  from  each  extremity  of  this,  make  a  transverse 
incision  about  three  inches  long  ;  let  the  posterior  one  be 
parallel  to  the  superior  transverse  ridge  of  the  occipital 
bone,  and  the  anterior  one  parallel,  and  about  half  an  inch 
superior  to  the  eyebrow ;  cautiously  dissect  off  the  integu- 
ments from  the  subjacent  muscular  and  tendinous  expan- 
sion, which  is  the  occipito-frontalis.  This  muscle,  like 
most  of  the  superficial  muscles  of  the  face,  is  closely  at- 
tached to  the  skin,  which  circumstance,  added  to  the  pale- 
ness and  smallness  of  their  fibres,  renders  their  dissection 
somewhat  difficult  and  tedious.  Most  of  the  superficial 


2  DUBLIN    DISSECTOR. 

muscles  of  the  head  and  face,  during  life,  assist  some  of 
the  organs  of  sense,  and  contribute  to  produce  certain 
changes  in  the  countenance,  indicative  of  character  or 
passion,  and  expressive  of  many  diseases,  tetanus,  perito- 
nitis, &c.  In  point  of  function,  they  may  be  considered 
as  belonging  to  the  class  of  mixed  muscles,  that  is,  they 
are  in  part  voluntary  and  in  part  involuntary :  with  the 
exception  of  the  aponeurosis  of  the  occipito-frontalis,  the 
tendon  of  the  orbicularis  palpebrarum,  and  that  of  the 
corrugator  supercilii,  there  is  no  perfect  tendinous  struc- 
ture in  the  other  muscles  of  this  class. 

The  superficial  muscles  of  the  head  are  divided  into 
those  of  the  cranium  and  face.  Those  of  the  cranium  are 
the  occipito-frontalis,  and  the  three  common  muscles  of 
the  ear,  to  these  some  add  the  corrugatores  superciliorum ; 
these,  however,  I  prefer  placing  among  the  muscles  of  the 
face. 

[The  following  arrangement  will  give  a  comprehensive  view  of  the 
muscles  of  the  head  and  face,  classed  according  to  the  part  upon 
which  they  particularly  act.  There  are  six  classes,  including  thirty, 
six  pair  of  muscles,  and  two  single  muscles  as  follows  : 

FIRST  CLASS,  ONE  MUSCLE. 

Occipito  Frontalis. — Vide  p.  4. 

This  by  its  palpebral  insertion  becomes  a  muscle  of  the  eye,  and 
by  its  nasal  process,  a  muscle  of  the  nose ;  it  acts  upon  the  scalp, 
eyebrow,  lid,  and  nose. 

SECOND  CLASS,  ELEVEN  MUSCLES. 

These  are  the  muscles  of  the  ear,  and  are  arranged  in  three  groups, 
the  first  of  three  muscles  moves  the  external  ear,  upon  the  head ;  the 
second  of  five  muscles,  moves  the  cartilages  of  the  external  ear,  up. 
on  themselves :  the  third  of  three  muscles  moves  the  bones  of  the 
internal  ear  so  as  to  render  the  membrana  tympani,  lax  or  tense. 

First  Group,  three  Muscles. 
Superior  Auris,  or  Attollens.— Vide  p.  6. 
Anterior  Auris,  or  Attrahens,  )  -y  • ,        _ 
Posterior  Auris,  orRetrahens,  \  v'aeP-  '• 

Second  Group,  five  Muscles. 
Tragicus,  ") 

Anti  Tragicus, 

Helicis  Major,  V  Vide  p.  355. 

Helicis  Minor, 
Transversalis  Auris,  J 

Third  Group,  three  Muscles. 
S  taped  ius,  } 

Tensor  Tympani,    >  Vide  p.  355. 
Laxator  Tympani,  ) 


DUBLIN    DISSECTOR.  3 

THIRD  CLASS,  ELEVEN   MUSCLES, 

Including  the  occipito-frontalis.  These  are  the  muscles  of  the  eye, 
and  are  found  in  two  groups,  the  one  of  five  muscles,  acting  upon 
the  appendages  of  the  eye,  the  other  of  six  muscles,  acting  upon  the 
ball  of  the  eye. 

First  Group,  fine  Muscles. 

Occipito-frontalis.,  its  palpebral  insertion,  Vide  p.  14. 

Corrugator  Supejrcilii.  "     "  16. 

Levator  Palpebra;  Superioris,  "     "  361. 

Orbicularis  Palpebrarum,  "     "  8. 

Tensor  Tarsi,  "     "  10. 

These  muscles  are  .all  exterior  to  the  orbit  except  the  Levator  Pal- 
pebroe  Superioris  which  is  within. 

Second  Group,  six  Muscles,  all  within  the  orbit. 
Superior  Rectus,  or  Levator  oculi, 
Inferior  Bectus,  or  Depressor  oculi, 
Internal  Rectus,  or  Adductor  oculi, 
External  Rectus,  or  Abductor  oculi, 
Obliquus  Superior, 
Obliquus  Inferior, 

FOURTH  CLASS,  FOUR  MUSCLES. 

These  are  the  muscles  which  act  upon  the  nose,  and  they  .are  ar- 
ranged in  two  groups,  the  one  of  two  muscles  proper  to  the  nose ; 
the  other  also  of  two  muscles  common  to  the  nose  .and  upper  lip. 

First  Group,  two  Muscles,  proper  to  the  nose. 
Pyramidalis  Nasi,  a  process  of  the  occipito-frontalis, 
Compressor  Nasi, 

Second  Group,  two  Muscles,  common  to  the  nose  and  upper  Lip. 
Levator  Labii  Superioris  alaeque  nasi,  Vide  p.  11. 

Depressor  Labii  Superioris  alaeque  nasi,  "     "  J2. 

FIFTH  CLASS,  TEN  MUSCLES.. 

These  are  the  muscles  which  act  upon  the  different  parts  of  the 
mouth  and  are  arranged  in  four  groups,  the  first  group  includes  but 
one  muscle,  which  surrounds  the  whole  mouth  ;  the  second  embraces 
two  muscles,  which  act  upon  the  upper  lip  (already  enumerated,  as 
common  to  it,  and  the  nose)  the  third  includes  two  muscles,  which 
act  upon  the  lower  lip,  and  the  fourth  five  muscles,  which  act  upon 
the  angle  of  the  mouth. 

First  Group,  one  muscle — a  single  muscle. 

Orbicularis  Oris — Vide  p.  13. 

Second  Group,  two  Muscles,  common  to  the  upper  lip  and  nose. 
Levator  Labii  Superioris  alasque  nasi,  Vide  p.  11. 

Depressor  Labii  Superioris  aleeque  nasi,  "     "  12. 

Third  Group,  two  muscles. 

Levator  Labii  Inferioris,  Vide  p.  13. 

Depressor  Labii  Inferioris,  "     "  12. 


4  DUBLIN    DISSECTOR. 

Fourth  Group,  five  Muscles. 

Levator  Anguli  Oris,  Vide  p.  12. 

Depressor  Anguli  Oris,  "     "    12. 

Zygomaticus  Major,  «*      "11. 

Zygomaticus  Minor,  "      "  11. 

Buccinator,  "      "  13. 

In  the  case  of  the  eyelids,  the  contraction  of  the  orbiculans  and 
consequent  disfiguration  is  guarded  against,  by  the  cartilaginous 
tarsi  placed  along  the  adjoining  margins  of  the  lids  ;  but  in  the 
case  of  the  mouth,  the  contraction  of  the  orbicularis  and  consequent 
disfiguration,  is  guarded  against  by  the  numerous  muscles  just  men- 
tioned, and  which  are  inserted  extensively  into  the  lips  and  their 
commissures  or  angles ;  this  is  demonstrated  by  the  distortion  of  the 
mouth,  in  those  cases  where  one  side  of  the  face  is  paralysed. 

SIXTH   CLASS,    FOUR   MUSCLES. 

These  muscles  act  upon  the  inferior  maxillary  bone,  in  raising  the 
jaw  and  in  mastication ;  they  are  variously  situated,  one  being  on 
the  side  of  the  face,  one  on  the  side  of  the  head,  and  the  other  two 
beneath  the  base  of  the  cranium,  and  within  the  inferior  maxilla. 
They  constitute  one  group. 

Masseter,  Vide  p.  19. 

Tempor&lis,  "     "    21. 

Pterygoideus  Intern  us,  "     "  22. 

Pterygoideus  Externus,  "     "   23. 

Of  all  the  muscles  above  enumerated,  the  orbicularis  oris  and  the 
occipito-frontalis,  are  the  only  two,  usually  described  as  single 
muscles,  all  the  rest  being  in  pairs.  The  last  mentioned  group  of 
muscles  are  those  which  are  concerned  in  dislocations  of  the  lower 
jaw.] 

OCCIHTG-FKONTAMS  as  the  only  muscle  which  properly 
belongs  to  the  scalp  ;  it  is  a  thin,  broad,  digastric,  or 
rather  quadriceps  muscle,  fleshy  at  each  extremity,  apo- 
neurotic  in  the  centre.  It  arises  on  each  side  by  tendinous 
and  fleshy  fibres,  from  the  two  external  thirds  of  the  su- 
perior transverse  ridge  of  the  occipital  bone,  and  from  the 
external  and  posterior  part  of  the  mastoid  process ;  the 
fibres  on  each  side  ascend  from  behind  forwards  and 
from  without  inwards,  and  soon  terminate  in  one  thin  and 
broad  tendon,  which  extends  over  the  upper  and  lateral 
parts  of  the  cranium. — This  epicranial  aponeurosis  having 
arrived  opposite  the  coronal  suture,  ends  in  two  fleshy 
portions,  broader  and  thicker  than  the  posterior  extremi- 
ties of  the  muscle;  these  anterior  portions,  which  are 
thicker  externally  than  internally,  descend  over  the  front- 
al bone,  and  are  inserted,  fleshy  on  each  side,  into  the  inte- 
gument of  the  eyebrow,  mixing  with  the  fibres  of  the  cor- 
rugator  supercilii  and  orbicularis  palpebrarum  muscles : 


DISSECTOR.  5 

a  small  fleshy  slip  is  often  continued  down  along  the  nasal 
bones,  and  is  attached  to  the  angular  process  of  the  os 
frontis,  and  inferiorly  to  the  nasal  bones  or  cartilages :  this 
slip  is  described  by  some  as  a  distinct  muscle,  under  the 
name  of  pyramidalis  nasi,  or  fronto-nasalis.  Use.  The  occipi- 
to-frontalis  muscle  can  raise  the  eyebrows  and  integument 
of  the  forehead  in  transverse  wrinkles,  draw  the  eyebrows 
a  little  outwards,  and  make  tense  the  skin  of  the  upper 
eyelids,  and  thus  expose  the  eyeball,  as  in  staring,  it  can 
also  pull  the  scalp  backwards ;  but  if  the  eyebrows  be  de- 
pressed and  fixed,  this  muscle  can  then  (particularly  in 
some  persons)  draw  the  scalp  downwards  and  forwards. 
This  muscle  is  very  closely  connected  to  the  scalp,  par- 
ticularly in  front,  but  loosely  to  the  cranium,  it  can  thus 
move  easily  on  the  latter,  carrying  with  it  the  former, 
which  it  also  serves  to  support  in  apposition  with  the  cra- 
nium, so  as  to  prevent  the  skin  slipping  or  yielding  when 
any  weight  is  pressed  against  the  head. 

Its  origin  is  connected  with  the  sterno-mastoid,  the  tra- 
pezius,  and  splenius  muscles,  and  its  insertion  with  those 
of  the  eyebrows.  Some  describe  the  occipito-frontalis, 
not  as  one,  but  as  four  distinct  muscles,  two  on  each  side, 
under  the  names  of  the  occipital  and  frontal  muscles  of 
each  side,  and  consider  the  cranial  aponeurosis  as  their 
common  insertion.  Several  vessels  and  nerves  perforate 
this  muscle,  and  ramify  on  its  surface  and  in  the  integu- 
ment, viz.  anteriorly  the  supra-orbital  branches  of  the 
ophthalmic  nerve  and  artery  ;  laterally,  the  temporal  and 
posterior  auris  arteries  with  branches  of  the  portio  dura 
and  inferior  maxillary  nerves,  and  posteriorly,  the  occipi- 
tal arteries  spread  their  branches  upwards  and  forwards, 
accompanied  by  the  occipital  nerves,  branches  of  the  cer- 
vical plexus.  It  covers  from  behind  forwards,  the  occipi- 
tal, temporal,  parietal,  and  frontal  bones,  also  the  upper 
portion  of  each  temporal  aponeurosis,  the  corrugator  su- 
percilii  muscle,  and  the  supra-orbital  nerves  and  vessels. 
The  cranial  or  epicranial  aponeurosis  is  composed  of  ten- 
dinous fibres  which  are  distinct,  glistening,  and  parallel 
behind,  but  anteriorly  become  weak,  greyish,  and  inter- 
laced like  cellular  tissue,  and  frequently  deficient  in  spots. 

The  integuments  in  this  region  are  highly  organized, 
being  supplied  with  numerous  nerves  and  vessels,  these 
are  derived  from  different  and  distant  sources,  and  are 
chiefly  destined  to  nourish  the  hair  bulbs  in  the  cellular 
tissue ;  in  the  line  of  the  sutures  they  have  frequent  in- 
osculations with  the  vessels  of  the  diploe,  and  of  the  dura 
mater.  This  high  organization  of  the  scalp  is  not  only  of 
anatomical  but  of  practical  importance,  as  it  serves  to  ex- 


6  DUBLIN    DISSECTOR. 

plain  many  of  the  pathological  phsenomena  which  are  of 
ordinary  occurrence  in  this  region ;  thus,  it  is  frequently 
the  seat  of  encysted  tumours,  horny  growths,  &c.,  these 
appear  to  arise  in  the  sebaceous  follicles,  the  ducts  of 
which  have  become  obstructed  from  irritation  or  injury  ;  a 
vitiated  secretion  then  accumulates  in  the  sac,  which  some- 
times becomes  circularly  enlarged,  and  at  others  the  con- 
tents slowly  escaping  from  the  ducts,  and  hardening,  as- 
sume horny  and  various  other  appearances.  The  scalp  is 
a  common  seat  of  erysipelas,  both  idiopathic  and  sympto- 
matic. Injuries  of  it  are  of  very  frequent  occurrence,  and 
are  more  serious  than  those  of  the  same  extent  in  other 
situations.  Incised  wounds  bleed  more  freely  ;  punctured 
wounds  are  very  frequently  followed  by  high  inflamma- 
tory symptoms,  local  and  general,  in  consequence  of  mat- 
ter being  confined  under  the  tense  epicranial  aponeurosis, 
which,  in  such  cases,  will  require  free  division.  The 
compact  density  of  the  cellular  tissue  explains  the  hard 
rim  which  surrounds  the  ecchymosis,  the  effect  of  injury, 
[and  also  explains  the  deceptive  appearance  of  fracture  and  depres- 
sion of  the  bone  which  is  sometimes  presented  when  the  injury  is  in 
fact  merely  a  contusion  followed  by  the  effusion  of  blood.  As  above 
stated  the  scalp  is  very  abundantly  supplied  with  blood  which  is  de- 
rived principally  from  the  frontal  branches  of  the  internal  carotid,  and 
the  temporal,  posterior  auricular,  and  occipital  branches  of  the  ex- 
ternal carotid ;  these  anastomose  very  freely  with  each  other,  on 
the  same  side,  and  also  very  freely  across  the  top  of  the  head  with 
the  same  branches  of  the  opposite  side,  and  hence  the  severe  and 
extensive  operation  which  is  necessary  for  aneurism  by  anastomosis 
of  the  scalp,  which  operation  consists  in  circumscribing  the  tumor, 
sometimes  even  after  the  common  carotid  artery  of  the  affected 
side  has  been  ligatured.  Foran  extensive  aneurism  of  this  kind, both 
common  carotid  arteries  were  ligatured  with  perfect  success,  by 
Prof.  Mussey,  at  that  time  of  Dartmouth  College.  The  scalp  is 
also  the  seat  of  encephaloid  disease  and  nsevi  materni.J 

In  the  foetus  the  scalp  is  very  thin,  and  the  aponeurosis 
is  loosely  attached  to  the  cranium  by  reticular  membrane; 
this,  and  not  the  subcutaneous  cellular  tissue  is  the  seat  of 
those  large  ecchymoses  eo  commonly  seen  after  parturi- 
tion, and  which  in  general  are  quickly  removed  by  the 
absorbent  system. 

The  common  muscles  of  the  ear  are  three  in  number, 
viz.  superior,  anterior,  and  posterior  auris  : 

SUPERIOR  AURIS,  or  ATTOLLENS  AUREM,  is  a  small,  thin, 
triangular  muscle,  situated  on  the  temple,  and  above  the 
ear,  arising  broad  and  tendinous  from  the  cranial  aponeu- 
rosis, where  it  covers  the  temporal  fascia  on  the  side  of 
the  cranium,  just  above  the  external  ear ;  the  fibres  de- 
scend converging,  become  fleshy,  and  are  inserted  into  the 


DUBLIN    DISSECTOR.  7 

upper  and  interior  part  of  the  cartilage  of  the  ear : — use, 
to  raise  the  cartilage,  and  deepen  the  meatus  of  the  ear,  also 
to  make  tense  the  epicranial  fascia.  This  muscle  is  be- 
tween the  skin  and  temporal  fascia,  its  anterior  edge  is 
confounded  with  the  following  muscle. 

ANTERIOR  AURIS,  or  ATTRAHENS  AUREM,  is  connected 
with  the  last,  is  of  the  same  form,  but  smaller,  and  often 
indistinct ;  it  arises  from  the  posterior  part  of  the  zygoma- 
tic  process,  and  from  the  cranial  aponeurosis,  passes  back- 
wards and  downwards,  and  is  inserted  into  the  anterior 
part  of  the  helix ;  use,  to  draw  the  external  ear  forwards 
and  upwards.  This  muscle  is  superficial,  and  lies  on  the 
temporal  fascia,  vessels,  and  nerves,  its  lower  edge  is  lost 
in  the  cellular  tissue. 

POSTERIOR  AURIS,  or  RETRAHENS  AUREM,  often  consists  of 
two  or  three  distinct  fasiculi,  it  is  the  strongest  of  these 
auricular  muscles ;  it  has  no  connection  to  the  epicranial 
fascia,  but  arises  from  the  mastoid  process  above  the  ster- 
no-mastoid  muscle,  passes  forwards,  and  is  inserted  into 
the  back  part  of  the  concha ;  use,  to  enlarge  the  meatus  of 
the  ear  and  direct  it  backwards.  This  muscle  is  covered 
only  by  the  skin,  it  lies  upon  the  temporal  bone. 

In  addition  to  these  muscles,  which  move  the  external 
ear,  there  are  several  small  muscles  attached  to  different 
parts  of  the  cartilages,  which  serve  to  alter  their  form, 
and  expand  their  cavities ;  these  muscles,  as  also  those  in 
the  tympanum,  shall  be  described  hereafter  in  the  dissec- 
tion of  the  organ  of  hearing.* 


SECTION  II. 


DISSECTION    OF    THE    EXTERNAL     PARTS     OF    THE    FACE. 

The  muscles  of  the  face  require  careful  dissection ;  they 
are  delicate,  and  often  very  pale ;  they  may  be  classed 
into  the  superficial  and  deep :  the  former  into  those  of 
the  eyelids,  nose,  lips,  and  mouth ;  the  latter  into  those  of 
the  lower  jaw  and  palate.  Make  an  incision  around  the 
base  of  the  orbit,  through  the  skin,  which  is  here  very 

*Previous  to,  or  immediately  after  dissecting  the  muscles  of  the  face,  the  student 
should  examine  the  brain,  the  description  of  which  organ  will  be  found  at  the 
head  of  that  of  the  nervous  system. 


8  DUBLIN    DISSECTOR. 

fine,  and  closely  adhering  to  the  fibres  of  the  orbicularis 
muscle;  next  make  a  perpendicular  incision  along  the 
middle  line  of  the  nose,  to  the  centre  of  the  upper  lip, 
continue  this  in  a  semicircular  manner  round  the  angle  of 
the  mouth  to  the  middle  of  the  lower  lip,  and  thence  to 
the  chin,  and  lastly  from  the  chin  to  the  angle  of  the  jaw  ; 
reflect  the  integuments  cautiously  from  the  eyelids  and 
side  of  the  face,  as  far  back  as  the  ear,  avoiding  the  slender 
muscular  fibres  which  adhere  to  the  skin,  and  the  vessels 
and  nerves  which  will  be  exposed  in  this  dissection. 

The  superficial  muscles  of  the  face  may  be  considered 
as  thirty-three  in  number,  that  is  sixteen  pair  and  one 
azygos,  and  are  arranged  as  follows. 

Three  pair  belong  to  the  palpebrcc.,  viz.  orbicularis  pal- 
pebrarum,  tensor  tarsi,  and  corrugator  supercilii,  (the  le- 
vator palpebrse  is  deep  seated  in  the  orbit,  and  is  arranged 
among  the  muscles  of  that  region.) 

Four  pair  belong  to  the  nose,  viz.  pyramidalis  nasi,  leva- 
tor  labii  superioris  alseque  nasi,  compressor  and  depres- 
sor naris. 

Three  pair  belong  to  the  upper  lip,  viz.  levator  labii 
superioris,  levator  anguli  oris,  and  depressor  labii  superi- 
oris. 

Three  pair  belong  to  the  lower  lip,  viz.  depressor  anguli 
oris,  depressor  labii  inferioris,  and  levator  labii  inferioris. 

Three  pair  belong  to  the  mouth,  viz.  zygomaticus  major, 
minor,  and  buccinator,  and  one  azygos,  the  orbicularis 
oris  ;  writers  vary  this  arrangement,  but  no  material  dif- 
ference exists. 

ORBICULARIS  PALPEBRARUM,  broad  and  thin,  somewhat 
oval,  in  some  subjects  very  pale  and  indistinct,  in  others 
strong  and  well  marked,  it  surrounds  the  base  of  the  orbit, 
and  occupies  a  great  portion  of  the  face ;  it  arises  by  sev- 
eral fleshy  fibres  from  the  internal  angular  process  of  the 
os  frontis,  and  from  the  upper  edge  of  a  small  horizontal 
tendon,  (which  tendon,  TENDO  OCULI,  or  TENDO  PALPEBRARUM, 
[or  internal  Palpebral  Ligament,]  which  is  nearly  one  half 
of  an  inch  in  length,  is  inserted  internally  into  the  upper 
end  of  the  nasal  process  of  the  superior  maxillary  bone, 
thence  it  passes  outwards  and  backwards  to  the  internal 
commissure  of  the  eyelids,  where  it  forks  into  two  slips 
which  enclose  the  caruncula  lachrymalis,  and  are  then 
inserted  each,  into  the  tarsal  cartilage,  and  the  lachrymal 
duct ;)  the  fleshy  fibres  then  proceed  in  curves,  upwards 
and  outwards,  along  the  upper  edge  of  the  orbit,  the  eye- 
lid, and  tarsal  cartilage,  as  far  as  the  temple  and  external 
commissure  of  the  eyelids ;  thence  the  fibres  curve  in  a 
similar  manner  along  the  inferior  eyelid  and  edge  of  the 


DUBLIX    DISSECTOR.  9 

orbit  to  the  internal  canthus,  where  the  fibres  are  inserted 
into  the  nasal  process  of  the  superior  maxilla,  and  into  the 
inferior  edge  of  the  horizontal  tendon. — Use,  to  close  the 
eyelids,  chiefly  by  depressing  the  superior,  the  levator 
muscle  of  which  it  directly  opposes,  it  also  serves  to  press 
the  tears  inwards  towards  the  puncta  lachrymalia ;  the 
superior  and  external  fibres  can  depress  the  eyebrow,  and 
thus  oppose  the  occipito-frontalis  and  shade  the  eye  ;  the 
inferior  fibres  can  raise  the  cheek,  raise  and  draw  the  low- 
er eyelid  inwards,  and  compress  the  lachrymal  sac,  which 
they  cover.  In  sleep  it  is  relaxed,  and  the  eye  is  covered 
chiefly  by  the  descent  of  the  upper  palpebra,  its  elevator 
being  also  relaxed:  when  awake  its  contraction  covers  the 
globe,  not  only  by  bringing  down  the  upper,  but  also  by 
elevating  the  lower  eyelid,  hence  the  "equator  oculi,"  the 
line  formed  by  the  approximated  tarsi,  is  lower  during  real 
than  in  feigned  sleep ;  in  the  former,  also,  the  cornea  is 
seldom  entirely  covered,  as  it  always  is  in  the  latter. 

This  muscle  is  covered  by  aad  adheres  to  the  skin  :  su- 
periorly it  intermixes  with  the  oocipito-frontalis,  and  covers 
the  corrugator  supeircilii,  the  frontal  vessels  and  nerves, 
the  tarsal  cartilage  <mnd  ligament,  and  the  levator  palpebrse 
superioris  ;  infer iorly  it  intermixes  with  the  muscles  of  the 
cheek  and  lips,  and  sometimes  with  the  platysma  myoides, 
and  covers  the  malar  bone,  the  inferior  tarsus  and  its  liga- 
ment, the  origin  of  the  levator  anguli  oris,  levator  labii 
superioris,  and  the  infra  orbital  vessels  and  nerves.  The 
external  or  orbital  fibres  of  this  muscle  are  strong  and  red, 
and  run  circularly  round  the  base  of  the  orbit ;  the  mid- 
dle or  palpebral  fibres  are  pale,  thin,  and  scattered,  and  are 
contained  in  the  eyelids-;  the  internal  or  -ciliary  portion  is 
a  thick  but  pale  fasciculus,  situated  under  the  cilise,  at  the 
edge  of  each  eyelid.  The  palpebral  and  ciliary  portions 
adhere  more  closely  to  the  skin,  and  present  an  elliptical 
appearance,  as  the  fibres  from  the  upper  and  lower  eyelid 
intersect  each  other  at  the  outer  canthus,  and  adhere  to  the 
ligament  of  the  external  commissure.  The  horizontal 
tendon  of  this  muscle  passes  across  the  lachrymal  sac  a 
little  above  its  'Centre,  and  a  strong  aponeurosis  derived 
from  its  upper  and  lower  edge,  covers  all  the  anterior  sur- 
face of  the  sac,  and  adheres  to  the  margins  of  the  bony 
gutter,  in  which  it  is  lodged,  where  it  becomes  continuous 
with  the  periosteum.  This  tendon  can  be  seen  or  felt 
through  the  integuments  during  life,  particularly  when  the 
muscle  is  in  action,  or  when  the  eyelids  are  drawn  towards 
the  temple. 

This  muscle  is  of  the  mixed  class  :  it  sympathizes  with 
the  eye  in  a  remarkable  and  most  useful  manner  ;  it  pos- 


10  DUBLIN    DISSECTOR. 

sesses  great  irritability,  particularly  in  children  ;  in  puru- 
lent and  strumous  ophthalmia  it  is  frequently  spasmodi- 
cally contracted,  and  totally  prevents  the  eye  being  seen  : 
this  affection  is  somewhat  analogous  to  the  spasmodic  con- 
striction of  the  sphincter  ani  muscle. 

In  the  operation  of  opening  the  lachrymal  sac,  the  in- 
cision should  commence  immediately  below  this  tendon  so 
as  to  avoid  injuring  it,  and  be  carried  obliquely  downwards 
and  outwards,  to  the  extent  of  about  half  an  inch. 

Separate  the  orbicularia  from  the  occipito-frontalis  over 
the  internal  half  of  the  superciliary  arch,  the  tensor  tarsi 
and  the  corrugator  supercilii  muscles  will  be  exposed. 

TENSOR  TARSI,  arises  tendinous  from  the  posterior  edge 
of  the  os  iinguis,  where  it  joins  the  os  planum,  passes  for- 
wards between  the  conjunctiva  and  the  expansion  of  the 
tendo  oculi  which  covers  the  lachrymal  sac,  divides  into 
two  portions,  which  are  inserted  into  the  lachrymal  ducts, 
along  which  the  fibres  extend,  nearly  as  far  as  the  puncta : 
use,  to  draw  the  puncta  and  eyelids  into  close  contact  with 
the  eye,  also  to  press  the  puncta  towards  the  nose,  to  com- 
press the  lachrymal  sac,  and  to  force  out  the  secretion  from 
the  follicles  of  the  caruncula  lachrymalis.  This  muscle  is 
also  named  HORNER'S  muscle  from  its  discoverer,  it  will  be 
better  seen  if  the  two  tarsi  be  divided  about  their  middle, 
and  their  inner  portions  turned  towards  the  nose. 

CORRUGATOR  SUPERCILII,  arises  fleshy  and  tendinous  from 
the  internal  angular  process  of  the  os  frontis,  passes  up- 
wards and  outwards,  and  is  inserted  into  the  middle  of  the 
eyebrow,  mixing  with  the  orbicularis  and  occipito-frontalis 
muscles :  use,  to  depress  and  approximate  the  eyebrows, 
throwing  the  skin  of  the  forehead  into  vertical  wrinkles : 
this  pair  of  muscles  is  voluntary  but  they  cannot  act  sepa- 
rately ;  they  directly  oppose  the  occipito-frontalis  and 
shade  the  eye.  They  are  covered  by  the  orbicularis  and 
occipito-frontalis,  and  lie  on  the  os  frontis,  and  on  the 
frontal  nerve  and  vessels. 

PYRAMIDALIS  NASI,  superficial,  long,  thin,  often  wanting, 
arises  from  the  occipito-frontalis,  descends  close  to  its  fel- 
low, covering  the  nasal  bones  and  sutures,  becomes  broad 
and  aponeurotic,  and  is  inserted  into  the  compressor  nasi 
muscle.  Use,  it  raises  the  skin  covering  the  ossa  nasi. 

COMPRESSOR  NASI,  is  thin  and  triangular,  placed  on  the 
side  of  the  nose,  between  the  skin  and  the  cartilage ;  it 
arises  from  the  inner  side  of  the  canine  fossa,  in  the  supe- 
rior maxilla ;  the  fibres  pass  forwards,  expanding  over  the 
ala  nasi,  and  are  inserted  by  a  thin  aponeurosis  into  the  dor- 
sum  of  the  nose,  joining  some  fibres  from  the  opposite  side : 
use,  to  press  the  ala  toward  the  septum,  or  to  draw  it  from  it, 


DUBLIN    DISSECTOR.  11 

so  that  it  may  alternately  enlarge  or  dimmish  the  anterior 
nares.  The  insertion  of  this  muscle  is  connected  with  the 
occipito-frontalis,  and  its  origin  with  the  following  muscle 
which  partly  covers  it. 

LEVATOR  LABII  SUPERIORIS  ALJEQUE  NASI,  is  long,  thin, 
and  triangular,  placed  on  the  side  of  the  nose,  between  the 
orbit  and  the  upper  lip ;  it  arises  by  two  origins ;  first, 
from  the  upper  extremity  of  the  nasal  process  of  the  supe- 
rior maxilla :  second,  broad,  from  the  edge  of  the  orbit, 
above  the  infra-orbital  hole ;  the  fibres  descend  and  con- 
verge a  little,  and  are  inserted  into  the  ala  nasi,  and  into  the 
upper  lip  and  orbicularis  oris  muscle :  its  name  denotes 
its  use.  The  superior  and  orbital  origins  of  this  muscle  are 
covered  by  the  orbicularis  palpebrarum,  the  inferior  por- 
tion is  superficial ;  the  angular  vein  and  artery  separate  its 
origins :  the  orbital  head  covers  the  infra-orbital  nerve  and 
vessels  and  the  levator  anguli  and  some  of  the  orbicularis 
oris  muscles.* 

ZYGOMATICUS  MINOR  is  very  small,  and  sometimes  want- 
ing ;  it  arises  from  the  upper  part  of  the  malar  bone,  passes 
downwards  and  forwards,  and  is  inserted  into  the  upper  lip 
near  the  commissure,  uniting  with  the  other  muscles  which 
are  inserted  there  ;  use,  to  draw  the  angle  of  the  mouth  up- 
wards and  outwards,  as  in  smiling ;  it  lies  superior,  and 
parallel  to  the  major,  between  which,  and  the  levator  labii, 
it  is  inserted. 

[This  muscle  is  sometimes  wanting ;  sometimes  double ;  sometimes 
a  slip  from  the  orbicularis  palpebrarum ;  sometimes  it  stops  short  of 
the  angle  of  the  mouth.] 

ZYGOMATICUS  MAJOR,  is  long  and  narrow,  and  inferior  to 
the  last ;  arises  tendinous  and  fleshy  from  the  lower  part  of 
the  malar  bone,  near  the  zygomatic  suture:  it  descends 
obliquely  forwards,  and  is  inserted  into  the  angle  of  the 
mouth. — Use,  to  draw  the  corner  of  the  mouth  upwards  and 
backwards.  The  zygomatic  muscles  are  partly  concealed 
at  their  origin  by  the  orbicularis  palpebrarum ;  their  in- 
sertion intermingles  with  the  levator,  depressor  anguli,  and 
orbicularis  oris  muscles ;  they  lie  on  the  malar  bone,  and 
cross  the  masseter  and  buccinator  muscles,  also  the  labial 
vein  and  artery,  and  they  run  superficial  and  superior  to 

*  The  external  or  orbital  head  of  this  muscle  is  described  by  most  writers  as  a 
distinct  muscle,  and  has  been  enumerated  by  me  as  such ;  it  is  called  Levator 
Labii  Superioris :  as,  however,  it  will  be  found  on  dissection  to  be  inseparably 
connected  with  the  levator  labii  alajque  nasi,  I  prefer  describing  it  as  part  of  the 
outer  head  of  that  muscle  ;  in  like  manner  I  have  united  the  depressor  labii  supe- 
rioris  or  incisor,  and  the  depressor  naris,  which  are  by  some  described  as  distinct 
muscles ;  this  note,  therefore,  may  serve  to  explain  to  the  student  the  different  de- 
scriptions given  of  these  muscles  by  different  authors. 


12  DUBLIN    DISSECTOR. 

the  duct  of  the  parotid  gland ;  they  are  imbedded  in  much 
soft  adipose  substance. 

LEVATOR  ANGULI  ORIS,  (musculus  caninus)  is  situated 
about  the  middle  of  the  face,  behind  and  a  little  external  to 
the  orbital  portion  of  the  levator  labii  superioris  alseque 
nasi,  or  the  levator  labii  of  some ;  arises  from  the  canine 
fossa  in  the  superior  maxillary  bone  immediately  below  the 
infra-orbital  foramen,  and  above  the  alveolus  of  the  first 
molar  tooth  ;  it  descends  obliquely  forwards  and  outwards, 
and  is  inserted  narrow  into  the  commissure  of  the  lips,  and 
into  the  orbicularis  oris ;  its  name  denotes  its  use.  This 
muscle  is  covered  by  the  o-rbicularis  palpebrarum,  levator 
labii  superioris  alseque  nasi,  zygomatic  muscles,  and  by  a 
quantity  of  soft  adeps,  also  by  the  infra-orbital  nerve  and 
vessels,  which  ramify  upon  its  surface,  and  separate  it  from 
the  orbital  portion  of  the  levator  labii  alaeque  nasi :  it  lies 
on  the  superior  maxilla,  the  buccinator  muscle,  and  the 
mucous  membrane  of  the  mouth. 

DEPRESSOR  LABII  SUPERIORIS  ALJEQUE  NASI,  a  small  flat 
muscle,  exposed  by  everting  the  upper  lip,  and  raising  the 
mucous  membrane  on  the  side  of  its  frsenum ;  it  arises  from 
the  alveoli  of  the  canine  and  incisor  teeth  of  the  superior 
maxilla,  ascends  obliquely  forwards,  and  is  inserted  into  the 
integuments  of  the  upper  lip,  and  into  the  fibro-cartilage  of 
the  septum  and  ala  nasi ;  use,  to  press  the  lip  against  the 
anterior  teeth,  and  even  to  draw  it  under  these,  also  to  de- 

Eress  the  septum  and  ala  nasi.    It  is  covered  by  the  levator 
ibii,  orbicularis  oris,  and  mucous  membrane,  and  it  lies 
upon  the  bone. 

DEPRESSOR  ANGULI,  vel  TRIANGULARIS  ORIS,  flat  and  trian- 
gular, apex  above,  situated  at  the  lower  part  of  the  face ; 
arises  broad  and  fleshy  from  the  external  oblique  line  on 
the  outer  side  of  the  lower  jaw,  which  extends  from  the  an- 
terior edge  of  the  masseter  muscle  to  the  mental  foramen ; 
the  fibres  ascend  converging,  and  are  inserted  narrow,  into 
the  commissure  of  the  lips,  where  the  fibres  are  continuous 
or  mingled  with  the  orbicularis,  zygomatic,  and  levator 
anguli  muscles :  its  name  denotes  its  use.  This  muscle  is 
covered  by  the  skin,  some  of  its  fibres  are  continuous  with 
those  of  the  platysma  myoides ;  it  overlaps  the  buccinator 
and  the  following  muscle.  The  facial  artery  bounds  its 
external  edge  and  separates  it  from  the  masseter. 

DEPRESSOR  LABII  INFERIORIS,  vel  QUADRATUS  MENU,  broad 
and  somewhat  square,  arises  from  the  side  and  front  of  the 
lower  maxilla,  just  above  its  basis,  internal  to  the  last,  and 
continues  as  far  forwards  as  the  middle  line ;  the  fleshy 
fibres,  intermixed  with  fat,  ascend  a  little  inwards,  decus- 
sating with  some  of  the  opposite  muscle,  and  are  inserted 


DUBLIN    DISSECTOR.  13. 

into  half  of  the  lower  lip,  and  into  the  orbicularis  oris ;  its 
name  denotes  its  use.  This  muscle  is  covered  by  the  skin* 
and  externally  by  the  depressor  anguli  oris,  it  lies  on  the 
bone,  the  mental  nerves  and  vessels,  orbicularis  oris  muscle, 
and  mucous  membrane :  by  separating  this  from  the  last 
muscle,  the  mental  nerve  and  vessels  are  exposed;  the 
fibres  are  parallel,  and  many  are  continuous  with  those  of 
the  platysma ;  this  muscle  is  difficult  to  dissect,,  its  inner 
fibres  being  pale  and  intermixed  with  fat,  it  is  not  unlike 
the  structure  of  the  tongue :  it  conceals  the  following 
muscle. 

LEVATOR  LABII  INFERIORIS,  vel  MENTI,  is  best  exposed  by 
turning  down  the  upper  lip»  and  raising  the  mucous  mem- 
brane by  the  side  of  the  frasnum ;  arises  from  the  alveoli  oi 
the  incisor  teeth  of  the  lower  maxilla,  by  the  side  of  the 
symphysis ;  the  fibres  diverge  as  they  descend  obliquely 
forwards  between  the  mucous  membrane  and  the  depressor 
labii  inferioris ;  inserted  into  the  integument  of  the  chin ; 
use,  to  elevate  the  chin  and  lower  lip ,  this  muscle  is  anal- 
ogous to  the  depressor  of  the  upper  lip.  It  assists  in  form- 
ing the  prominence  of  the  chin. 

ORBICULARIS  ORIS,  surrounds  the  opening  of  the  mouth ; 
consists  of  two  fleshy  fasciculi,  one  for  either  lip,  placed 
between  the  skin  and  mucous  membrane,  and  constituting 
the  chief  thickness  of  the  lip ;  these  fasciculi  decussate 
each  other  at  the  commissures,  and  intermix  with  all  the 
muscles  inserted  there ;  use,  to  approximate  the  lips  and 
regulate  their  motions  in  the  acts  of  speaking  and  breath- 
ing, and  to  oppose  the  actions  of  the  several  muscles  which 
are  inserted  into  the  commissures;  it  can  also  close  the 
lips  with  different  degrees  of  force,  as  in  the  processes  of 
suction,  mastication,  and  deglutition.  This  muscle  has  no. 
bony  attachment ;  its  fibres  are  blended  with  fat,  particu- 
larly on  their  cutaneous  surface ;  internally  they  are  more 
smooth  and  distinct :  they  adhere  most  closely  to  the  skin, 
and  throw  it  into  numerous  minute  ruga>,  when  they  con- 
tract. 

BUCCINATOR,  is  broad,  thin,  and  somewhat  square,  situated 
between  the  two  alveolar  arches,  it  forms  the  inner  side  of 
the  cheek,  and  the  lateral  boundary  of  the  mouth,  and  lies 
close  to  the  mucous  membrane  of  the  latter ;  arises  poste- 
riorly from  the  two  last  alveoli  of  the  superior  maxilla,  as 
far  back  as  the  pterygoid  process,  from  the  external  sur- 
face of  the  posterior  alveoli  of  the  lower  maxilla,  as  far 
back  as  the  coronoid  process,  and  forms  a  strong  aponew- 
rosis,  named  the  intermaxillary  ligament,  which  extends 
from  the  extremity  of  the  internal  pterygoid  plate  to  the 
root  of  the  coronoid  process,  and  which  affords  attachment 

2 


14  DUBLIN    DISSECTOR, 

to  the  superior  constrictor  of  the  pharynx  posteriorly,  and 
to  the  buccinator  anteriorly.  From  these  three  origins  the 
fibres  pass  horizontally  forwards,  converging  a  little,  and 
are  inserted  into  the  commissure  of  the  lips,  where  they  in- 
termix with  those  of  the  orbicularis,  and  of  the  other  mus- 
cles at  the  angle  of  the  mouth.  Use,  to  press  the  cheek 
against  the  teeth,  so  as  to  bruise  and  push  the  food  between 
them,  and  to  diminish  the  cavity  of  the  mouth,  as  in  masti- 
cation and  deglutition ;  it  is  also  much  engaged  in  the  arti- 
culation of  certain  expressions,  as  well  as  in  filling  wind 
instruments ;  it  can  also  retract  the  commissure  of  the  lips. 
The  buccinator  is  covered  by  a  considerable  quantity  of 
fat,  which  separates  it  from  the  coronoid  process  of  the 
lower  maxilla,  and  from  the  insertion  of  the  temporal  mus- 
cle, this  fat  often  extends  in  the  form  of  large,  soft,  round 
masses  beneath  the  masseter  muscle  ;  it  is  also  covered  by 
the  zygomatic,  the  depressor  anguli  oris  and  platysma 
muscles,  and  by  the  facial  vessels ;  several  branches  of  the 
facial  artery  and  vein,  and  of  the  seventh  and  fifth  pairs  of 
nerves,  ramify  on  its  surface ;  it  lies  on  the  mucous  mem- 
brane, and  on  a  number  of  small  round  mucous  glands 
called  buccal ;  it  is  perforated  near  its  superior  posterior 
third  by  the  duct  of  the  parotid  gland,  opposite  the  third 
superior  molar  tooth. 

The  deep  muscles  of  the  face,  which  are  connected  with 
the  lower  maxilla,  and  which  are  employed  in  the  process 
of  mastication,  are  the  masseter,  temporal,  internal,  and 
external  pterygoid  of  each  side :  previous  to  dissecting 
these,  the  student  should  examine  the  situation  and  con- 
nexions of  the  parotid  gland,  the  chief  of  the  salivary 
glands.  There  are  six  salivary  glands,  three  on  each  side, 
the  parotid,  submaxillary,  and  sublingual. 

The  salivary  glands,  together  with  the  lachrymal,  mam- 
mary, and  pancreas,  are  commonly  called  conglomerate 
glands,  in  contradistinction  to  the  absorbent,  or  lymphat- 
ic, or  conglobate  glands;  this  term,  however,  is  by  no 
means  distinct  or  definite,  for  other  glands,  viz.  the  liver 
and  kidney,  are  equally  conglomerate,  though  not  so  ob- 
viously such.  The  general  arrangement  of  the  glandular 
system  we  propose,  is  into  two  orders,  the  Absorbent  and 
Secreting ;  the  absorbent,  or  lymphatic,  or  conglobate,  will  be 
noticed  hereafter :  the  secreting  order  may  be  divided  into 
two  classes,  viz.  the  simple  and  the  complex ;  the  simple 
are  the  numerous  glands  which  are  attached  very  general- 
ly to  the  mucous  membranes ;  the  compound  secreting  or 
conglomerate  glands,  are  the  lachrymal,  salivary,  mam- 
mary, pancreas,  liver,  kidney,  prostate,  and  testis.  There 
is  no  evidence  for  considering  the  pinaeal,  pituitory,  thy- 


DUBLIN    DISSECTOR.  15 

roid,  thymus,  or  supra-renal  bodies,  or  the  spleen  and 
ovaries  as  true  glands. 

[Here,  as  in  most  of  the  systems  of  anatomy  tbe  term  gland  is 
applied  to  two  classes  of  organs  which  differ  essentially  in  their 
structure,  their  relations,  and  their  functions,  viz.  the  glands  proper 
and  the  lymphatic  ganglia.  If  we  examine  the  works  on  general  anato- 
my, we  shall  find  that  the  glandular  tissue  is  defined  as  consisting  of 
an  assemblage  of  secreting  organs,  more  or  less  globular  in  form, 
and  having  an  excretory  duct  lined  with  mucous  membrane,  which 
terminates  directly  or  indirectly  upon  the  surface  of  the  body  :  this 
being  the  case,  it  is  evident  that  in  the  present  state  of  our  knowledge, 
the  lymphatic  or  absorbent  bodies  cannot  be  brought  under  the  head 
of  glands ;  it  is  therefore  better  to  drop  the  term  as  applied  to  them, 
because  it  leads  to  error  as  to  their  functions,  &c.,  and  substitute 
the  term  ganglion,  which  is  used  by  some  writers.  Accordingly,  in 
revising  this  book  the  tenms  ganglion  and  ganglia  are  substituted 
for  gland  and  glands,  whenever  used  as  referring  to  the  lymphatic 
bodies.  The  glands  proper,  as  stated  above,  may  be  divided  into 
simple  and  compound;  and  the  compound  may  be  again  divided  into 
conglobate  and  conglomerate  :  by  conglobate  we  mean  glands  com- 
posed of  an  assemblage  of  glandular  particles  united  in  jnass  by 
cellular  tissue,  and  having  a  common  and  distinct  sheath  or  .covering, 
as  the  liver :  by  conglomerate  we  mean  an  assemblage  of  small 
conglobate  glands,  united  together  by  cellular  tissue,  and  connected 
iby  an  indistinct  covering  of  loose  cellular  substance,  the  whole  organ 
presenting  an  uneven  lobulated  appearance,  instead  of  being  smooth, 
and  the  excretory  ducts  of  each  lobule  terminating  in  a  common 
duct,  as  the  pancreas,  &c.] 

The  salivary  glands,  including  the  lachrymal,  the  mam- 
mary, and  the  pancreas,  all  correspond  in  certain  charac.- 
ters,  in  which,  also,  they  differ  from  other  secreting  glands : 
they  are  all  symmetrical,  except  the  pancreas,  which 
however,  is  attached  to  the  digestive  organs,  the  chief  ap- 
paratus of  organic  life,  but  one  in  which  no  symmetry  is 
observed :  they  are  of  a  pale  grey  colour,  with  a  slight  red- 
dish tint;  the  virgin  mammary  gland  is  almost  white; 
they  have  no  perfect  capsule,  except  the  mammary,,  and 
that,  though  perfect,  is  very  thin  and  loose :  their  form 
and  size  are  not  accurately  defined,  two  or  more  being 
sometimes  connected;  they  are  very  irregular  in  these 
respects  ;  their  texture  is  loose,  that  is,  they  consist  of 
grains  which  are  but  loosely  connected  by  cellular  tissue 
and  vessels  into  small  lobules,  and  these  into  larger  lobes: 
the  granules  themselves  are  very  firm  and  compact:  they 
are  all  well  supplied  with  nutrient  vessels,  the  arteries 
ramify  minutely  before  they  enter  them,  which  they  do 
at  all  parts  of  their  surface,  and  not  at  any  particular 
fissures,  as  in  the  liver  and  kidney ;  the  transit  of  the 
carotid  and  facial  ^arteries  through  the  parotid  and  sub- 


16  DUBLIN    DISSECTOR. 

maxillary  glands  is  not  an  exception  to  this  statement : 
the  veins  in  like  manner  escape  at  different  parts,  and 
enter  the  neighbouring  vessels:  their  excretory  ducts  in 
some  unite  into  one  vessel,  which  proceeds  to  its  destina- 
tion, but  in  others,  as  in  the  lachrymal,  mammary,  and 
sublingual,  they  continue  separate  to  the  surface.  In  no 
case  is  there  any  perfect  reservoir  to  delay  or  retain  the 
secretion,  as  in  the  case  of  the  liver  and  -the  gall  bladder, 
the  kidney  and  the  vesica ;  the  lachrymal  sac  cannot  be 
considered  as  such  :  they  are  largely  supplied  with  nerves, 
and,  except  the  filaments  of  the  sympathetic,  which  ac- 
company the  vessels,  these  are  derived  from  the  spinal 
and  cerebral  system ;  the  pancreas  is  an  exception  to  this 
rule:  not  only  cellular  tissue  in  abundance,  but  even 
adipose  enter  into  their  composition :  they  are  in  close 
connexion  with  the  lymphatic  or  absorbent  system,  nu- 
merous lymphatic  vessels  pervade  them,  and  lymphatic 
ganglia  are  in  their  close  vicinity,  and  'occasionally  even 
imbedded  in  their  substance.  In  many  -of  these  characters, 
the  salivary  glands  form  a  remarkable  contrast  with  the 
other  complex  secreting  glands,  which  "will  more  fully  ap- 
pear when  the  latter  come  under  our  notice.  All  the  se- 
creting glands,  simple  as  well  as  compound,  are  subject  to 
many  diseases  ;  these  will  be  noticed  in  the  account  of  the 
individual  glands. 

The  PAROTID  GLAND  is  the  largest  of  these  conglomerate 
glands,  it  derives  its  name  from  its  proximity  to  the  ear ; 
it  is  exposed  by  dissecting  off  the  integuments  and  some 
fibres  of  the  platysma,  also  a  dense  fascia  which  covers 
and  adheres  to  it ;  this  fascia  is  continued  from  that  of  the 
neck,  spreads  over  the  gland,  is  closely  connected  to  the 
cartilaginous  part  of  the  meatus  auditorius,  and  sends  nu- 
merous processes  into  the  gland  in  every  direction,  serving 
to  separate  its  lobules,  and  to  conduct  the  different  vessels 
through  its  substance.  The  parotid  gland  is  not  of  any 
regular  figure,  by  some  it  is  considered  pyramidal,  the 
apex  above,  the  base  directed  outwards  and  downwards ; 
by  others,  (the  upper  end  being  more  developed,)  an  ir- 
regular square  ;  as  such  we  shall  consider  it,  and,  of  course, 
as  presenting  two  surfaces,  a  superficial  and  a  deep,  and 
four  margins,  a  superior,  inferior,  anterior,  and  posterior  : 
it  occupies,  together  with  some  other  important  parts,  that 
deep  excavation  on  the  side  of  the  face  between  the  lower 
jaw  and  the  auditory  meatus,  it  also  extends  into  the  small 
region  of  the  neck,  named  the  posterior  digastric  space ; 
it  is  bounded  above  by  the  zygoma,  below  by  a  line  drawn 
from  the  angle  of  the  jaw  to  the  mastoid  process,  posteri- 
orly by  the  meatus  auditorius,  the  mastoid  process,  and 


DUBLIN    DISSECTOR.  17 

•sterno-mastoid  muscle,  and  anteriorly  by  the  masseter 
muscle,  the  posterior  third  of  which  it  overlaps.  The  ex- 
ternal surface  is  pale,  flat,  or  slightly  convex,  in  this  re- 
spect, however,  differing  in  different  persons,  as  it  also  does 
in  superficial  extent ;  probably  the  absence  of  a  regular 
.capsule  may  in  some  measure  account  for  this  diversity ; 
the  anterior  and  inferior  margins  are  the  least  defined,  are 
irregular  in  their  extent,  in  some  they  considerably  exceed 
the  ordinary  bounds  ;  the  superior  border  is  limited  by  the 
attachment  of  the  fascia  to  the  zygoma,  and  the  posterior 
is  resisted  by  the  meatus  of  .the  ear,  and  by  the  sterno- 
mastoid  muscle. 

The  connexions  of  the  deep  surface  may  be  examined 
after  the  course  of  the  excretory  duct,  and  of  the  several 
vessels  and  nerves  which  pass  through  the  gland,  shall 
have  been  exposed.  The  Parotid  or  Steno's  duct  arises  from 
its  anterior  superior  border,  and  is  formed  by  the  union  of 
numerous  small  vessels,  which  issue,  each,  from  one  of  the 
granulations  of  the  gland  ;  it  passes  forwards  over  the 
masseter  muscle  about  an  inch  below  the  zygoma,  parallel 
to  a  line  drawn  from  the  tube  of  the  ear  to  midway  be- 
tween the  commissure  of  the  lips  and  the  root  of  the  nose ; 
it  winds  round  the  anterior  e4ge  of  the  masseter,  beneath 
the  zygomatic  muscles  and  through  a  quantity  of  soft 
adeps,  pierces  the  buccinator,  and  opens  through  the  mu- 
cous membrane  of  the  mouth  by  a  very  small  hole  oppo- 
site the  second  or  third  superior  molar  tooth,  about  half 
an  inch  from  the  junction  of  the  cheek  with  the  gum.  Be- 
tween the  duct  and  the  zygoma,  a  small,  smooth,  glandu- 
lar mass  is  frequently  found ;  it  appears  like  a  detached 
lobe  of  the  parotid,  it  is  named  the  soda  parotidis ;  from  the 
lower  and  anterior  part  of  this  process,  a  small  duct  pro- 
ceeds, which  after  a  short  course  unites  with  the  duct  of 
Steno ;  in  some  this  duct  opens  distinctly  into  the  mouth. 
The  transverse  artery  of  the  face,  and  several  branches  of 
the  facial  nerve,  accompany  this  vessel,  and  in  general  the 
artery  is  superior  to  it,  while  the  nerves  wind  around  it. 
This  duct  appears  much  larger  than  its  calibre  really  is ; 
it  is  formed  of  two  coats,  the  external,  white,  fibrous,  and 
dense,  commences  beyond  the  anterior  edge  of  the  gland, 
and  ends  at  the  buccinator  muscle  ;  and  the  internal,  a  fine, 
delicate,  mucous  membrane,  is  continuous  with  that  lining 
the  mouth  :  the  canal  is  larger  at  the  commencement  and 
outside  the  buccinator  than  in  the  intervening  space,  or  at 
the  orifice  in  the  mouth. 

The  parts  which  pass  through  this  gland  are  the  exter- 
nal carotid  artery  and  several  of  its  branches,  with  their 
accompanying  veins,  and  branches  of  the  inferior  maxil- 
2* 


18  DUBLIN    DISSECTOR. 

lary  and  cervical  nerves,  also  the  plexus  of  the  portio 
dura,  or  facial  nerve.  The  first  or  most  superficial  of 
these  parts  is  the  ascendens  colli  nerve,  or  the  superficialis 
colli  or  auricularis,  it  enters  the  gland  near  its  lower  bor- 
der, and  is  lost  chiefly  in  communicating  with  the  portio 
dura ;  this  last-named  nerve  escapes  from  the  cranium  by 
the  stylo-mastoid  foramen,  enters  the  gland  at  its  posterior 
inferior  part,  passes  forwards  and  upwards  through  it,  and 
forms  in  its  substance  the  remarkable  plexus,  parotida an,  or 
pes  anserina,  which  crosses  superficial  to  the  external  car- 
otid artery,  and  then  separates  into  its  two  great  divisions, 
the  superior  and  inferior ;  a  small  portion  of  the  gland  in- 
tervenes between  it  and  the  vessels.  The  branch  of  the 
inferior  maxillary  nerve,  which  traverses  the  gland  is  the 
temporo-auricular,' which  will  be  found  between  the  neck  of 
the  lower  jaw  and  the  meatus  auditorius,  about  half  an 
inch  above,  but  much  .deeper  than  the  portio  dura,  with 
which  it  communicates,  and  for  which  it  is  sometimes 
mistaken. 

The  external  carotid  artery  will  be  found  to  enter  the  low- 
er border  of  the  gland,  near  its  deep  surface,;  as  it  ascends 
it  is  crossed  by  the  portio  dura,  and  becomes  much  more 
superficial,  its  posterior  auricular  branch  borders  the  low- 
er and  back  part  of  the  gland,  the  temporal  ascends  through 
it,  the  internal  maxillary  is  deeply  imbedded  in  it  in  its 
course  forwards  and  inwards,  the  transverse  facial  artery 
also  traverses  it  in  a  direction  forwards,  and  it  also  gives 
off  numerous  branches  to  the  granules  of  the  gland  and  to 
the  ear.  The  veins  corresponding  to  these  arteries  also 
pass  through  this  organ  ;  the  temporal  and  internal  max- 
illary, by  their  confluence,  which  i-s  superficial  to  the  ex- 
ternal carotid  artery,  and  very  rarely  to  the  portio  dura 
also,  forms  the  external  jugular  vein,  which  descends  through 
the  gland,  and  becomes  then  superficial  in  the  neck.  Sev- 
eral lymphatic  vessels  .and  ganglia  are  connected  with  the 
parotid,  particularly  to  its  inferior  border ;  generally  one 
or  two  small  ganglia  .may  be  found  imbedded  in  its  sub- 
stance, in  front  of  the  meatus  auditorius,  just  where  its 
cartilage  is  deficient. 

Now  divide  the  parotid  duct,  raise  off  the  gland  from 
the  masseter  muscle,  and  from  .the  ramus  of  the  jaw,  and 
observe  its  'several  deep-seated  connexions. 

The  deep  or  posterior  surface  of  the  gland  is  very  ir- 
regular, it  covers  the  .posterior  third  of  the  masseter,  also 
the  ramus  of  the  jaw,  behind  which  it  sinks,  and  fills  the 
deep  excavation  between  this  bone  and  the  ear,  envelops 
the.styloid  process  of  the  temporal  bone  and  the  muscles 
which  arise  from  it,  and  it  touches  the  internal  carotid 


DUBLIN    DISSECTOR.  19 

artery,  jugular  vein,  and  the  large  nerves  connected  with 
these  vessels ;  it  also  fills  the  posterior  part  of  the  glenoid 
cavity  in  the  temporal  bone,  and  adheres  to  the  capsular 
ligament  of  the  maxilla,  inferiorly  it  is  wedged  in  between 
the  internal  pterygoid,  digastric,  and  styloid  muscles. 

The  styloid  process  is  in  some  cases  so  involved  in  it  as 
to  appear  to  divide  the  gland  into  a  superficial  and  a  deep 
lobe,  the  latter  will  then  be  deeper  than  this  process  and 
in  close  connexion  with  the  great  cervical  nerves  and  ves- 
sels :  a  portion  of  the  gland  will  also  be  found  to  accom- 
pany the  internal  maxillary  artery  between  the  ramus  of 
the  jaw  and  its  internal  lateral  ligament ;  this  touches  the 
inferior  maxillary  nerve,  and  in  many  instances  extends 
into  the  fatty  space  between  the  two  pterygoid  muscles, 
where  it  swells  out  to  a  considerable  size,  so  as  to  appear 
like  a  distinct  lobe  connected  to  the  body  of  the  gland  by 
a  narrow  neck. 

The  parotid  gland  is  composed  of  numerous  small  gran- 
ulations, united  together  by  cellular  tissue,  by  branches  of 
blood-vessels  and  nerves,  and  by  the  small  roots  of  its  ex- 
cretory duct.  This  gland  is  subject  to  several  MORBID 
changes,  viz.  inflammation,  or  cynanche  parotidsea,  or 
parotitis,  or  mumps;  abscess;  hypertrophy,  or  scirrhus 
induration,  which  sometimes  requires  extirpation ;  scirr- 
hus, ending  in  cancer  ^  fistula,  the  effect  of  abscess  or 
wound  of  the  .gland  or  duot ;  atrophy,  or  absorption,  this 
latter  condition  is  usually  caused  by  tumors,  lymphatic  or 
encysted,  these  by  degrees  come  to  occupy  the  position  of 
the  gland  and  cause  its  absorption.  -Such  tumors  simulate 
the  enlarged  parotid,  though  essentially  different,  they  ad- 
mit of  more  easy  extirpation  as  they  are  usually  surround- 
ed by  a  capsule,  and  are  nat  traversed  by  the  adjacent 
nerves  and  vessels. 

[This  gland  is  also  the  seat  of  encephaloid  disease,  of  melanosis, 
and  of  fatty  degeneration  ;  salivary  calculi  also  occur  sometimes  in  its 
ducts  :  but  the  mumps  is  the  disease  to  which  it  is  most  subject. 
This  is  an  infectious  disease,  usually  occuring  but  once,  attacking 
young  persons  and  on  both  sides,  and  not  (infrequently  presenting  a 
metastasis  in  the  male  to  the  testicle,  and  in  the  female  to  the  breast : 
several  cases  are  reported  of  the  successful  extirpation  of  this  organ, 
in  this  country,  by  Drs.  Bush,  McClellan  and  Parker.] 

Next  clean  the  masseter  muscle. and  'the  temporal  apo- 
neurosis. 

MASSETER:  the  greater  part  of  this  muscle  is  superficial, 
it  is  thick  and  strong,  covers  <the  ramus  and  angle  of  the 
jaw,  and  consists  of  two  portions,  one  anterior,  which  is  the 
larger,  the  other  posterior,  these  decussate  each  other ;  the 
anterior  arises  chiefly  tendinous  from  the  superior  maxilla 


20  DUBLIN    DISSECTOR. 

where  it  joins  the  malar  bone,  also  from  the  inferior  edge 
of  the  latter,  the  fibres  pass  downwards  and  backwards 
and  are  inserted  fleshy  into  the  outer  surface  of  the  angle 
of  the  lower  maxilla.  The  posterior  or  deep  portion  of  the 
muscle  arises  chiefly  fleshy  from  the  edge  of  the  malar 
bone  and  from  the  zygomatic  arch,  as  far  back  as  the  gle- 
noid  cavity ;  the  fibres  descend,  some  vertically,  others 
obliquely  forwards,  and  are  inserted  chiefly  tendinous,  into 
the  external  side  of  the  angle  and  ramus  of  the  /jaw,  as  high 
as  the  coronoid  process ;  thus  the  two  layers  of  this  mus- 
cle are  contrasted  both  in  the  direction  of  their  fasciculi, 
as  well  as  in  the  relative  position  of  their  tendinous  and 
fleshy  fibres.  Use,  if  both  portions  of  both  muscles  act 
together,  they  will  elevate  the  lower  jaw ;  if  the  anterior 
portions  only  of  opposite  sides  act  together,  they  can  carry 
the  jaw  forwards  and  upwards  ;  and  if  the  posterior  alone, 
they  can  move  it  backwards  and  upwards ;  if  the  super- 
ficial layer  of  one  side  act  alone  it  can  rotate  the  chin  to 
the  opposite  side,  and  if  the  deep  layer  only  act  it  can 
rotate  it  to  its  own  side.  Thus  the  masseter  muscles  of  op- 
posite sides,  by  the  alternate  action  of  their  different  por- 
tions, are  powerful  agents  in  mastication ;  they  not  only 
cause  the  division  of  the  food  by  the  direct  elevation  and 
pressure  of  the  lower  maxilla  against  the  upper,  but  they 
can  also  triturate  it,  by  the  great  lateral  motion  of  the  jaw 
which  their  different  laminse  are  capable  of  exercising  al- 
ternately. The  masseter  is  covered  by  the  skin,  some 
fibres  of  the  platysma  and  orbicularis  palpebrarum,  a  por- 
tion of  the  parotid  gland,  and  its  excretory  duct,  by  the 
transverse  facial  vessels  and  nerves,  and  by  the  zygomatic 
muscles.  It  lies  on  the  ramus  of  the  jaw,  and  conceals  the 
insertion  of  the  temporal,  and  the  origin  of  the  buccinator, 
from  which  it  is  separated  by  a  great  quantity  of  fat ;  the 
superficial  layer  covers  the  deep  one,  except  a  small  por- 
tion of  the  latter  near  the  articulation  of  the  maxilla; 
strong  tendinous  septa  pass  from  the  surface  of  this  muscle 
through  its  substance,  and  adhere  to  the  ramus  of  the  bone 
beneath. 

The  masseter  by  its  superficial  layer  may  assist  in  dis- 
locating the  lower  jaw,  if  it  suddenly  contract  when  the 
chin  is  much  depressed.  This  muscle,  like  the  temporal, 
appears  to  be  much  under  the  influence  of  the  nervous 
system  and  extremely  irritable,  it  is  very  seldom  in  a  state 
of  paralysis,  even  when  the  superficial  muscles  of  the  face 
are  so ;  whereas  in  tetanus  it  is  in  a  state  of  almost  rigid 
contraction :  in  rigors  also,  or  when  exposed  to  much  cold 
these  muscles  evince  their  sympathy  with  the  general  sys- 


DUBLIN    DISSECTOR.  21 

tern,  the  will  loses  all  control  over  them,  they  act  irregu- 
larly, and  produce  the  "  chattering  of  the  teeth." 

TEMPORALIS,  is  concealed  by  the  temporal  aponeurosis, 
the  zygoma,  and  the  masseter,  it  tills  the  temporal  fossa,  is 
thin  and  broad  above,  thick  and  narrow  below.  The  apo- 
neurosis is  very  strong  and  tense,  of  a  semicircular  form, 
adhering  by  its  superior  convex  border  to  the  semicircular 
ridge  on  the  side  of  the  cranium,  which  extends  from  the 
external  angular  process  of  the  frontal  along  the  parietal 
as  far  back  as  the  mastoid  process  of  the  temporal  bone, 
and  by  its  inferior  straight  margin  to  the  upper  edge  of  the 
zygoma,  and  to  the  superior  posterior  edge  of  the  malar 
bone.  This  fascia  is  thin  above,  the  muscle  appears 
through  it,  inferiorly  it  is  thick  and  opaque ;  it  consists  of 
two  laminae  which  are  very  distinct  inferiorly,  some  fat 
being  interposed ;  the  fibres  composing  the  external  layer, 
run  longitudinally,  those  of  the  internal,  irregularly.  The 
temporal  aponeurosis  confines  the  muscle  in  its  place,  and 
gives  additional  origin  to  its  fibres.  Separate  the  masseter 
from  its  superior  attachment,  divide  with  the  saw  the  zy- 
goma at  either  end,  and  elevate  it  together  with  the  lower 
part  of  the  temporal  fascia ;  the  temporal  muscle  will  be 
thus  exposed.  It  consists  of  two  laminse,  the  superficial  is 
thin,  but  the  deep  layer  is  very  thick ;  an  aponeurosis  or 
tendon  is  between  these.  It  arises  from  all  the  side  of  the 
cranium  beneath  the  semicircular  ridge  on  the  parietal 
bone,  and  from  all  the  temporal  fossa  and  fascia;  the 
fibres  therefore  are  attached  internally  to  the  parietal, 
frontal,  and  temporal  bones,  also  to  the  sphenoid  as  low 
down  as  the  crest  at  the  root  of  its  great  wing,  which  crest 
separates  the  temporal  from  the  zygomatic  fossa;  ante- 
riorly to  the  malar  bone,  and  externally  to  the  inside  of  the 
temporal  fascia,  and  to  the  zygomatic  arch.  The  fleshy 
fibres  all  descend  converging ;  the  middle  nearly  vertical.; 
the  anterior  with  a  little  obliquity  backwards ;  the  poste- 
rior, which  are  very  long,  pass  nearly  horizontally  for- 
wards, over  a  smooth  surface  at  the  root  of  the  zygoma, 
and  the  inferior  fibres,  which  arise  from  the  crest  on  the 
sphenoid  bone,  are  very  short,  and  pass  transversely  out- 
wards. 

Inserted  by  a  strong  tendon  into  the  coronoid  process  of 
the  inferior  maxilla ;  it  nearly  surrounds  that  process,  ex- 
cept on  its  outer  side,  and  is  continued  along  its  fore-part 
as  far  as  the  last  molar  tooth.  Use,  to  raise  the  lower  jaw 
when  the  whole  muscle  acts ;  the  anterior  fibres  may  also 
advance  the  jaw,  and  the  posterior  long  fibres  can  draw  it 
backwards,  while  the  inferior  transverse  fibres,  which  are 
nearly  parallel  to  the  external  pterygoid  muscle,  may 


22  DUBLIN    DISSECTOR. 

assist  in  its  lateral  and  rotatory  motions ;  this  muscle,  par- 
ticularly its  posterior  portion,  is  the  greatest  security  which 
the  jaw  possesses  against  dislocation,  as  it  directly  opposes 
the  external  pterygoid  muscles  which  tend  to  advance  the 
jaw,  and  to  place  its  condyles  on  the  zygomatic  eminences. 
The  temporal  muscle  is  covered  by  the  integuments,  oc- 
cipito-frontalis,  superficial  temporal  vessels  arid  nerves, 
temporal  fascia,  zygoma,  masseter,  orbicularis  palpebra- 
rum,  and  auricular  muscles :  it  lies  on  the  side  of  the  cra- 
nium, and  covers  all  the  bones  which  compose  the  tempo- 
ral fossa,  also  the  deep  temporal  vessels,  and  part  of  the 
external  pterygoid  and  buccinator  muscles,  from  which  it 
is  separated  by  much  fat. 

Wounds  of  the  temporal  aponeurosis  are  often  attended 
with  serious  effects,  the  severe  pain  and  tension  interfere 
with  the  action  or  extension  of  the  muscle,  the  mouth  can 
scarcely  be  opened,  nor  can  mastication  be  performed 
without  great  difficulty  ;  these  symptoms  simulate  tetanus, 
from  which,  however,*  they  may  be  distinguished  by  atten- 
tion to  the  countenance  and  to  the  state  of  the  muscles  of 
the  opposite  side  :  suppuration  beneath  this  fascia  is  both 
troublesome  and  dangerous  ;  injury  to  it  should  be  avoided 
in  arteriotomy.  In  vital  powers  this  muscle  is  analogous 
to  the  masseter,  it  is  largely  supplied  with  nerves  from  the 
same  source.  Remove  the  temporal,  masseter,  and  bucci- 
nator muscles,  also  the  zygomatic  arch,  saw  or  break  off, 
low  down,  the  coronoid  process,  dissect  away  some  fat, 
and  the  pterygoid  muscles  will  be  exposed,  the  dissection 
of  which  may  be  still  further  facilitated  by  dividing  the 
side  of  the  lower  jaw  in  front  of  the  insertion  of  the  masse- 
ter, as  the  angle  and  ramus  of  the  jaw  can  then  be  moved 
backwards  and  forwards. 

The  pterygoid  muscles  are  situated  very  deep  behind  the 
ramus  of  the  lower  jaw,  they  are  two  in  number,  internal 
and  external,  their  names,  however,  only  refer  to  their 
origins  from  the  external  pterygoid  plate  of  the  sphenoid 
bone,  for  neither  are  attached  to  the  internal  plate ;  that 
which  is  called  external  is  nearer  to  the  median  line  of  the 
body,  the  internal  is  more  superficial,  and  therefore  first 
met  with  in  dissection. 

[This  muscle  is  usually  described  as  arising  from  the  internal  ptery- 
goid plate  of  the  sphenoid  bone.] 

PTERYGOIDEITS  INTERNUS  is  strong  and  thick,  placed  on 
the  inner  side  of  the  ramus  of  the  jaw,  parallel  and  very 
similar  to  the  superficial  layer  of  the  masseter  muscle  ex- 
ternally ;  it  arises  tendinous  and  fleshy  from  the  inner  side 
of  the  external  pterygoid  plate,  and  pterygoid  process  of 


DUBLIN    DISSECTOR.  23 

the  palate  bone ;  it  fills  the  greater  part  of  tne  pterygoid 
fossa,  descends  obliquely  outwards  and  backwards,  and  is 
inserted  tendinous  and  fleshy  into  the  inner  side  of  the 
angle  of  the  jaw,  and  into  the  rough  surface  above  it. 
Use,  if  the  muscles  of  opposite  sides  act  together,  to  draw 
forwards  and  to  elevate  the  jaw,  thus  co-operating  with  the 
superficial  layers  of  the  masseter  muscles ;  if  alternately, 
they  can  rotate  it,  each  moving  the  jaw  laterally,  so  as  to 
turn  it  to  the  opposite  side.  This  muscle  is  larger  than  the 
external  pterygoid,  inferior  and  external  to  which  it  lies. 
Above,  the  tensor  palati,  superior  constrictor,  and  below 
the  submaxillary  gland  are  in  contact  with  its  internal 
surface :  the  ramus  of  the  jaw  is  external  to  it,  and  sepa- 
rated from  it  by  the  dental  nerve,  the  internal  maxillary 
artery  and  its  primary  branches,  which  are  protected  from 
the  pressure  of  the  muscle  by  the  internal  lateral  ligament 
of  the  jaw :  the  lower  extremity  of  this  muscle  is  very 
superficial,  lying  between  and  in  contact  with  the  parotid 
and  submaxillary  glands :  the  upper  extremity  or  origin 
is  separated  by  the  tendon  of  the  tensor  palati  muscle  from 
the  internal  pterygoid  plate,  it  is  concealed  by,  and  lies 
deeper  than  that  of  the  external  pterygoid  muscle. 

PTERYGOIDEUS  EXTERNUS  is  short  and  triangular,  the  base 
at  the  pterygoid  process,  the  apex  at  the  condyle,  placed 
at  the  lower  part  of  the  temporal  fossa,  it  arises  broad  and 
fleshy  from  the  outer  side  of  the  external  pterygoid  plate, 
from  the  crest  on  the  root  of  the  great  wing  of  the  sphenoid, 
(which  divides  the  temporal  from  the  zygomatic  fossa,)  and 
from  the  back  part  of  the  tuberosity  of  the  superior  maxilla ; 
the  fibres  pass  outwards  and  backwards,  horizontal,  con- 
verging, and  twisted,  are  inserted  tendinous  into  the  anterior 
and  internal  part  of  the  neck  of  the  lower  jaw,  into  the  in- 
terarticular  cartilage  and  inferior  synovial  membrane.  Use, 
when  both  muscles  act,  they  draw  forward  the  jaw,  and  at 
the  same  time  the  interarticular  cartilages,  which  serve  as 
mpveable  or  temporary  sockets  to  prevent  the  condyles 
slipping  off  the  zygomatic  eminences,  when  the  chin  is  ad- 
vanced, or  the  mouth  much  opened ;  if  the  muscle  of  one 
3ide  only  act,  it  will  draw  forward  the  condyle  of  that  side, 
and  turn  the  jaw  to  the  opposite,  and  therefore  when  both 
muscles  act  alternately,  they  will  become  the  principal 
agents  in  triturating  or  grinding  the  food.  The  external 
pterygoid  muscle  lies  in  a  transverse  direction  beneath  the 
base  of  the  cranium,  superior  to  the  internal  pterygoid, 
except  at  its  origin  ;  it  is  internal,  and  inferior  to  the 
temporal  muscle,  and  is  also  concealed  by  the  masseter 
and  the  ramus  of  the  jaw ;  superiorly  it  is  in  contact  with 
the  sphenoid  bone,  posteriorly  with  the  inferior  maxillary 


24  DUBLIN    DISSECTOR. 

nerve  at  its  exit  from  the  foramen  ovale,  while  anteriorly 
and  inferiorly  it  is  in  contact  with  much  adipose  matter, 
and  with  the  principal  branches  of  the  maxillary  artery 
and  nerve.  As  the  external  and  internal  pterygoid  muscles 
arise  so  near  each  other,  and  thence  pass  in  different  direc- 
tions to  their  insertions,  the  external  going  transversely, 
and  the  internal  descending,  they  leave  between  them  a 
triangular  space,  which  contains  a  quantity  of  fat,  a  small 
portion  of  the  parotid  gland,  the  internal  maxillary  artery 
and  vein,  and  the  dental  and  gustatory  branches  of  the  in- 
ferior maxillary  nerve :  as  the  internal  maxillary  artery  is 
about  to  sink  into  the  spheno-maxillary  fossa,  it  sometimes 
passes  between  the  origins  of  the  external  pterygoid  muscle. 

The  condyles  of  the  jaw  enjoy  a  slight  rotation  forwards 
and  downwards  in  the  temporal  articular  cavities,  they  can 
also  advance  a  little  from  the  glenoid  depressions,  and  de- 
scend so  as  to  rest  on  the  zygomatic  tubercles.  The  lower 
jaw  can  be  moved  in  five  "directions ;  depressed,  elevated, 
carried  forwards,  backwards  and  rotated  to  either  side. 
Depression,  whereby  the  cavity  of  the  mouth  is  opened, 
follows  the  simple  relaxation  of  the  elevator  muscles,  as 
when  asleep  in  the  erect  posture,  but  a  greater  depression, 
as  in  yawning,  is  effected  by  the  platisma,  digastric  and 
hyoidean  muscles ;  in  opening  the  mouth  very  wide,  the 
upper  jaw  is  also  raised  by  the  sterno-mastoid  and  digas- 
tric muscles.  Elevation  of  the  lower  jaw  is  performed  by 
the  combined  actions  of  the  temporal,  the  masseter  and  the 
internal  pterygoid  muscles.  The  jaw  is  moved  forwards 
by  the  internal  pterygoid,  the  anterior  fibres  of  the  tempo, 
ral,  the  superficial  layer  of  the  masseter,  and  above  all,  by 
the  external  pterygoid  muscles,  if  these  of  one  side  only 
act  at  a  time,  the  chin  will  not  only  be  advanced,  but  turned 
to  the  opposite  side.  The  jaw  is  carried  backwards  by  the 
deep  layer  of  the  masseter,  and  particularly  by  the  poste- 
rior portion  of  the  temporal  muscle.  In  the  rotatory  mo- 
tions, such  as  occur  in  mastication,  the  chin  is  moved  from 
one  side  to  the  other  by  those  muscles  which  can  advance 
and  draw  back  the  condyles  acting  in  alternate  succession 
on  opposite  sides ;  during  these  rotatory  motions,  the  eleva- 
tors are  also  in  slight  action,  and  thus  the  food  is  perfectly 
comminuted  by  the  -pressure  of  the  latter,  and  by  the  fric- 
tion of  the  former  against  the  uneven  surfaces  of  the  molar 
teeth. 

The  external  pterygoid  muscles  are  the  chief  agents  in 
producing  dislocation  of  the  jaw ;  when  the  mouth  is  widely 
opened,  their  spasmodic  action  may  suddenly  draw  the 
condyles  and  interarticular  cartilages  of  one  or  both  sides 
forwards  off  the  tubercles  into  the  zygomatic  fossae. 


DUBLIN    DISSECTOR.  25 

SECTION  III. 

VESSELS    AND     NERVES    OF    THE    FACE. 

THE  arteries  which  are  to  be  met  with  in  the  dissection 
of  this  region,  are  the  facial  and  the  terminating  branches 
of  the  external  carotid ;  the  nerves  are  branches  of  the 
seventh  and  fifth  pair.  The  facial  artery ',  which  is  a  branch 
or  the  external  carotid,  is  seen  winding  round  the  side  of 
the  jaw,  anterior  to  the  masseter,  and  running  in  a  contort- 
ed course  towards  the  commissure  of  the  lips,  and  thence 
ascending  along  the  side  of  the  nose,  to  the  internal  can- 
thus  of  the  eye  ;  in  this  course  it  sends  off  numerous 
muscular  branches,  the  coronary  arteries  of  the  lips,  the  nasal, 
and  terminates  in  the  angular,  which  communicates  with 
the  ophthalmic  artery,  at  the  inner  side  of  the  orbit.  The 
facial  artery  and  its  divisions  are  accompanied  by  corres- 
ponding veins  :  the  facial  vein  at  the  lower  edge  of  the  jaw 
generally,  but  not  always,  divides  into  two  branches,  one 
superficial  joins  the  external  jugular  vein,  the  other  passing 
deeper  into  the  neck  joins  the  internal  jugular.  The  external 
carotid  artery,  which  is  seen  ascending  from  the  neck  into  the 
parotid  gland,  gives  off  numerous  branches  to  its  several 
lobules,  and  to  the  ear,  and  a  little  below  the  latter  divides 
into  the  transversalis  faciei,  temporalis  superficialis  and 
maxillaris  interna.  The  transverse  artery  of  the  face  [is  usually 
a  branch  of  the  temporal,  and]  crosses  the  masseter 
above,  sometimes  below  the  parotid  duct,  and  divides  into 
small  muscular  branches,  some  of  which  communicate 
with  the  facial  and  infra-orbital  arteries.  The  temporal 
artery  ascends  behind  the  articulation  of  the  maxilla,  on 
the  temporal  aponeurosis,  and  soon  divides  into  an  anterior 
and  posterior  branch ;  the  former  is  directed  towards  the 
forehead,  supplies  the  integuments  and  muscles  there,  and 
communicates  with  the  frontal  branches  of  the  ophthalmic 
artery  ;  the  posterior  division  of  the  temporal  runs  tortu- 
ously upwards,  and  backwards,  divides  into  numerous 
branches,  which  supply  the  integuments  and  inosculate  with 
the  occipital  and  posterior  auris  arteries.  The  internal  max- 
illary artery  is  the  largest  branch  of  the  carotid  ;  it  bends  in 
behind  the  neck  of  the  lower  jaw,  between  the  bone  and  the 
internal  lateral  ligament,  then  runs  tortuously  between  the 
pterygoid  muscles  upwards,  forwards,  and  inwards,  to  the 
lower  and  back  part  of  the  orbit,  where  it  sinks  into  the 
spheno-maxillary  fossa ;  in  this  course  it  sends  off  the 
middle  artery  of  the  dura  mater,  the  inferior  dental,  several 
muscular  branches  to  the  temporal,  masseter,  pterygoid,  and 
3 


26  DUBLIN    DISSECTOR. 

buccinator  muscles,  and  terminates  by  dividing  into  the 
nasal,  descending  palatine,  and  infra-orbital  arteries.  Veins 
accompany  these  different  arteries,  and  in  the  parotid 
gland  we  &nd  the  temporal  and  internal  maxillary  veins 
forming,  by  their  junction,  a  considerable  vessel  called  the 
external  jugular  vein,  which  will  be  afterwards  seen  de- 
scending superficially  in  the  neck.  (For  the  particular 
description  of  the  blood-vessels  of  the  face,  see  the  Ana- 
tomy of  the  Vascular  System.) 

The  nerves  which  are  met  with  in  the  dissection  of  the 
face  are  branches  of  the  seventh  and  fifth  pair  ;  those  of 
the  seventh,  or  the  portio  dura,  have  in  general  a  trans- 
verse direction  from  behind  forwards,  are  remarkable  for 
their  plexiform  arrangement,  and  have  numerous  com- 
munications with  three  branches  of  the  fifth,  which  are 
distributed  chiefly  in  a  vertical  direction  along  the  anterior 
part  of  the  face.  The  portio  dura  escapes  from  the  tem- 
poral bone  through  the  stylo-mastoid  hole,  turns  forwards 
into  the  parotid  gland,  in  which  it  divides  into  two  large 
branches,  w<hich  subdivide  and  join  again  by  several  fila- 
ments forming  the  plexus,  named  pes  anserinus,  or  paroti- 
d&an  plexus,  from  which  several  nerves  proceed ;  some 
ascend  obliquely  forwards  to  the  temple  and  forehead, 
others  pass  transversely  to  the  muscles  of  the  face,  and 
several  descend,  some  parallel,  and  others  inferior  to  the 
side  of  the  lower  maxilla. 

The  fifth  pair  of  nerves  consists  of  three  portions,  viz. 
the  ophthalmic,  superior  maxillary,  and  inferior  maxil- 
lary ;  a  branch  of  each  of  these  divisions  is  met  with  in 
the  dissection  of  the  face.  The  frontal  nerve,  which  is  a 
branch  of  the  ophthalmic,  or  first  division  of  the  fifth,  is 
seen  escaping  from  the  orbit  by  the  superciliary  notch  or 
foramen ;  it  then  ascends  on  the  forehead,  distributes  its 
branches  to  the  integuments  and  muscles,  and  communi- 
cates with  the  portio  dura.  The  infra  orbital  nerve,  which 
is  a  branch  of  the  superior  maxillary,  or  second  division 
of  the  fifth,  is  observed  passing  out  of  the  infra-orbital 
foramen,  behind  the  levator  labii  superioris  alseque  nasi, 
and  dividing  into  several  branches ;  the  most  of  these  pass 
obliquely  downwards,  and  communicate  freely  with 
branches  of  the  seventh  pair.  Through  the  mental  fora- 
men the  mental  nerve  escapes :  this  is  a  branch  of  the  in- 
ferior maxillary,  or  third  division  of  the  fifth  pair  ;  most 
of  its  branches  ascend  to  the  muscles  of  the  lower  lip, 
and  several  communicate  with  the  portio  dura. — (For  the 
more  particular  description  of  the  nerves  of  the  face,  see 
the  Anatomy  of  the  Nervous  System.) 

The  mouth,  fauces,  and  palate,  are  the  parts  of  the  face 


DUBLIN    DISSECTOR.  27 

next  in  order  to  be  examined ;  but  as  these  are  connected 
and  continuous  with  the  pharynx,  and  as  this  organ  can- 
not be  seen  until  the  muscles  of  the  neck  have  been  removed, 
the  student  had  better  postpone  the  dissection  of  the  for- 
rner  until  he  has  become  acquainted  with  the  anatomy  of 
the  latter ;  we  shall  therefore  proceed  next  to  the  disvsection 
of  the  neck. 


CHAPTER   IL 

DISSECTION  OF  THE  NECK. 
SECTION  L 

[The  neck  extends  from  the  base  of  the  cranium  and  lower  jaw 
above,  to  the  sternum  clavicle  and  circumference  of  the  first  rib  be- 
low; it  is  divided  into  an  anterior  and  a  posterior  cervical  region. 
These  regions  are  divided  from  each  other  on  the  superficies  of  the 
neck,  by  the  anterior  edges  of  the  trapezius  muscles ;  in  the  thiek- 
ness  of  the  neck,  they  are  divided  by  a  plane,  corresponding  to  the 
anterior  surface  of  the  cervical  vertebra,  and  thence  reflected  a  little 
forward  on  either  side,  to  the  anterior  edges  of  the  saiaie  muscle.  Of 
these  two  regions,  the  posterior  is  comparatively  of  little  importance 
in  a  surgical  point  of  view,  it  is  occupied  principally  by  muscles  which 
act  upon  the  head  and  neck,  and  by  their  appropriate  vessels  and 
nerves.  On  this  region  it  is  sometimes  necessary  to  operate  for  the 
removal  of  new  formations,  such  as  tumors  of  various  kinds ;  but 
mostly  adipose. 

The  anterior  cervical  region,  on  the  other  hand,  is  of  great  surgical 
importance  in  reference  to  the  occurrence  of  new  formations,  and  also 
in  reference  to  morbid  conditions  of  organs  naturally  situated  there. 
In  the  dissection  of  this  region,  we  find  that  it  has  three  coverings, 
that  it  is  divided  naturally  into  three  triangles,  which  are  again  sub- 
divided, and  that  it  presents  us  with  four  groups  of  rau&cles  which 
are  considered  as  the  muscles  of  the  neck  proper ;  besides  those  of 
the  styloid  process.,  of  the  tongue,  of  the  pharynx,  of  the  palate,  and 
of  the  larynx,  which  constitute  five  more  groups  separate  and  distinct. 

OF   THE    COVERINGS. 

These  are  three  in  number.  First,  the  cutaneous  or  tegumentary 
covering,  which  is  thin,  abundantly  supplied  with  sebaceous  follicles, 
and  at  its  upper  part,  with  follicles  which  secrete  the  'haiir  or  beard  ; 
the  skin  here  is  loosely  attached  beneath,  it  is  extensible  and  retrac- 
tile, allowing  great  freedom  of  motion.  Second,  the  musculo-fascial 
covering,  composed  of  the  platysma  myoides  muscle,  and  the  fascia 
superficialis  ;  this  covering  is  composed  of  three  laminse,  the  platysma 
myoides  being  placed  between  two  laminae  of  the  superficial  fascia. 


28  DUBLIN    DISSECTOR, 

Third,  the  fascia  prof  undo,  cermc&lis,  which,  according  to  the  investi- 
gations of  Godman,  is  divided  into  six  processes,  forming  sheaths  for 
different  organs  on  the  neck  ;  and  one  of  which  descends  down  be- 
hind the  sternum,  into  the  thorax,  to  form  the  fibrous  lamina  of  the 
pericardium. 

OF  THE  SUB-REGIONS. 

The  anterior  cervical  region  is  divided  into  three  triangles  by  the 
sterno-cleido-mastoid  muscles.  One  of  these  is  between  the  two 
mastoid  muscles,  and  is  therefore  called  (he  inter -mastoid  ;  the  other 
two  are  above  the  clavicles  on  either  side  and  are  the  supra-clavicu- 
lar. The  inter-mastoid  triangle  is  bounded  on  either  side  by  the  an- 
terior edges  of  the  mastoid  muscles,  inferiorly  it  terminates  in  an 
apex,  at  the  sternum,  and  superiorly  its  base  is  formed  by  the  inferior 
maxilla,  the  tube  of  the  ear,  and  the  anterior  edge  of  the  mastoid 
process.  This  triangle  is  divided  into  two  spaces  by  the  os-hyoides, 
and  a  transverse  line  drawn  from  it,  to  the  edges  of  the  mastoid  mus- 
cles ;  the  space  above  is  the  supra-hyoideal  and  that  below  is  the 
infra-hyoideal ,-  in  the  former  we  find  the  tongue  and  epiglottis,  the 
upper  part  of  the  pharynx,  the  palate,  the  external  carotid  artery 
and  most  of  its  branches,  the  internal  jugular  vein,  the  sublingual, 
gustatory  and  other  nerves  :  the  sublingual,  sub-maxillary  and  parotid 
glands  besides  numerous  muscles ;  in  the  latter  are  situated  the 
larynx  and  the  trachea,  the  thyroid  body,  the  oesophagus  and  lower 
part  of  the  pharynx,  the  common  carotid  artery,  dnternal  jugular  vein, 
and  other  vessels,  the  pneumo-gastric  and  other  nerves.  In  the 
infra-hyoideal  region  there  are  two  points  at  which  the  common  cara- 
tid  artery  may  be  tied,  these  points  are  separated  by  the  orno-hyoid 
muscle ;  the  point  above  this  muscle  is  the  omo-mastoid  angle,  bounded 
externally  by  the  anterior  edge  of  the  mastoid  muscle,  and  internally 
by  the  superior  edge  of  the  omo-hyoid ;  in  this  angle  the  common 
carotid  artery  is  situated  internally,  the  internal  jugular  vein  exter- 
nally, and  the  pneumo-gastric  nerve  between  the  two  and  somewhat 
behind  them,  all  being  enclosed  in  a  common  sheath,  over  the  fore 
part  of  which  runs  the  descendens  noni  nerve  ;  these  organs  are  here 
superficial,  being  directly  beneath  the  coverings  of  the  neck;  the  space 
for  tying  the  artery  below  the  omo-hyoid  muscle,  is  the  omo-tracheal 
triangle,  which  is  bounded  superiorly,  by  the  lower  border  of  the  omo- 
hyoid,  externally  by  the  anterior  edge  of  the  sterno-mastoid,  and  in- 
ternally by  the  outer  edges  of  the  sterno-hyoid  and  sterno  thyroid 
muscles ;  in  this  space  we  find  the  same  organs  as  above  and  these 
holding  the  same  relation  to  each  other,  they  are  however  deeper 
seated,  because  in  addition  to  the  cervical  coverings,  they  are  over- 
lapped by  the  sterno-mastoid  and  sterno  thyroid  muscles. 

The  supra-clavicular  triangles  of  either  side  are  bounded  inferiorly 
by  the  clavicle,  posteriorly  or  externally,  by  the  anterior  edge  of  the 
trapezius,  and  anteriorly  by  the  external  edge  of  the  sterno-mastoid 
muscle.  These  triangles  are  each  divided  into  two  spaces  by  the 
inferior  belly  of  the  omo-hyoid  muscle  ;  the  space  above,  which  is 
very  much  the  largest,  is  the  omo-trapezian ;  that  below  is  the  omo- 
clavicular ;  in  the  former  we  find  the  cervical  plexus,  the  upper 
part  of  the  axillary  plexus,  arteries  and  veins,  and  in  this  space  we 


DUBLIN    DISSECTOR.  29 

sometimes  find  new  morbid  formations  or  enlarged  lymphatic  gan- 
glia ;  in  the  latter  are  situated,  frequently,  the  supra-scapular  artery, 
the  subclavian  artery  and  vein,  and  the  axillary  plexus  of  nerves,  also 
the  termination  of  the  external  jugular  vein ;  this  is  the  space  for 
tying  the  subclavian  artery  above  the  clavicle,  it  being  here  at  a 
depth  of  an  inch  and  a  half  to  two  inches,  from  the  surface  of  the 
neck  behind  the  clavicle ;  the  artery  is  bounded  inferiorly  and  some- 
what  anteriorly  by  the  vein,  and  superiorly  and  externally  by  the 
axillary  plexus  of  nerves. 

MUSCLES    OF   THE    NECK. 

As  already  stated,  there  are  four  groups  considered  as  the  muscles  of 
the  neck  proper,  these  groups  include  eighteen  pairs  of  muscles,  in 
the  first,  two  ;  in  the  second,  four ;  in  the  third,  five ;  and  in  the  fourth, 
seven :  besides  these  there  are  the  five  other  groups  referred  to,  in- 
eluding  twenty-one  pairs  of  muscles,  and  two  single  muscles,  viz. 
fifth,  the  styloid  muscles,  three  ;  sixth,  the  proper  muscular  structure 
of  the  tongue,  four ;  seventh,  the  muscles  of  the  pharynx,  three ; 
eighth,  the  muscles  of  the  palate  four  pairs  and  a  single  muscle ;  and 
ninth,  the  muscles  of  the  larynx,  seven  pairs  and  a  single  muscle ; 
so  that  upon  -the  anterior  region  of  the  neck  there  are  in  fact  thirty- 
nine  pairs  of  muscles  and  two  azygous  muscles. 

First  Group,  two  pairs  of  Muscles. 
Platysma  Myoides,  Vide  p.  32. 

Sterno  Cleido-Mastoideus,  "      "    34. 

This  group  extends  from  the  thorax  to  the  face  and  head,  the  first 
muscle  is  somewhat  analagous  to  the  sub-cutaneous  muscle  of  certain 
inferior  animals. 

Second  Group,  four  pairs  of  Muscles. 
Sterno-Hyoideus,  )  T,. ,        __ 

Sterno-Thyroideus,  }  Vlde  P-  36' 

Thyreo-Hyoideus,  "     «*   60. 

Omo-Hyoideus,  ««     «»  37. 

This  group  extends  from  the  thorax  to  the  os-hyoides,  and  is  for 
the  most  part  situated  in  the  infra-hyoideal  space,  the  muscles  are 
muscles  of  deglutition. 

Third  Group,  five  pairs  of  Muscles. 
Digastricus,  Vide  p.  39. 

Mylo-Hyoideus,  «    ««    41. 

Genio-Hyoideus,        j 
Hyo-Glossus, 
^enio-Hyo-Glossus,  $  Vlde  P'  42' 

This  group  extends  between  the  <os-hyoides,  lower  jaw,  and  tongue, 
•one  of  its  muscles  also  reaching  the  "base  of  the  cranium  ;  it  is  situa- 
ted in  the  -supra-hyoideal  space;  the  muscles  depress  (he  lower  jaw, 
elevate  the  os-hyoidee  and  move  the  tongue,  they  accordingly  act  in 
mastication,  in  articulation,  and  in  deglutition,  in  which  last  operation, 
they  are  antagonists  to  the  second  group,  the  -former  raising  the  os- 
hyoides  in  the  commencement  of  deglutition  and  the  latter  after- 


30  DUBLIN    DISSECTOR. 

wards  depressing  it.  These  three  groups  are  all  anterior  to  ihe 
larynx  trachea,  O3sophagus  and  pharynx,  while  the  next  and  fourth 
group  is  behind  those  organs,  lying  directly  upon  the  bodies  and 
transverse  processes,  of  the  cervical  vertebrae. 

Fourth  Group,  seven  pair  of  Muscles. 

Longus  Colii,  "| 

Rectus  Capitis  Anticus  Major,     I          yidg      g4 

Rectus  Capitis  Anticus  Minor,    J 

Rectus  Capitis  Lateralis,  J 

Scalenus  Anticus,  > 

Scalenus  Medius,    >    Vide  p.  65. 

Scalenus  Posticus,    j 

Fifth  Group,  three  pair  of  Muscles. 
Stylo-Hyoideus,         Vide  p.  43. 
Stylo-Glossus,  )  v, ,         ,. 

Stylo-Pharyngeus,    \  V( 

These  are  the  styloid  muscles  extending  from  the  styioid  process  of 
the  temporal  bone,  to  the  os  hyoides,  tongue,  and  pharynx,  they  are 
situated  in  the  supra-hyoideal  space,  and  are  muscles  of  deglutition, 
being  antagonists  of  the  second  group,  and  congeners  of  the  third. 

Sixth  group,  four  pair  of  Muscles. 

Lingualis,  Vide  p.  43. 

Superficial  Lingual  Muscle.    1 
Transverse  Lingual  Muscle,    >      Vide  p.  50. 
Vertical  Lingual  Muscle,         ) 

These  are  the  proper  muscles  of  the  tongue,  being  situated  entirely 
in  that  organ,  and  forming  a  large  part  of  its  substance.  They  are 
of  course  in  the  supra-hyoideal  region. 

Seventh  Group,  three  pair  of  Muscles. 

•Constrictor  Pharyngis  Inferior,  Vide  p.  51. 
•Constrictor  Pharyngis,  Medius,  )  v-j  ,.9 
•Constrictor  Pharyngis  Superior,  { 

These  muscles  are  situated  on  the  back  and  sides  of  the  pharynx, 
they  are  muscles  of  deglutition,  and  are  partly  above,  partly  below,  the 
level  of  the  es  hyoides. 

Eighth  Group,  four  pair ;  and  a  single  Muscle. 
Leva'tor  Palati,  •) 

Tensor  Palati,  or  Circumflexus, 

»•  r 


Palato-Glossus,  or  Constrictor  Isthmi  Faucium,    >  Vide  p.  55. 

Palato-Pharyngeus, 

Motor,  or  Azygos  Uvulee,  a  single  Muscle,  J 

These  muscles  are  situated  upon  the  soft  palate,  and  are  above  the 
os  hyoides,  they  act  upon  the  velum,  in  such  manner  as  to  cut  off  the 
openings  of  the  posterior  nares,  from  the  pharynx  in  deglutition,  so  as 
to  prevent  the  food  or  liquids  from  being  thrown  up  into  the  nares ; 
or  on  the  other  hand,  they  cut  off  the  mouth  from  the  pharynx,  so 


DUBLIN    DISSECTOR.  31 

that  fluids  or  gases,  may  be  thrown  up  into  the  nostrils,  and  pass  out 
through  the  anterior  nares. 

Ninth  Group,  seven  pairs ;  and  a  single  Muscle. 
Crico.Thyroideus,  Vide  p.  61. 

Crico-Arytenoideus  Posticus,  M  "•  62. 
Crico-Arytenoideus  Lateralis, ')  u  44  ... 
Thyreo-Arytenoideus,  ^ 

Arytenoideus  Obliquus,  "| 

Arytenoideus  Transversus,  a  single  Muscle,  I  Tr. , 
Aryteno-Epiglottideus,  '  Vlde  ?'  62' 

Thyreo-Epiglottideus, 

These  are  the  proper  muscles  of  the  larynx,  they  are  below  the  OH 
hyoides,  and  are  situated  parily  externally,  partly  internally,  in  refer- 
ence to  the  circumference  of  the  thyroid  cartilage  ;  they  act  upon  the 
cartilages  of  the  larynx  in  such  manner,  as  to  enlarge  or  diminish  the 
area  of  the  rima  glottidis,  and  relax  or  make  tense  the  chords  voca- 
les,  hence  the}'  are  the  muscles  of  the  voice.] 

DISSECTION    OF   THE    MUSCLES. 

RAISE  the  shoulders  of  the  subject  by  blocks  placed 
beneath  them,  so  as  to  make  tense  the  muscles  in  this  region ; 
divide  the  integuments,  which  in  this  region  are  thin  and 
delicate,  near  to,  and  in  a  line  with  the  clavicle,  also 
along  the  side  of  the  jaw  from  the  chin  to  the  mastoid 
process :  connect  these  incisions  by  another  made  in 
a  perpendicular  direction,  in  the  middle  line  from  the 
chin  to  the  sternum;  dissect  off  the  integuments  from 
before  backwards,  in  an  oblique  direction,  from  the  chin 
towards  the  clavicle;  this  should  be  done  cautiously, 
to  avoid  injuring  the  platysma  or  fascia  ;  in  the  child  and 
in  the  female  there  is  generally  more  subcutaneous  fat 
than  in  the  male  subject.  The  platysma  myoides  will  be 
now  fully  exposed,  and  the  sterno-mastoid  and  hyoid 
muscles  partially  so ;  in  the  middle  line  of  the  neck  a 
chain  of  projections  may  be  observed,  which  can  also  be 
felt  during  life,  viz.  a  little  below,  but  at  some  distance 
behind  the  chin,  is  the  body  of  the  os  hyoides ;  inferior  to 
this  is  the  angle  of  the  thyroid  cartilage  ;  next  is  the  cri- 
coid  below  which  the  commencement  of  the  trachea  may 
be  felt,  on  the  forepart  of  which  the  soft  swelling  of  the 
thyroid  body  can  be  discerned ;  and  lastly,  the  continua- 
tion of  the  trachea  descending  into  the  chest.  The  mus- 
cles on  the  anterior  part  of  the  neck  are  very  numerous, 
they  are  concerned  in  several  functions  and  execute  dif- 
ferent motions ;  some  act  as  the  ordinary  muscles  of  lo- 
comotion, others  are  -occasionally  engaged  in  deglutition, 
and  in  respiration,  also  in  the  exercise  of  voice  and  speech. 
They  are  symmetrical,  or  similar  on  each  side  of  the  mid- 
dle line  ;  they  are  twenty-one  pair  in  number,  and  may  be 
arranged  for  the  convenience  of  dissection  into  three  layers, 


02  DUBLIN    DISSECTOR. 

a  superficial,  middle,  and  deep ;  the  superficial  consists  of 
two  pair,  the  platysma  myoides  and  sterno-cleido  mastoid  ; 
the  middle  may  be  divided  into  two  orders,  the  inferior  and 
superior ;  the  inferior  are  three  in  number,  viz.  sterno-hyoid, 
thyreo-hyoid,and  omo-hyoid ;  the  superior  are  nine  in  num- 
ber, viz.  digastric,  mylo-hyoid,  genio-hyoid ;  three  styloid 
muscles,  hyo-glossus,  genio-hyo-glossus,  and  lingualis  mus- 
cles ;  the  deep  layer  consists  of  seven  pair,  viz.  longus  colli, 
rectus  capitis  anticus,  major  and  minor,  rectus  lateralis, 
and  three  scaleni ;  this  arrangement  excludes  the  muscles 
of  the  palate,  pharnx,  and  larynx. 

I^LATVSJVTJUMYOIDES,  or  latissimus  colli,  is  a  .thin  and  pale 
cutaneous  muscle,  in  many  subjects  weak,  and  even  indis- 
tinct, is  situated  on  the  forepart  and  side  of  the  neck,  ex- 
tending from  the  thorax  to  the  face  ;  its  figure  is  somewhat 
square,  being  a  little  longer  than  it  is  broad,  and  narrower 
in  the  centre  than  at  either  end;  it  arises  by  many  fine 
fleshy  fibres  from  the  cellular  membrane,  covering  the  up- 
per part  of  the  deltoid  and  pectoral  muscles,  a  few  also 
adhere  to  the  clavicle ;  the  fibres  ascend  obliquely  inwards, 
at  first  loosely,  afterwards  closely  connected  to  each  other, 
and  form  a  broad  thin  muscle,  covering  the  side  of  the 
neck,  inserted,  first,  into  the  skin  and  cellular  tissue  on  the 
chin,  decussating  there  with  fibres  from  the  opposite  side ; 
second,  into  the  fascia  along  the  side  of  the  lower  jaw,  a 
few  only  into  the  bone  ;  some  fibres  may  be  traced  high 
on  the  face,  and  seen  to  join  the  depressor  anguli  oris,  the 
zygomatic  and  orbicularis  palpebrarum  muscles;  and 
third,  into  the  fascia,  which  covers  the  parotid,  and  which 
adheres  to  the  meatus  auditorius.  Use,  to  depress  the  angle 
of  the  lips  and  the  lower  jaw,  but  if  the  mouth  be  closed 
it  may  elevate  the  integuments  of  the  neck ;  it  also  serves 
to  compress  and  support  the  several  muscles,  glands,  and 
vessels  in  this  region.  The  platysma  is  covered  only  by 
the  skin  [and  anterior  lamina  of  the  superficial  fascia;]  it 
partly 'conceals  the  clavicle  and  the  deltoid  and  pectoral 
muscles, the  sterno-mastoid,  hyoid,  and  thyroid  muscles; 
also  the  digastric  and  stylo-hyoid,  the  sub-maxillary  gland, 
the  lower  part  of  the  parotid,  the  side  of  the  jaw  and  some 
of  the  muscles  of  the  face ;  also,  in  part,  the  external,  ju- 
gular vein :  this  vein  commences  in  the  parotid  gland,  de- 
scends obliquely  outwards  over  the  sterno-mastoid  muscle, 
where  it  lies  very  superficial  and  then  sinks  behind  the 
clavicle,  and  joins  the  subdavian  vein  or  some  of  its 
branches.  The  upper  portion  of  the  external  jugular  vein 
is  accompanied  by  a  large  nerve,  which  lies  to  its  outer 
side,  superficialis  colli,  a  branch  of  the  cervical  plexus  as- 
cending to  the  parotid  gland  and  external  ear.  This  vein 


DUBLIN    DISSECTOR.  33 

in  its  course  down  the  neck  receives  several  cutaneous 
veins,  and  frequently  communicates  with  the  internal  ju- 
gular :  it  presents  great  varieties  in  its  size  and  course,  and 
is  sometimes  even  wanting.  Superficial  veins  may  also  in 
general  be  marked  descending  along  the  anterior  part  of 
the  neck  ;  they  arise  about  the  os  hyoides  and  upper  part 
of  the  thyroid  body,  and  descend  beneath  some  fibres  of 
the  platysma  along  the  anterior  edge  of  the  mastoid  mus- 
cle, and  end  in  the  internal  or  external  jugular,  or  in  the 
vena?  innominate. 

[Variety.  This  muscle  is  sometimes  though  rarely  found  thick 
and  round,  and  inserted  into  the  occiput  instead  of  being  distributed 
upon  the  face.] 

The  fibres  of  the  platysma  are  closely  connected  to 
a  layer  of  condensed  cellular  tissue,  which  in  some  sub- 
jects* is  very  strong,  and  in  some  situations  aponeurotic ; 
this  is  the  superficial  cervical  fascia ,*  this  fascia  extends 
over  the  anterior  and  lateral  parts  of  the  neck ;  is  con- 
tinued down  over  the  forepart  of  the  thorax,  where  it 
becomes  cellular  and  adipose ;  ascends  to  the  jaw,  to 
which  it  is  attached;  expands  over  the  parotid  gland  and 
adheres  to  the  cartilage  of  the  ear ;  dn  this  situation  its 
strength  is  greatly  increased :  towards  the  lateral  and  pos- 
terior parts  of  the  neck  it  becomes  weak  like  cellular  mem- 
brane. From  the  posterior  or  deep  surface  of  this  fascia 
a  lamina  of  membrane  is  derived,  which  passes  behind  the 
sterno-mastoid  muscle  :  this  is  the  deep  cervical  fascia,  whose 
connexions  are  important,  and  may  be  examined  in  this 
stage  of  the  dissection.  If  the  superficial  lamina  bo  di- 
vided along  the  median  line  of  the  sterno-mastoid  muscle, 
this  deep  fascia  will  be  seen  to  be  continuous  with  or  pro- 
duced from  the  superficial,  and  to  pass  behind  the  anterior 
border  to  the  posterior  surface  of  that  muscle,  so  that  the 
latter  may  be  considered  -as  enclosed  between  these  fasciae : 
at  the  lower  part  of  the  neck  it  is  strong,  and  adheres  to 
the  inter-clavicular  ligament  and  posterior  edge  of  the 
sternum  and  clavicles.  Some  loose  fatty  substance  is  here 
interposed  between  it  and  the  superficial  fascia:  as  the 
deep  fascia  extends  upwards,  it  covers  and  adheres  to  the 
sheath  of  the  cervical  vessels,  and  arriving  at  the  space 
between  the  trapezius  and  mastoid  muscles,  it  becomes 
weak  and  cellular,  inferiority  accompanying  the  great  ves- 
sels beneath  the  clavicle,  and  superiorly  lost  on  the  branches 
of  the  cervical  plexus  of  nerves  ;  at  the  superior  and  lat- 
eral parts  of  the  neck  it  sinks  deep,  behind  the  angle  of 
the  jaw,  to  which  it  adheres,  and  is  connected  to  the  styloid 
process  of  the  temporal  bone,  and  to  the  stylo-maxillary 
ligament ;  absorbent  ganglia,  the  lower  part  of  the  parot- 


34  DUBLIN    DISSECTOR. 

id,  and  much  cellular  membrane  here  lie  between  these 
two  fascse.  In  this  situation  collections  of  matter  often 
form,  the  result  of  cynanche  parotidyea,  or  of  inflammation 
of  some  of  the  lymphatic  ganglia:  such  collections  are 
productive  of  great  inconvenience,  causing  such  swelling 
and  tension  as  to  interfere  with  the  motions  of  the  jaw,  and 
with  the  act  of  deglutition.  The  cervical  fasciae  bind  down 
the  muscles  and  support  the  vessels  and  glands  in  this  re- 
gion ;  at  the  lower  part  of  the  neck  they  serve  to  protect 
the  trachea  and  the  upper  part  of  the  thorax  from  the 
pressure  of  the  atmosphere  during  inspiration.  Dissect 
off  the  platysma  and  superficial  fascia,  and  examine  the 
subjacent  muscles,  the  second  pair  of  the  first  order, 

^yERNo-CLEiDo  MASToiDEus,  long  and  flat,  placed  at  the 
anterior  and  lateral  part  of  the  neck,  arises  by  a  strong  flat 
tendon  with  fleshy  fibres  posterior  to  it,  from  the  upper 
and  anterior  part  of  the  first  bone  of  the  sternum,  also  by 
short  aponeurotic  and  fleshy  fibres  from  the  upper  and  an- 
terior edge  of  the  sternal  third,  sometimes  half  of  the 
clavicle ;  a  small  triangular  space  separates  these  two  or- 
igins, through  which  small  vessels  and  some  cellular  mem- 
brane pass :  this  space  corresponds  to  the  sterno-clavicu- 
lar  articulation. 

The  sternal  and  longer  portion  of  this  muscle  ascends 
obliquely  backwards  and  outwards,  and  overlaps  the  clav- 
icular, which  ascends  vertically;  about  the  middle  of  the 
neck  they  are  intimately  joined,  and  are  inserted  by  a  thin, 
broad  aponeurosis  into  the  upper  part  of  the  mastoid  pro- 
cess, and  into  the  external  third  of  the  superior  transverse 
ridge  of  the  occipital  bone.  Use,  the  sternal  portion  can 
rotate  the  head  so  as  to  turn  the  face  towards  the  opposite 
side  :  the  clavicular  can  bend  the  head  and  neck  to  its  own 
side,  so  as  to  approximate  the  ear  and  shoulder ;  and  if 
the  two  portions  of  the  muscle  on  each  side  act  together, 
they  will  move  the  head  downwards  and  forwards,  but  if 
the  muscles  on  the  back  of  the  neck  be  in  action,  so  as  to 
fix  the  vertebrae  and  head,  then  these  muscles,  particularly 
the  sternal  portions,  may  assist  in  still  further  extending 
the  neck,  and  carrying  the  head  backwards,  in  consequence 
of  their  insertion  being  posterior  to  the  centre  of  motion 
in  the  occipital  condyles;  this  appears  to  be  the  case  in 
tetanus :  these  muscles  can  also  assist  in  laborious  respi- 
ration, by  raising  and  fixing  the  shoulders.  This  muscle 
is  covered  by  the  integuments,  platysma,  superficial  fascia, 
external  jugular  vein,  ascending  branches  of  the  cervical 
plexus  of  nerves,  and  by  a  small  portion  of  the  parotid 
gland ;  it  conceals  part  of  the  sternum  and  clavicle,  of  the 
sterno-hyoid,  sterno  thyroid,  omo-hyoid,  and  digastric  mus- 


DUBLIN    DISSECTOR.  35 

cles,  also  the  lower  part  of  the  cervical  vessels  and  several 
ganglia.  The  spinal  accessory  nerve  perforates  this  mus- 
cle a  little  above  its  centre,  and  near  its  posterior  surface ; 
this  nerve  is  a  division  of  the  eighth  pair,  it  distributes 
small  branches  to  the  mastoid  and  trapezius  muscles,  and 
joins  freely  with  the  cervical  plexus ;  the  spinal  accessory 
does  not  always  perforate,  but  sometimes  passes  posterior 
to  the  mastoid  muscle. 

[Varieties.  The  fissure  between  the  sternal,  and  clavicular  origins 
is  sometimes  wanting,  the  two  origins  being  continuous ;  sometimes 
there  is  an  isolated  fasiculus  at  its  posterior  margin ;  sometimes  its 
inferior  extremity  descends  as  low  as  to  the  rectus  abdominis  or  even 
to  the  end  of  the  sternum.] 

The  student  may  remark  that  the  two  sterno-mastoid 
muscles  bound  a  large  triangular  space  situated  on  the  fore- 
part of  the  neck,  the  apex  at  the  sternum,  the  base  at  the 
jaw :  this  is  divided  by  the  mesial  line  into  two  lateral  por- 
tions, which  are  named  the  anterior  lateral  triangles  of  the 
neck. 

Between  the  mastoid  and  the  trapezius  muscle  also,  on 
each  side,  a  large  triangular  space  is  enclosed,  the  base  form- 
ed by  the  clavicle,  the  apex  by  the  mastoid  process ;  this 
space  is  called  the  posterior  lateral  triangle  of  the  neck. 
Both  these  triangular  regions  may  be  observed  to  be  sub- 
divided into  two  by  the  omo-hyoid  muscle,  which  crosses 
the  neck  obliquely  from  the  shoulder  to  the  os-hyoides. 
Thus  on  each  side  of  the  middle  line  four  triangle  spaces 
may  be  noticed,  principally  formed  by  the  trapezius,  ster- 
no-mastoid, and  omo-hyoid  muscles ;  these  triangles  are 
distinguished  by  the  terms — 1.  posterior  inferior ;  2.  pos- 
terior superior ;  3.  anterior  inferior  ;  and  4.  anterior  supe- 
rior. 

The  student  should  examine  each  of  these  regions,  and 
consider  the  parts  situated  in  them.  These  spaces  can  be 
ascertained  during  life,  and  therefore  an  accurate  know- 
ledge of  the  contents  of  each  may  be  of  practical  impor- 
tance. 1.  The  posterior  inferior  triangle  is  that  small  space 
behind  the  clavicular  portion  of  the  mastoid  muscle,  be- 
tween the  clavicle  and  posterior  belly  of  the  omo-hyoid 
muscle ;  in  this  space  we  find  the  subclavian  artery,  vein, 
and  brachial  plexus  of  nerves ;  it  is  here  that  the  operation 
of  tying  the  subclavian  artery,  in  case  of  axillary  aneu- 
rism, is  recommended  to  be  performed.  2.  The  posterior  su- 
perior triangle  is  above  the  posterior  belly  of  the  omo-hy- 
oid, and  between  the  mastoid  and  trapezius  muscles ;  it 
contains  the  cervical  plexus  of  nerves,  several  lymphatic 
ganglia,  and  a  great  quantity  of  cellular  membrane.  3. 
The  anterior  inferior  triangle  is  above  the  sternal  third  of  the 


36  DUBLIN    DISSECTOR. 

clavicle  between  the  median  line  and  anterior  belly  of  the 
omo-hyoid ;  this  space  contains  the  carotid  artery,  jugular 
vein,  and  accompanying  nerves,  also  the  lateral  lobe  of  the 
thyroid  body,  all  of  which  are  covered  by  the  sterno-mas- 
toid,  hyoid,  and  thyroid  muscles.  4.  The  anterior  superior 
triangle  is  between  the  sterno-mastoid  and  anterior  belly  of 
the  omo-hyoid  muscles ;  the  apex  is  formed  by  the  decus- 
sation  of  these  muscles,  and  is  opposite  the  cricoid  cartil- 
age ;  the  base  is,  superiorly,  marked  by  the  digastric  mus- 
cle and  lingual  nerve ; — this  space  also  contains  the  great 
vessels  and  nerves,  which  here,  however,  are  only  super- 
ficially covered,  so  that  in  this  situation  the  operation  of 
tying  the  carotid  artery  can  be  more  easily  effected.  Di- 
vide the  sterno-mastoid  muscle  about  its  centre,  and  reflect 
each  portion  towards  its  attachment ;  at  the  lower  part  of 
the  neck,  behind  and  between  the  sterno-mastoid  muscles, 
are  seen  the  following : 

STERNO-HYOIDEUS  is  long,  flat,  and  thin,  arises  within  the 
thorax  from  the  posterior  surface  of  the  first  bone  of  the 
sternum,  cartilage  of  the  first  rib,  sternal  end  of  the  clav- 
icle, and  sterno-ciavicular  capsule ;  ascends  obliquely  in- 
wards, approximating  its  fellow  above,  and  is  inserted  into 
the  lower  border  of  the  body  of  the  os  hyoides,  internal  to 
the  omo-hyoid,  [with  which  it  is  here  closely  connected  for 
a  short  distance.]  Use,  to  depress  the  os  hyoides,  pharynx 
and  larynx.  This  muscle  is  covered  by  the  sternum  and 
clavicle,  by  the  sterno-mastoid  and  integuments ;  it  lies  on 
the  sterno  thyroid,  crico-thyroid,  and  thyreo-hyoid  muscles, 
and  on  the  thyroid  body  and  its  vessels ;  a  tendinous  line 
often  intersects  it  about  its  centre. 

[Varieties.  This  muscle  sometimes  is  double,  sometimes  it  arises 
from  the  middle  of  the  clavicle,  and  at  other  times  in  common  with 
the  next  muscle.] 

Cut  this  muscle  across,  and  reflect  each  portion  towards 
its  attachments,  and  we  see  the  following  pair  of  muscles : 

STERNO-THYROIDEUS  is  broader  and  shorter  than  the  last, 
arises  from  the  posterior  surface  of  the  sternum  and  cartil- 
age of  the  second  rib,  ascends  obliquely  outwards,  [diver- 
ging from  its  fellow,]  and  is  inserted  into  the  oblique  line 
on  the  ala  of  the  thyroid  cartilage.  Use,  to  depress  the 
larynx.  This  muscle  is  covered  by  the  sterno-mastoid  and 
hyoid  muscles,  and  by  the  skin  ;  it  conceals  the  arteria  and 
vena  innominata,  the  carotid  and  subclavian  vessels,  and 
adjacent  nerves,  also  the  thyroid  body,  and  the  trachea ; 
between  it  and  the  latter  there  is  a  considerable  quantity 
of  cellular  membrane,  which  contains  several  veins  (infe- 
rior thyroid  v.)  Several  filaments  of  the  descendens  noni 
nerve  are  distributed  to  this  and  to  the  former  muscle.  It 


DUBLIN    DISSECTOR.  37 

is  between  the  sterno-thyroid  muscles  that  the  operation  of 
tracheotomy  is  performed,  while  that  of  laryngotomy  is 
between  the  sterno-hyoid  muscles,  and  between  the  thyroid 
and  cricoid  cartilages* 

[Varieties.  This  muscle  is  sometimes  double,  sometimes  lost  upon 
adjoining  muscles,  and  sometimes  connected  to  its  fellow  by  trans 
verse  fibres.] 

OMO-HYOIDEUS  is  long,  slender,  and  digastric,  situated  ob- 
liquely along  the  side  and  forepart  of  the  neck,  it  arises 
broad  and  fleshy  from  the  superior  costa  of  the  scapula 
behind  its  semilunar  notch,  from  the  ligament  covering 
that  notch,  sometimes  from  the  base  of  the  coracoid  pro- 
cess, and  sometimes  also  from  the  acromial  end  of  the  cla- 
vicle ;  it  ascends  obliquely  forwards  a  little  above  the  cla- 
vicle, passes  beneath  the  sterno-mastoid  muscle,  where  it 
is  generally  tendinous,  except  in  the  very  young  subject ; 
becoming  again  fleshy,  it  ascends  nearly  vertical  along  the 
outer  side  of  the  sterno-hyoid,  and  is  inserted  fleshy  into 
the  lower  border  of  the  os  hyoides,  at  the  junction  of  its 
body  and  cornu.  Use,  the  muscle  of  one  side  cannot  act 
independent  of  the  other,  both  draw  the  os  hyoides,  phar- 
ynx, and  larynx,  downwards  and  backwards,  and  in  deg- 
lutition serve  to  urge  the  food  into  the  oesophagus.  The 
origin  of  this  muscle  is  concealed  by  the  trapezius,  it  is 
anterior  to  the  insertion  of  the  levator  anguli  scapulae,  and 
between  the  serratus  magnus  and  supra-spinatus  muscles ; 
the  posterior  belly  is  covered  by  the  integuments  and  fas- 
cia, in  some  the  clavicle  overhangs  it ;  it  divides  the  great 
posterior  lateral  triangle  of  the  neck  into  an  inferior  and 
superior  part,  as  was  before  mentioned  ;  this  portion  of  the 
omo-hyoid  can  frequently  be  distinguished  in  the  living 
neck.  The  tendon  crosses  the  carotid  artery  and  jugular 
vein,  and  is  covered  by  the  sterno-mastoid,  which  can  thus 
move  more  easily  on  this  structure.  The  anterior  belly 
and  insertion  are  covered  by  the  integuments  and  fascia ; 
this  portion  of  the  muscle  divides  the  anterior  lateral  tri- 
angle of  the  neck  into  an  inferior  and  superior  part.  The 
omo-hyoid  crosses  over  the  scaleni  muscles,  the  brachial 
plexus,  phrenic,  pneumogastric  and  sympathetic  nerves,  the 
carotid  artery,  jugular  vein,  and  superior  thyroid  vessels. 

[Varieties.  This  muscle  is  sometimes  double,  and  has  one  in- 
sertion into  the  side  of  the  tongue.  We  have  been  informed  of  one 
subject,  in  which  the  muscle  was  entirely  wanting  on  one  side.] 

Beneath  the  three  last  described  muscles,  and  lying  on 
the  trachea  and  sides  of  the  larynx,  is  a  large,  soft,  red 
mass,  of  a  crescentic  shape,  the  concavity  directed  up- 
wards ;  this  is  the  thyroid  body ;  it  is  in  general  larger  and 
of  a  deeper  colour  in  the  child  than  in  the  adult  or  old 


38  DUBLIN    DISSECTOR, 

[subject]  and  in  the  female  than  in  the  male  ;  its  sizer how- 
ever, varies  considerably  in  different  individuals,  even  of 
the  same  sex  and  age. 

[Still  its  average  weight  may  be  set  down  as  about  one  ounce  in  a 
state  of  health,  in  a  diseased  state  it  sometimes  weighs  as  much  as  a 
pou?id  and  a  half ;  its  transverse  measurement  is  three  inches  and  a 
quarter ;  its  vertical  measurement  a  little  over  two  inches.] 

It  consists  of  two  large  pyramidal  portions,  called 
lateral  lobes^  connected  together  by  a  narrow  slip,  the  mid- 
dle lobv  or  isthmus  ;  the  latter  is  thin  and  flat,  and  closely 
connected  to  the  second,  third,  and  fourth  rings  of  the 
trachea ;  the  lateral  lobes  are  plump  and  convex,  large 
below,  pointed  above,  placed  by  the  side  of  the  trachea 
and  larynx,  and  extending  as  high  as  the  ala3  of  the  thy- 
roid cartilage  ;  the  left  lateral  lobe  rests  on  the  oesophagus, 
and  both  right  and  left  overlap  the  carotid  artery,  inferior 
thyroid  vessels,  and  recurrent  nerve ;  they  are  covered  by 
the  sterno-mastoid,  hyoid,  thyroid,  and  omo-hyoid  muscles, 
by  the  platysma  and  skin  ;  they  lie  on  the  side  of  the 
trachea  and  larynx,  on  the  crico-thyroid  and  inferior  con- 
strictor of  the  pharynx.  The  middle  lobe  is  very  irregu- 
lar, it  is  sometimes  deficient;  in  some  cases  it  passes 
behind  the  oesophagus,  or  between  this  tube  and  the  trachea 
a  circumstance  which  might  be  productive  of  great  incon- 
venience,, and  even  danger,  in  the  event  of  enlargement  of 
this  body  occurring  in  one  in  whom  this  malformation  exist- 
ed. A  narrow  slip  is  often  seen  to  ascend  from  the  mid- 
dle lobe  as  high  as  the  os  hyoides,  [being  generally  placed  a 
little  to  the  left  of  the  median  line  ;  following  very  nearly 
the  course  of  this  process,  and  frequently  confounded  with 
with  it,  is  sometimes  found  a  small  muscle  the  levator  glan- 
dula  thyroide<c.,  it  is  attached  below  to  the  isthmus  of  the 
thyroid  body,  and  above  to  the  lower  margin  of  the  base  of 
the  os  hyoides.]  In  the  infant  the  lower  part  of  the  thyroid  is 
connected  to  the  thymus  body.  This  organ  has  no  perfect 
capsule,  a  fine  cellular  tissue  only  surrounds  it ;  it  is  of  a 
soft  and  spongy  texture,  the  cells  contain  a  yellow,  serous, 
and  sometimes  an  oily  fluid,  it  appears  composed  of  a 
number  of  granulations  united  by  cellular  tissue  into  lo- 
bules, the  serous  fluid  is  contained  in  the  connecting  cel- 
lular membrane,  no  excretory  duct  has  been  discovered, 
nor  does  there  appear  to  be  any  communication  between 
the  lobes  and  lobules,  except  through  the  medium  of 
the  blood-vessels,  which  are  of  considerable  size ;  four 
arteries,  two  from  the  carotid  and  two  from  the  subcla- 
vian,  are  distributed  to  it,  the  former  border  its  superior 
margin,  the  latter  bend  along  its  inferior  and  pos- 
terior portions ;  several  veins  issue  from  it,  small  superior- 


DUBLIN    DISSECTOR.  39 

ly,  but  very  large  and  numerous  below.  This  body  has 
been  by  many  considered  as  glandular,  and  named  ac- 
cordingly the  thyroid  gland,  but  there  does  not  appear 
any  evidence  to  support  this  opinion  ;  it  cannot  belong  to 
the  secreting  glands  unless  we  admit  that  its  veins  (which 
are  certainly  very  large)  serve  the  additional  office  of  ex- 
cretory ducts,  neither  does  it  appear  to  have  any  peculiar 
connection  with  the  lymphatic  or  absorbent  system. 
Anatomical  writers  usually  describe  it  in  •connexion  with 
the  larynx,  but  without  any  reason  except  from  its  conti- 
guity to  that  organ.  Although  it  is  an  opinion  prevalent 
among  .-many  physiologists  that  the  thyroid  body  is  ,an 
organ  for  sanguification,  yet  it  may  be  affirmed  that  its  use 
is  by  no  means  fully  ascertained. 

The  fthyroid  body  is  very  subject  to  enlargement,  which 
is  sometimes  partial,  sometimes  general,  this  affection  is 
named  bronchocele  or  goitre,  and  presents  great  varieties  as 
to  size,  form,  and  consistence  of  the  tumor,  in  some  being 
firm  and  regular,  in  others  very  uneven,  and  soft  or  pulpy 
to  the  feel. 

[Suppuration  is  sometimes  the  result  of  acute,  but  more  often  of 
chronic  inflammation  of  the  organ,  and  in  some  cases  the  accumula- 
tion of  pus,  is  very  great ;  five  pounds  of  purulent  matter  having 
been  found  in  one  of  these  abcesses,  which  was  eventually  cured. 
This  organ  is  also  the  seat  of  calcareous  concretions,  of  cartilaginous 
and  osseous  formations,  and  of  schirrus.  One  form  of  enlargement 
seems  to  depend  upon  a  varicose  condition  of  the  vessels,  and  Dr. 
Mott,  mentions  that  in  a  case  upon  which  he  operated,  he  found  the 
thyroid  arteries  in  their  trunks,  .nearly  as  large  as  the  end  of  his  little 
finger.  Enlargement  of  this  body  occurs  in  many  of  the  inferior 
animals.] 

Next  dissect  the  muscles  at  the  upper  part  of  the  neck. 

DIGASTRICUS,  placed  at  the  lateral  and  anterior  part  of 
the  neck,  thick  and  fleshy  at  each  extremity,  round  and 
tendinous  in  the  centre,  arises  from  a  groove  in  the  tem- 
poral bone,  internal  to  the  mastoid  process,  descends  ob- 
liquely forwards  and  inwards,  ends  in  a  round  tendon 
which  perforates  the  stylo-hyoid  muscle,  and  is  connected 
to  the  cornu  of  the  os  hyoides  by  a-dense  fascia,  sometimes 
by  a  tendinous  ring  like  a  pully  ;  the  tendon  is  then  re- 
flected upwards  and  forwards,  and  soon  ends  in  the  ante- 
rior fleshy  belly,  which  continuing  forwards  and  inwards, 
is  inserted  into  a  rough  depression  on  the  inner  side  of  the 
base  of  the  jaw,  close  to  the  symphysis.  Use,  to  depress  the 
lower  jaw,  and  when  the  mouth  is  closed,  to  elevate  the  os 
hyoides,  tongue  and  larynx ;  the  posterior  belly  can  also 
draw  these  backwards  and  upwards,  and  the  anterior  up- 
wards .and  forwards,  so  that  this  muscle  can  exert  great 


40  DUBLIN*    DISSECTOR. 

influence  in  deglutition ;  it  can  also  draw  the  head  back- 
wards, if  the  chin  be  fixed, 

[Variety.  This  muscle  is  often  adherent  by  its  anterior  belly  to 
its  fellow  of  the  opposite  side.] 

The  digastric  is  covered  posteriorly  by  the  sterno-mas- 
toid  and  splenius,  and  by  a  portion  of  the  parotid,  more 
anteriorly  by  a  few  fibres  of  the  stylo-hyoideus  and  a 
small  part  of  the  submaxillary  gland,  by  the  cervical 
fascia,  platysma  and  skin ;  it  passes  across  the  styloid 
muscles,  the  external  and  internal  carotid,  the  labial  and 
lingual  arteries,  the  eighth,  ninth,  and  sympathetic  nerves ; 
also  the  origin  of  the  hyo-glossus  and  insertion  of  the 
mylo-hyoid.  In  the  .position  in  which  the  subject  is 
placed  during  this  dissection,  the  muscle  forms  the  inferior 
or  convex  border  of  a  semicircular  space,  the  superior 
strait  edge  of  which  is  marked  by  the  side  of  the  maxilla, 
and  by  a  line  continued  from  its  angle  to  the  mastoid 
process :  this  digastric  space  is  divided  by  the  stylo-maxil- 
lary ligament  into  a  posterior  and  anterior  part.  The 
posterior  smaller  one  contains  the  parotid  gland,  the  caro- 
tid artery,  and  seventh  pair  of  nerves  ;  and  deeper  than  these, 
the  styloid  process  and  origin  of  the  styloid  muscles,  also 
the  internal  carotid  artery,  jugular  vein,  and  eighth,  ninth, 
and  sympathetic  nerves.  The  anterior  digastric  space 
contains  the  submaxillary  gland,  the  facial  and  lingual 
arteries;  the  lingual  and  gustatory  nerves,  the  several 
small  muscles,  which  connect  the  tongue  and  os  hyoides 
to  the  chin,  also  the  sublingual  gland,  which  cannot  be 
seen  in  the  present  stage  of  dissection.  The  student 
should  examine  the  connexions  of  the  submaxillary  gland 
before  he  dissects  the  muscles  in  this  region. 

The  submaxillary  is  the  second  of  the  salivary  glands, 
of  an  oval  form  and  pale  colour,  surrounded  by  cellular 
membrane  and  several  absorbent  ganglia  covered  by  the 
skin,  platysma  and  fascia,  bounded  posteriorly  by  the 
digastric  tendon,  externally  by  the  internal  pterygoid 
muscle  and  stylo-maxillary  ligament;  anteriorly  by  the 
side  of  the  maxilla,  and  internally  by  the  anterior  belly 
of  the  digastric ;  it  rests  on  the  mylo-hyoid,  stylo-hyoid 
and  hyo-glossus  muscles ;  a  small  process  of  the  gland 
accompanies  its  excretory  duct,  turns  round  the  posterior 
edge  of  the  mylo-hyoid,  and  lies  between  the  upper  sur- 
face of  that  muscle  and  the  membrane  of  the  mouth  ;  this 
process  frequently  joins  the  sublingual  gland.  The  facial 
artery  and  vein  pass  through  a  deep  groove  in  this  gland, 
[passing  between  the  gland  and  base  of  the  inferior  maxilla.] 
The  duct  of  this  gland  is  called  Whartonian  duct, -it  arises  by 


DUBLIN    DISSECTOR.  41 

numerous  fine  radicles  from  the  lobules  of  the  gland, 
leaves  it  at  its  outer  end,  winds  above  the  mylo-hyoid 
muscle,  and  runs  forwards  and  inwards  towards  the  frae- 
num  linguae,  by  the  side  of  which  it  opens  into  the  mouth ; 
the  orifice  can  be  distinctly  seen  in  the  mouth,  in  a  promi- 
nent papilla,  which  appears  when  the  anterior  part  of  the 
tongue  is  raised  :  this  duct  is  about  two  inches  and  a  halt 
long,  is  thin  and  transparent,  its  coats  are  weaker,  but  its 
calibre  is  larger  than  in  Steno's  duct,  the  gustatory  nerve 
accompanies  it,  at  first  superior  but  afterwards  inferior 
to  it :  sometimes  a  second  or  accessory  duct  is  met  with. 

The  submaxillary  gland  is  subject  to  the  same  morbid 
changes  as  those  which  have  been  alluded  to  in  speaking 
of  the  parotid  gland.  Its  removal  in  case  of  scirrhus  is 
also  spoken  of  by  authors,  and  this  operation  has  been 
described  as  having  been  frequently  performed ;  most 
probably,  however,  many  of  these  recorded  accounts  were 
rather  cases  of  tumors  which  have  pressed  this  gland  aside, 
and  have  thus  come  to  occupy  its  place.  The  Whartoni- 
an  duct  is  not  unfrequently  obstructed  near  to,  or  closed 
at  its  termination  in  the  mouth,  the  saliva  then  distends  it 
into  the  form  of  a  tumour  of  variable  size,  which  is  situa- 
ted beneath  the  tongue,  and  causes  more  or  less  inconve- 
nience to  the  latter ;  this  disease  is  termed  Ranula.  De- 
tach this  gland  from  the  mylo-hyoid,  turn  it  outwards, 
leaving  the  duct  and  deep  process  to  be  further  examined 
afterwards ;  separate  the  anterior  belly  of  the  digastric 
from  the  chin,  and  we  see  the  following  muscle. 

MYLO-HYOIDETJS,  triangular,  arises  from  the  oblique  line 
(the  myloid  ridge,)  on  the  inner  surface  of  the  side  of  the 
maxilla,  which  line  descends  obliquely  from  beneath  the 
last  molar  tooth  towards  the  chin  ;  the  fibres  descend  obli- 
quely inwards  and  backwards  to  the  mesial  line,  and  are 
inserted  into  the  base  of  the  os  hyoides,  and  along  with  its  fel- 
low, into  a  middle  tendinous  line  between  that  bone  and  the 
chin. 

[This  muscle  forms  the  floor  of  the  mouth.] 

Use,  to  elevate  the  os  hyoides  and  tongue,  so  as  to  press 
the  latter  against  the  palate.  This  muscle  is  .covered  by 
the  submaxillary  gland,  and  by  the  digastric.;  it  lies  on 
the  hyo-glossus,  stylo-glossus,  -and  genio-hyoid  muscles, 
and  conceals  the  Whartonian  duct,  the  lingual  and  gusta- 
tory nerves  and  sublingual  gland. 

[Variety.  This  muscle  is  sometimes  lost  in  part  ijpon  the  middle 
tendon  of  the  digastric,  or  upon  the  sterno-hyoideus.] 

Detach  this  muscle  from  the  os  hyoides  and  from  its  fel- 
low ;  in  the  middle  line  we  shall  then  see  the  following  pair. 


42  DUBLIN    DISSECTOR. 

GENIO-HYOIDEUS,  short  and  round,  arises  by  a  small  ten- 
don  on  the  inner  side  of  the  chin,  above  the  digastric,  des- 
cends obliquely  backwards,  and  is  inserted  broad  and  fleshy 
into  the  base  of  the  os  hyoides.  Use,  to  draw  the  os 
hyoides  upwards  and  forwards,  to  push  the  tongue  against 
the  incisor  teeth,  or  protrude  it  from  the  mouth  :  this  pair 
of  muscles  lie  superior  to  the  digastric  and  mylo-hyoid, 
and  inferior  to  the  genio-hyo-glossus. 

[Varieties.  This  muscle  is  sometimes  double  on  both  sides,  some- 
times there  is  but  one  muscle.] 

Reflect  the  genio  and  mylo-hyoid  muscles  towards  the 
lower  jaw,  we  thus  expose  superiorly  the  membrane  of 
the  mouth,  with  the  sublingual  gland  attached  to  it,  close 
to  which  is  the  gustatory  nerve  ;  inferior  to  this  the  Whar- 
tonian  duct  is  seen,  and  nearer  to  the  os  hyoides  is  the 
lingual  nerve,  from  which  a  plexus  extends  to  the  gustato- 
ry ;  the  hyo  and  genio-hyo-glossi,  and  the  three  styloid 
muscles  are  also  now  exposed. 

The  sublingual  is  the  third  and  smallest  of  the  salivary 
glands,  oblong,  placed  beneath  the  anterior  and  lateral 
part  of  the  tongue,  covered  superiorly  by  the  mucous 
membrane,  to  which  it  adheres,  and  resting  inferiorly  on 
the  mylo-hyoid,  is  in  contact  internally  with  the  genio- 
hyo-glossus,  and  is  connected  externally  to  the  deep  pro- 
cess of  the  submaxillary  gland.  This  gland  opens  by 
several  small  ducts,  some  of  which  join  the  Whartonian 
canal,  others  perforate  the  mucous  membrane  of  the  mouth, 
between  the  tongue  and  inferior  canine,  and  bicuspid  teeth 
by  small  openings,  which  may  'be  observed  on  a  sort  of 
crest  or  fdld  of  the  mucous  membrane  in  this  situation. 
The  three  salivary  glands,  though  generally  separated 
from  each  other,  yet  are  in  some  cases  so  joined  together 
as  to  resemble  one  irregular  glandular  mass,  the  parotid 
being  united  to  'the  submaxillary  behind  the  angle  of 
the  jaw,  and  the  latter  being  connected  to  the  sublingual 
around  the  mylo-hyoid  muscle. 

HYO-GLOSSUS  is  flat  and  thin,  arises  from  the  cornu  and 
part  of  the  body  of  the  os  hyoides,  ascends  a  little  out- 
wards, 'inserted  into  the  side  of  the  tongue.  Use,  to  render 
the  dorsum  of  the  tongue  convex  by  depressing  its  side  ; 
it  may  also  elevate  the  os  hyoides  and  base  of  the  tongue. 
This  muscle  is  covered  by  the  mylo-hyoid  in  part  and  by 
the  sublingual  gland  and  linguarnerve ;  it  lies  on  the  mid- 
dle constrictor  of  the  pharynx,  the  lingual  artery,  and  the 
substance  of  the  tongue. 

GENIO-HYO-GLOSSUS  is  triangular,  arises  by  a  small  ten- 
don from  an  eminence  inside  the  chin,  beneath  the  frrenum 


DUBLIN    DISSECTOR.  43 

linguae ;  thence  the  fibres  radiate,  the  superior  ascend  and 
turn  forwards  towards  the  tip  of  the  tongue,  the  middle 
also  ascend  some  inclining  forwards,  others  backwards ; 
the  inferior  and  posterior  pass  backwards  and  downwards 
to  the  base  of  the  os  hyoides. — Inserted  into  the  mesial 
line  of  the  tongue  from  the  apex  to  the  base,  and  into  the 
body  or  lesser  cornu  of  the  os  hyoides.  Use,  the  posterior 
fibres  can  draw  the  os  hyoides  towards  the  chin,  and  thus 
protrude  the  tongue  from  the  mouth,  the  anterior  can  draw 
back  the  tongue,  and  bend  its  tip  down  towards  the  frse- 
num,  the  middle  portion  can  depress  the  middle  of  the 
tongue  and  make  it  concave  from  side  to  side  ;  it  can  also 
draw  it  forwards  so  as  to  enlarge  the  opening  of  the  fauces. 
This  muscle  is  therefore  used  in  mastication  and  degluti- 
tion, also  in  the  articulation  of  several  letters.  The  sever- 
al muscles  last  described  cover  this  muscle  externally,  in- 
ternally it  is  in  contact  with  its  fellow. 

LINGUALIS  is  a  fasciculus  of  fibres  taking  a  longitudinal 
course  on  the  inferior  surface  of  the  tongue  from  the  base 
to  the  apex,  and  intermixing  with  the  muscles  on  either 
side,  so  that  it  appears  as  being  derived  from  these  rather 
than  a  distinct  muscle ;  the  fibres  are  attached  through 
their  whole  length,  and  are  mixed  with  a  soft  fatty  sub- 
stance ;  anteriorly  they  are  broader  and  more  distinct ; 
they  are  situated  between  the  genio-hyo-glossus  internally, 
and  the  hyo  and  stylo-glossus  externally.  Use,  to  shorten 
the  tongue  and  bend  the  tip  downwards  and  to  one  side. 
External  to  the  muscles  now  described,  we  see  the  three 
styloid  muscles. 

STYLO-HYOIDEUS  arises  from  the  outer  side  of  the  styloid 
process  near  its  base,  descends  obliquely  forwards  parallel 
to  the  posterior  belly  of  the  digastric,  whose  tendon  gen- 
erally perforates  this  muscle,  inserted  into  the  cornu  and 
body  of  the  os  hyoides  and  into  the  fascia,  which  connects 
the  digastric  tendon  to  this  bone.  Use,  to  co-operate  with 
the  posterior  part  of  the  digastric,  in  raising  and  drawing 
back  the  os  hyoides  and  tongue.  This  muscle  is  nearly 
superficial,  but  at  first  is  covered  by  the  parotid ;  the  di- 
gastric lies  to  its  external  side  and  the  external  carotid  ar- 
tery to  its  internal :  this  vessel  is  posterior  to  the  lower 
part  of  the  muscle,  but  anterior  to  its  origin  ;  a  ligament 
often  accompanies  the  stylo-hyoid  muscle,  from  the  styloid 
process  to  the  cornu  of  the  os  hyoides ;  it  is  named  the 
stylo-hyoid  ligament,  and  is  sometimes  ossified. 

[Variety.    This  muscle  is  often  double.] 

Raise  the  digastric  and  stylo-hyoid,  and  we  see  the  re- 
maining styloid  muscles. 


44  DUBLIN    DISSECTOR. 

STYLO-GLOSSUS  arises  tendinous  and  narrow  from  the  in- 
ner side  of  the  styloid  process  near  its  point,  and  from  the 
stylo-maxillary  ligament;  descends  obliquely  forwards 
and  inwards,  and  is  inserted  into  the  side  of  the  tongue ;  its 
fibres  overlap  and  unite  with  those  of  the  hyo-glossus,  and 
can  be  traced  as  far  as  the  tip. —  Use,  to  draw  the  tongue 
backwards,  and  to  one  side,  and  to  raise  the  tip  behind  the 
upper  incisor  teeth.  It  is  covered  by  the  sub-maxillary 
and  lingual  glands,  by  the  gustatory  nerve  and  mucous 
membrane. 

[Variety.  This  muscle  has  been  found  double  on  both  sides.] 
STTLO-PHARTNGEUS,  long  and  narrow,  arises  from  the 
back  part  of  the  root  of  the  styloid  process,  descends  in- 
wards and  backwards,  passes  between  the  superior  and 
middle  constrictors  of  the  pharynx,  with  which  it  mixes  ; 
is  inserted  with  these  into  the  side  of  the  pharynx,  also  into 
the  cornu  of  the  os  hyoides  and  thyroid  cartilage.  Use,  to 
elevate,  dilate,  and  draw  forwards  the  pharynx,  so  as  to 
receive  the  food  from  the  tongue.  It  is  covered  by  the  sty- 
lo-hyoid,  middle  constrictor  and  external  carotid,  and  it 
lies  on  the  superior  constrictor,  internal  carotid,  sympa- 
thetic and  par  vagum ;  the  glosso-pharyngeal  nerve  winds 
round  it. 


SECTION  II. 

DISSECTION  OF  THE    VESSELS  AND    NERVES    OF  THE    NECK. 

THE  arteries  which  are  met  with  in  dissecting  the  neck 
are  the  carotid  and  subclavian  of  each  side,  and  their  sev- 
eral branches ;  the  veins  are  the  external  and  internal  ju- 
gular and  subclavian  ;  the  nerves  are  the  gustatory  branch 
of  the  fifth,  the  eighth,  and  the  ninth  pair,  the  sympathetic 
and  the  anterior  branches  of  the  eight  cervical  and  first 
dorsal  spinal  nerves.  The  right  carotid  artery  arises  from 
the  arteria  innominata,  behind  the  right  sterno-clavlcular 
articulation  ;  'the  left  carotid  arises  from  the  upper  part  of 
the  arch  of  the  aorta;  in  other  respects  these  arteries  are 
similar ;  both  ascend  'by  the  side  of  the  trachea  and  lar- 
ynx, surrounded  by  a  sheath  of  cellular  membrane,  on  the 
forepart  of  Which  are  seen  the  branches  of  the  descendens 
noni  nerve ;  behind  the  sheath  lies  the  sympathetic,  and 
within  it  are  the  jugular  vein,  lying  to  the  outside  of  the 
artery,  and  the  par1  vagum  nerve,  between,  and  rather  be- 
hind both  these  vessels;  opposite  the  os  hyoides  each  car- 


DUBLIN    DISSECTOR.  45 

otid  divides  into  two  branches,  viz.  the  internal  and  exter- 
nal ;  the  internal  carotid  artery  is  the  larger  branch,  lies 
deeper  in  the  neck,  and  more  external ;  it  ascends  along 
the  forepart  of  the  transverse  processes  of  the  vertebrae  to 
the  base  of  the  cranium,  enters  this  cavity,  through  the 
foramen  caroticum  in  the  temporal  bone,  and  is  distributed 
to  the  brain.  The  external  carotid  artery  ascends  towards 
the  parotid  gland,  being  crossed  by  the  digastric  and  stylo- 
hyoid  muscles,  and  by  the  lingual  and  portio  dura  nerves  ; 
in  this  course  it  gives  off  several  branches,  viz.  the  supe- 
rior thyroid,  lingual,  labial  or  facial,  auricular,  occipital, 
pharyngeal,  transverse  facial,  internal  maxillary  and  tem- 
poral. 

The  Subclavian  arteries  are  situated  at  the  inferior  and 
lateral  part  of  the  neck ;  the  right  arises  from  the  .arteria 
innominata,  the  left  from  the  posterior  part  of  the  arch  of 
the  aorta ;  each  subclavian  artery  passes  upwards  and  out- 
wards to  the  anterior  scalenus,  behiad  which  it  passes ;  it 
then  turns  downwards  and  outwards  behind  the  clavicle, 
and  over  the  first  rib  into  the  axilla;  the  difference  in  the 
origin  causes  an  important  difference  in  the  situation  and 
connexions  of  the  right  and  left  subclavian  in  the  early 
part  of  their  course ;  the  right  being  shorter  and  nearly 
transverse,  lies  higher  in  the  neck,  and  more  superficial 
than  the  left,  which  arises  deep  in  the  thorax,  out  of  which 
it  ascends  perpendicularly  before  it  turns  outwards  to  pass 
between  the  scaleni ;  after  this  point,  these  vessels  are  sim- 
ilar in  every  respect ;  each  gives  off  the  following  branch- 
es, viz.  arteria  vertebralis,  mammaria  interna,  axis  thyroi- 
dea,  cervicalis  profunda,  and  intercostalis  superior. 

The  external  jugular  vein  has  been  already  noticed 4  the 
internal  jugular  vein  of  each  side  commences  at  the  termi- 
nation of  the  lateral  sinus  in  the  foramen  lacerum  poste- 
rius,  descends  along  the  outer  side,  first,  of  the  internal, 
and  afterwards  of  the  common  carotid  artery,  and  at  the 
inferior  part  of  the  neck,  joins  the  subclavian  vein,  which 
returns  the  blood  from  the  upper  extremity,  and  accom- 
panies the  subclavian  artery  ;  the  junction  of  each  jugular 
!  and  subclavian,  which  is  posterior  to  the  sternal  end  of 
each  clavicle,  forms  the  right  and  left  vena3  innominatse  ; 
these  veins  enter  the  chest,  and  uniting,  commence  the  su- 
I  perior  vena  cava,  as  will  be  seen  in  the  dissection  of  the 
I  thorax. — (For  the  more  particular  description  of  the  ves- 
!  sels  of  the  neck,  see  the  anatomy  of  the  vascular  system.) 
The  gustatory  nerve  is  the  principle  branch  of  the  inferior 
'maxillary,  or  third  division  of  the  fifth  pair  ;  it  is  seen,  on 
dividing  the  mylo-hyoid,  taking  an  arched  course  parallel 
to  the  stylo-glossus  muscle,  from  within  the  angle  of  the 


46  DUBLIN    DISSECTOR. 

jaw  towards  the  tip  and  side  of  the  tongue  ;  it  accompanies 
the  Whartonian  duct,  and  rises  above  the  sublingual  gland, 
between  it  and  the  tongue ;  it  gives  branches  to  the  sub- 
maxillary  and  sublingual  glands,  and  terminates  in  fine 
filaments,  which  are  lost  in  the  papillae  beneath  the  mu- 
cous membrane,  covering  the  sides  and  tip  of  the  tongue. 
The  chorda  tympani  joins  it  near  the  condyle,  and  parts 
from  it  opposite  the  angle  of  the  lower  maxilla ;  this  deli- 
cate nerve  then  swells  into  a  small.ganglion,  whose  branches 
pass  into  the  submaxillary  gland.  The  eighth  pair  of  nerves 
leave  the  cranium  by  the  foramen  lacerum  posterius,  ante- 
rior to  the  jugular  -vein ;  it  immediately  separates  into  its 
three  portions,  the  internal  or  glosso-pharyngeal,  the  exter- 
nal or  spinal  accessory,  and  the  middle  or  par  vagum.  The 
glosso-pharyngeal  is  connected  to  the  stylo-pharyngeus  mus- 
cle, its  name  denotes  its  destination ;  the  arch  which  it 
forms,  as  it  runs  to  the  base  of  the  tongue,  is  inferior  to 
and  deeper  in  the  neck  than  the  gustatory  nerve.  The 
spinal  accessory  nerve  separates  from  the  par  vagum,  and  in 
general  winds  round  behind  the  internal  jugular  vein,  per- 
forates the  sterno-mastoid  muscle,  as  was  before  mentioned, 
and  distributes  its  branches  to  it  arid  to  the  trapezius  ;  seve- 
ral of  these  also  communicate  with  the  cervical  plexus, 
and  descend  towards  the  acromion.  The  par  vagum  or 
pneumogastric  descends  along  the  neck,  between,  and  rather 
behind  the  carotid  artery  and  jugular  vein,  and  enclosed  in 
their  sheath  ;  it  then  passes  through  the  thorax,  and  termi- 
nates on  the  stomach.  The  cervical  portion  only  of  this 
nerve  is  to  be  observed  at  present;  from  it  arises  several 
tranches,  viz.  communicating  branches  to  join  the  sympa- 
thetic and  lingual;  pharyngeal  branches  to  the  side  of  the 
pharynx ;  superior  laryngeal  nerve,  which  takes  an  arched 
course  behind  the  great -vessels  to  the  thyroid  cartilage,  and 
is  distributed  to  the  upper  part  of  the  larynx ;  and  small 
cardiac  branches,  which  join  similarly  named  branches  of 
the  sympathetic  nerve.  At  the  inferior  part  of  the  neck, 
on  each  side  of  the  trachea,  a  large  nerve,  the  inferior  la- 
ryngeal or  recurrent  nerve,  is  seen ;  this  is  also  a  branch  of! 
the  par  vagum.  On  the  right  side,  this  nerve  arises  at  the 
lower  part  of  the  neck,  turns  round  the  subclavian  artery, 
and  passing  behind  it  and  the  carotid,  pursues  its  course 
upwards  and  inwards  behind  the  thyroid  body  to  the  lower 
and  back  part  of  the  larynx ;  on  the  left  side  the  recurrent  I 
nerve  arises  in  the  thorax,  opposite  the  lower  part  of  the 
arch  of  aorta,  under  which  it  passes,  and  then  attaching 
itself  to  the  forepart  of  the  oesophagus,  ascends  to  the 
larynx,  to  the  muscles  of  which  it  is  distributed  like  that 
of  the  opposite  side.  At  the  inferior  part  of  the  neck,  the 


DUBLIN    DISSECTOR.  47 

eighth  pair  of  nerves  enter  the  thorax ;  that  of  the  right 
side  passes  anterior  to  the  subclavian  artery,  crossing  it  at 
a  right  angle ;  that  of  the  left  side  descends  anterior  but 
parallel  to  the  left  subclavian  artery.  The  ninth  pair,  or 
lingual  nerve,  leaves  the  cranium  by  the  anterior  condyloid 
hole  in  the  occipital  bone,  descends  forwards  and  inwards, 
nearly  parallel  to  the  digastric  muscle,  and  is  distributed 
to  the  muscles  of  the  tongue ;  the  arch  which  the  course 
of  this  nerve  describes  is  parallel,  but  inferior  to  that  of 
the  gustatory.  From  the  convexity  of  this  arch  a  long 
branch  arises,  the  descendens  noni;  this  descends  along  the 
forepart  of  the  sheath  of  the  carotid  artery,  communicates 
with  the  second  and  third  cervical  nerves  about  the  middle 
of  the  neck,  and  is  distributed  to  the  sterno-hyoid  and 
thyroid  muscles :  in  some  cases  this  nerve  descends  within 
the  sheath  behind  the  vein.  The  sympathetic  nerve  may  be 
found  descending  along  the  vertebras  posterior  to  the  car- 
otid artery  :  this  nerve  commences  at  the  base  of  the  cra- 
nium, in  a  long,  oval,  red  swelling,  the  superior  cervical  gan- 
glion, which  extends  as  low  as  the  third  cervical  vertebra ; 
from  this  the  nerve  becoming  very  small,  descends  almost 
vertically,  and  in  general  opposite  the  fifth  cervical  verte- 
bra, it  forms  a  second  swelling,  called  the  middle  cervical 
ganglion ;  from  this,  the  small  nervous  chord  continues  its 
course  down  the  neck,  and  opposite  the  seventh  cervical 
vertebra,  and  the  neck  of  the  first  rib,  it  expands  into  a 
large  irregular  swelling,  the  inferior  cervical  ganglion,  from 
the  lower  part  of  which  the  nerve  descends  into  the  thorax. 
(For  the  particular  description  of  the  branches  of  the  sym- 
pathetic, as  well  as  of  the  cerebral  nerves,  met  with  in  the 
dissection  of  the  neck,  see  the  Anatomy  of  the  Nervous  System.) 
On  the  side  of  the  neck  are  seen  numerous  branches  of  the 
cervical  spinal  nerves ;  there  are  eight  pair  of  cervical  nerves  ; 
the  first,  or  suboccipital,  is  very  small ;  the  eighth  is  very- 
large  ;  the  first  leaves  the  spinal  canal  between  the  occi- 
pital bone  and  the  atlas ;  and  the  eighth  between  the  last 
cervical  and  first  dorsal  vertebra :  these  cervical  nerves  all 
divide  into  a  posterior  and  anterior  branch,  the  former  are 
distributed  to  the  muscles  and  integuments,  on  the  back  of 
the  neck ;  the  anterior  branches  of  the  first,  second,  third, 
and  fourth,  communicate  with  each  other,  and  give  origin 
to  several  branches,  which  again  unite  with  each  other, 
and  constitute  the  cervical  plexus  ;  this  plexus  is  between  the 
mastoid  and  trapezius  muscles ;  it  sends  off  several  branch- 
es, which  are  entangled  with  much  cellular  membrane, 
and  several  absorbent  ganglia :  the  anterior  branches  of 
the  four  inferior  cervical  nerves  with  that  of  the  first  dor- 
sal, unite  and  form  the  brachial  plexus ;  this  is  situated  at 


48  DUBLIN    DISSECTOR. 

the  lateral  and  inferior  part  of  the  neck,  and  accompanies 
the  subclavian  artery  beneath  the  clavicle  into  the  axilla, 
in  whicH  region  the  plexus  divides  into  several  branches 
to  supply  the  upper  extremity  and  the  muscles  on  the  par- 
ietes  of  the  thorax.  In  the  inferior  and  lateral  part  of  the 
neck,  on  each  side,  the  phrenic  nerve  is  also  seen ;  this  ari- 
ses by  several  fine  filaments,  from  the  third,  fourth,  and 
fifth  cervical  nerves ;  the  phrenic  nerve  descends  obliquely 
inwards  along  the  anterior  scalenus  muscle,  enters  the  tho- 
rax between  the  subclavian  vein  and  artery,  and  is  distrib- 
uted to  the  diaphragm.  Previous  to  examining  the  deep 
muscles  of  the  neck,  the  student  should  study  the  anatomy 
of  the  mouth,  pharynx,  and  larynx. 


SECTION  III. 

DISSECTION    OF    THE    MOUTH,    PHARYNX,    AND    LARYNX. 

THE  cavity  of  the  mouth  may  be  exposed  by  dividing 
the  commissure  of  the  lips,  and  the  cheek  of  one  side,  and 
removing  a  small  portion  of  the  side  of  the  lower  jaw ; 
draw  forward  the  tongue  with  a  tenaculum,  and  cleanse 
the  parts  very  well.  The  mouth  is  bounded  anteriorly  by 
the  lips,  superiorly  by  the  hard  and  soft  palate,  laterally 
by  the  cheeks,  inferiorly  by  the  tongue,  and  mucous  mem- 
brane  reflected  from  it  to  the  gums  ;  posteriorly  it  commu- 
nicates with  the  pharynx  :  this  opening  is  named  the  isth- 
mus faucium;  it  is  bounded  above  by  the  velum  and  uvula, 
below  by  the  tongue,  on  each  side  by  the  arches  of  the  pa- 
late. The  anterior  part  of  the  palate,  or  hard  palate,  is 
formed  of  the  palate  plates  of  the  maxillary  and  palate 
bones,  covered  by  mucous  membrane  and  glands  ;  the  pos- 
terior part  of  the  palate  or  soft  palate,  or  velum  pendulum, 
consists  of  a  dense  aponeurosis,  and  of  several  muscles 
and  glands,  enclosed  in  mucous  membrane ;  the  cheeks  are 
formed  of  mucous  membrane,  covered  by  the  buccinator 
and  a  quantity  of  fat ;  several  small  mucous  glands  lie  be- 
tween the  membrane  and  this  muscle,  and  towards  the  up- 
per and  back  part  on  each  side  we  perceive  the  small 
opening  of  Steno's  duct.  The  mouth  is  lined  throughout 
by  mucous  membrane,  which  is  continuous  with  the  cutia 
on  the  lips,  and  extends  posteriorly  through  the  pharynx, 
whence  it  ascends  to  line  the  nares,  the  Eustachian  tube 
and  tympanum  on  each  side,  and  descends  to  line  the  oeso- 
phagus and  larynx ;  as  it  is  reflected  from  one  surface  to 
another,  it  forms  folds  or  fraena,  as  between  the  lips  and 


ly 
th 


DUBLIN    DISSECTOR.  49 

alveoli,  and  beneath  the  tongue  ;  at  the  sides  of  the  fauces, 
also,  it  forms  two  semilunar  folds  on  each  side,  called  the 
pillars  or  arches  of  the  palate  ;  these  folds  enclose  muscu- 
lar fibres,  which  we  shall  examine  afterwards. 

[The  mucous  membrane  lining  ths  mouth,  tongue,  pharynx  and 
oesophagus,  is  furnished  v/ith  a  delicate  cuticle  or  epithelium,  which 
terminates  at  the  cesophageal  opening  of  the  stomach  ;  the  existence 
of  this  membrane,  is  demonstrated  by  its  occasional  separation  in 
shreds,  in  fevers,  or  from  taking  a  quantity  of  hot  fluid  into  the 
mouth,  it  is  also  shown  by  maceration.] 

On  looking  into  the  mouth,  either  in  the  living  or  dead 
subject,  the  following  objects  strike  the  attention  ;  inferior- 

the  tongue  and  teeth  ;  laterally  the  cheeks  ;  posteriorly 

e  back  part  of  the  pharynx  ;  superiorly  the  hard  and 
soft  palate,  from  the  centre  of  the  latter,  the  uvula,  and 
from  the  sides,  the  pillars  or  arches  descending  to  the 
tongue  and  pharynx  ;  in  the  recess  between  these  pillars 
on  each  side  the  tonsil  or  amygdala  is  also  seen  ;  lastly,  if 
the  tongue  be  drawn  forward,  the  epiglottis  comes  into 
view. 

The  tongue  is  of  a  triangular  shape  :  its  base,  thick  and 
broad,  is  connected  to  the  epiglottis  and  palate  by  mucous 
membrane,  and  to  the  os  hyoides  and  inferior  maxilla  by 
muscles  ;  the  apex  is  thin,  and  unattached  ;  that  portion 
between  it  and  the  base  is  named  the  body  of  the  tongue  ; 
all  the  upper  surface,  the  sides,  and  about  one-third  of  its 
inferior  surface*  are  covered  by  mucous  membrane,  which 
is  very  rough  superiorly,  from  the  number  of  papillce  that 
project  througJi  it  ;  anteriorly,  these  papillae  are  small, 
conical,,  aad  connected  witli  the  terminations  of  the  nerves 
of  taste  ;  posteriorly  they  arc  large,  round,  fungiform,  len- 
tieVilar,  and  very  irregular;  these  are  small  glands  which 
open  on  the  mucous  surface  ;  near  the  epiglottis  these  glan- 
dular papilla  are  often  observed  to  have  a  peculiar  ar- 
rangement, like  the  letter  v,  the  concavity  turned  forwards  ; 
"behind  the  apex  of  this  angle,  a  deep  depression  (foramen 
coecum)  is  observable  ;  this  contains  some  mucous  folli- 
cles ;  a  superficial  groove  runs  along  the  dorsum  of  the 
tongue,  one  more  distinct  exists  along  the  inferior  surface, 
sa  that  this  organ  is  divided  by  the  mesial  line,  into  two 
symmetrical  portions  ;  accordingly,  in  paralysis,  one  side 
only  of  this  organ  is  frequently  found  affected.*  The  sub- 

*  In  hcmiplegia,  when  the  muscles  of  one  side  of  the  face  are  paralysed,  it  has 
l>pt  u  remarked,  that  if  the  tongue  be  protruded,  the  apex  will  he  directed  towards 
the  affected  side  ;  this  phenomenon,  which  is  only  an  apparent  exception,  depends 
in  the  action  of  the  genio-hyo-glossus  muscle  of  the  healthy  side,  which  will  pull 
the  base  of  the  tongue  on  that  side  towards  the  chin,  and  must  therefore  turn  the 
point  to  the  opposite  side. 

5 


50  DUBLIN    DISSECTOR. 

stance  of  the  tongue  is  composed  of  adeps  blended  with 
numerous  muscular  fibres  derived  from  the  stylo,  hyo,  ge- 
nio-hyo-glossi,  and  linguales  muscles,  and  of  many  other 
fleshy  fibres  which  do  not  properly  belong  to  any  of  these 
[viz.  the  superficial  transverse,  and  vertical  lingual  mus- 
cles:]  two  large  arteries  (lingual)  and  six  considerable 
nerves  (the  gustatory,  the  lingual,  and  the  glosso-pharyn- 
geal,  on  each  side)  supply  this  organ.  The  tongue  is  not 
only  the  organ  of  taste,  but  by  its  great  mobility  it  assists 
in  speech,  in  suction  and  in  deglutition.  The  fifth  pair  of 
nerves  endow  the  tongue  with  sensation  and  with  the  sense 
of  taste,  the  ninth  with  mobility,  and  the  eighth  supply  its 
base  with  sensation,  and  connect  the  motions  of  this  organ 
with  those  of  the  pharynx  and  stomach. 

The  tongue  is  subject  to  many  morbid  changes,  viz.  in- 
flammation, acute  or  chronic,  causing  great  and  dangerous, 
and  sometimes  fatal  enlargement ;  tumors  of  different  kinds 
occur  here,  also  ulceration,  cancerous,  syphilitic,  apthous, 
&c. ;  portions  of  this  organ  can  be  removed  with  safety, 
either  by  ligature  or  excision. 

[The  tongue  is  sometimes  the  seat  of  congenital  malformations ; 
its  tip  is  sometimes  bifurcated,  sometimes  nipple  shaped  ;  the  organ 
is  sometimes  entirely  wanting,  sometimes  double.  The  fhenum 
lingucB  (a  vertical  fold  of  the  mucous  membrane,  as  it  is  reflected 
from  the  inferior  surface  of  the  tongue  to  the  floor  of  the  mouth,)  is 
sometimes  too  long,  antero-posteriorly,  or  too  short  vertically,  con. 
stituting  the  tongue  tie,  which  interferes  with  nursing  in  the  infant, 
and  with  distinct  articulation  at  a  subsequent  period  :  this  is  easily 
relieved,  by  dividing  the  framum  for  a  line  or  two.  It  has  been  sup. 
posed  that  in  excising  one  lateral  half  of  the  tongue  there  would  be 
serious  hemorrhage,  in  consequence  of  a  free  anastomosis  of  the  arte- 
ries of  the  two  sides  ;  that  this  free  anastomosis  does  not  exist,  is 
proved  by  minute  injection,  most  of  the  vessels,  terminating  at  the 
middle  septum  of  the  tongue  ;  it  is  also  proved  by  the  fact,  that  the 
lateral  excision  of  the  tongue,  has  been  accomplished,  without 
hemorrhage,  by  first  tying  the  trunk  of  the  lingual  artery,  just  at 
the  cornu  of  the  os-hyoides.] 


SECTION  IV. 

DISSECTION    OF    THE    PHARYNX. 

To  obtain  a  view  of  the  muscles  of  the  pharynx  and  pa- 
late, the  student  may  now  make  the  following  dissection : 
divide  the  trachea  and  oesophagus  in  the  lower  part  of  the 


DUBLIN    DISSECTOR.  51 

neck  ;  detach  them  from  the  vertebrae,  to  which  they  are 
loosely  connected;  draw  forward  these  organs,  together 
with  the  vessels  and  nerves  on  either  side ;  place  the  saw 
flat  on  the  bodies  of  the  vertebrae ;  insinuate  its  edge  be- 
tween the  styloid  and  mastoid  processes  on  each  side,  and 
make  a  vertical  section  of  the  head :  we  have  thus  the  face 
and  anterior  part  of  the  cranium  separated  from  the  verte- 
bral column  ;  or,  should  it  be  desirable  to  preserve  the 
cranium,  we  may  separate  the  occipital  bone  from  the  at- 
las, and  then  remove  from  the  subject  the  whole  head,  to- 
gether with  the  organs  we  wish  to  examine ;  distend  the 
pharynx  with  hair  or  tow,  and  remove  some  of  the  loose 
cellular  tissue  connected  to  it 

The  pharynx  is  a  large,  muscular,  and  membranous  bag. 
extending  from  the  base  of  the  cranium  to  the  fourth  or 
fifth  cervical  vertebra,  where  it  ends  in  the  oesophagus  ;  it 
is  placed  behind  the  nose,  mouth,  and  larynx ;  is  some- 
what of  an  oval  form,  the  largest  part  being  opposite  the 
os  hyoides,  and  the  smaller  extremity  joining  the  oesopha- 
gus. The  pharynx  is  attached  superiorly  and  posteriorly 
to  the  cuneiform  process,  by  an  aponeurosis,  which  is  very 
strong  in  the  middle  line,  laterally  by  a  thinner  aponeu- 
rosis to  the  petrous  bone,  and  anteriorly,  by  fleshy  fibres 
to  the  internal  pterygoid  plate  and  hamular  process,  and 
to  the  posterior  part  of  the  mylo-hyoid  ridge  of  the  lower 
maxilla ; — the  pharynx  is  connected  posteriorly  to  the  ver- 
tebra, and  to  the  deep  muscles  of  the  neck,  by  loose  reti- 
cular  membrane;  anteriorly  it  is  attached  by  mucous 
membrane  and  muscular  fibres  to  the  cornua  of  the  os  hy- 
oides and  thyroid  cartilage,  and  to  the  sides  of  the  cricoid, 
behind  which  the  pharynx  abruptly  contracts  and  ends  in 
the  oesophagus  :  on  either  side  of  the  pharynx,  and  loosely 
connected  to  it,  is  the  sheath  of  the  carotid  artery  with  its 
.accompanying  nerves.  The  muscular  fibres  which  cover 
the  back  and  sides  of  the  pharynx,  are  named  constrictor 
muscles  ;  they  are  symmetrical,  and  are  three  in  number 
•on  each  side,  they  are  named  the  superior,  middle,  and  in- 
j  ferior ;  they  overlap  each  other,  the  inferior  being  most  su- 
}  perficial,  the  middle  next,  and  the  superior  the  deepest ; 
!  the  constrictor  muscles  of  opposite  sides  have  one  common 
I  insertion  into  the  middle  tendinous  line,  or  raphe  on  the  back 
I  part  of  the  pharynx,  which  line  is  very  strong  and  distinct 
i  superiorly,  being  inserted  into  the  cuneiform  process,  but 
interiorly  it  is  weak  and  often  indistinct. 

CONSTRICTOR  PHARYNGIS  INFERIOR  is  somewhat  square, 
I  arises  from  the  side  of  the  cricoid  cartilage,  from  the  infe- 
'irior  cornu  and  posterior  part  of  the  ala  of  the  thyroid 
•cartilage,  external  to  the  crico-thyroid  andthyreo-hyoid  ; 


52  DUBLIN    DISSECTOR. 

the  superior  fibres  ascend  obliquely,  and  overlap  tke 
middle  constrictor ;  the  inferior  fibres  run  circularly  and 
overlap  the  resophagus;  inserted  along  with  that  of  the 
opposite  side  into  the  middle  line  on  the  back  of  the 
pharynx ;  its  origin  is  covered  by  the  sterno-thyroid  mus- 
cle, and  the  thyroid  body ;  this  muscle  lies  on  the  mucous 
membrane,  except  its  superior  fibres,  which  are  separated 
from  it  by  the  middle  constrictor.  The  inferior  laryngeal 
or  recurrent  nerve  passes  beneath  its  lower  edge,  and  the 
superior  laryngeal  beneath  its  upper. 

CONSTRICTOR  PHARYNGIS  MEDIUS  is  of  a  triangular  form, 
arises  from  the  cornu  and  appendix  of  the  os  hyoides,  also 
from  the  stylo-hyoid  and  posterior  thyreo-feyoid  ligaments  ; 
its  fibres  expand  on  the  back  of  the  pharynx,  the  superior 
ascend  to  the  occipital  bone,  the  middle  run  transversely, 
and  the  inferior  descend  beneath  the  lovrer  constrictor, 
inserted  into  the  mesial  tendinous  line  or  rapfee,  and  into 
the  cuneiform  process.  The  lingual  artery  and  hyo-glos- 
sus  muscle  are  connected  to  tb.e  origin  of  this  muscle, 
which  part  is  separated  from  the  inferior  constrictor  by 
the  superior  laryngeal  nerve  and  cornu  of  the  thyroid 
cartilage,  and  from  the  superior  constrictor  by  the  stylo- 
pharyngeus  muscle  and  glosso-pharyngeal  nerve ;  on  di- 
viding the  edge  of  this  muscle,  the  STYIJO-PHARYNGEUS  ap- 
pears ;  it  arises  from  the  root  of  the  styloid  process,  des- 
cends to  the  side  of  the  pharynx,  where  it  expands  between 
the  superior  and  middle  constrictors,  and  is  inserted  beneath 
the  latter  partly  into  the  submucous  tissue,  and  partly  into 
the  cornu  of  the  thyroid  cartilage,  Cse,  to  elevate,  dilate, 
shorten,  and  draw  forwards  the  pharynx,  in  order  to  re- 
ceive the  food  from  the  tongue,  it  will  also  raise  the  larynx : 
divide  the  stylo-pharyngeus,  and  the  superior  constrictor 
will  be  exposed. 

CONSTRICTOR  PHARTNGIS  SUPERIOR,  surrounds  the  superior 
part  of  the  pharynx,  arises  by  a  dense  aponeurosis  from 
the  petrous  bone,  which  soon  becomes  connected  with  the 
next  origin,  which  is  fleshy,  from  the  lower  part  of  the 
internal  pterygoid  plate  and  hamular  process,  also  from 
the  intermaxillary  ligament,  (see  page  7,)  which  connects 
it  to  the  buccinator  muscle,  from  the  posterior  third  of  the 
mylo-hyoid  ridge,  and  from  the  side  of  the  base  of  the 
tongue  ;  all  the  fibres  take  a  semicircular  course  backwards 
and  inwards,  and  are  inserted  into  the  cuneiform  process 
and  into  the  middle  tendinous  line  on  the  back  of  the 
pharynx.  The  superior  constrictor  is  covered  by  the  sty- 
loid muscles  and  by  the  great  vessels  and  nerves,  and  in- 
feriorly  by  the  middle  constrictor,  from  which  the  stylo- 
pharyngeus  and  glosso-pharyngeal  nerve  separate  it :  be- 


DUBLIN    DISSECTOR.  53 

tween  the  attachment  to  the  petrous  bone  and  that  to  the 
occipital,  the  mucous  membrane  is  uncovered  by  muscular 
fibres  in  a  small  semicircular  space,  named  sinus  of  Morgag- 
ni  ;  this  is  beneath  the  cuneiform  process,  on  each  side  of 
the  middle  line,  and  corresponds  to  the  Eustachian  tubes ; 
between  the  temporal  and  pterygoid  attachments,  the  mus- 
cles of  the  velum  lie,  and  between  the  pterygoid  and 
maxillary  origins  the  internal  pterygoid  muscle  and  the 
gustatory  nerve  are  situated.  Use,  the  constrictors  dimin- 
ish the  capacity  of  the  pharynx,  and  by  the  successive 
contractions  of  each,  the  food  is  forced  into  the  oesophagus, 
the  complex  muscular  structure  of  the  pharynx  may  also 
assist  in  the  modulation  of  the  voice  and  in  the  production 
of  certain  sounds.  Open  the  pharynx  by  a  perpendicular 
incision  through  the  middle  tendinous  line ;  on  looking 
into  the  cavity  it  will  be  found  divided  by  the  velum  into 
iwo  portions,  a  superior  and  inferior  ;  seven  openings  also 
may  be  remarked  leading  from  it  in  different  directions, 
viz.  in  the  upper  and  nasal  portion  there  are  the  two  pos- 
terior nares,  and  on  the  side  of  each  of  these  is  the  open- 
ing of  the  Eustachian  tube ;  below  the  velum  is  the  isthmus 
faucium,  or  posterior  opening  of  the  mouth ;  below  and 
behind  the  tongue  is  the  opening  of  the  glottis ;  and  last- 
ly, the  termination  of  the  pharynx  in  the  oesophagus. 
The  openings  of  the  nares  are  of  an  oval  shape,  their  long 
diameter  being  vertical ;  the  body  of  the  sphenoid  bone 
bounds  them  superiorly,  the  palate  bones  inferiorly,  the 
internal  pterygoid  plates  externally,  and  the  vomer  sepa- 
rates them  from  each  other :  through  these  openings  the  air 
generally  passes  during  respiration.  The  Eustachian  tubes 
open  on  each  side  of  the  posterior  nares,  behind  the  infe- 
rior spongy  bone;  they  are  circular,  and  look  forwards 
and  inwards  towards  the  septum  narium,  are  formed  of 
thick  cartilage,  covered  by  mucous  membrane ;  through 
these  air  is  admitted  from  the  nose  into  the  tympanum, 
to  support  the  membrana  tympani  on  its  inner  side.  The 
Eustachian  tube  must  be  again  examined  in  the  dissection 
of  the  organ  of  hearing.*  Beneath  the  velum  is  the  isth- 
mus faucium,  transversely  oval,  but  capable  of  great 
change  in  figure  and  size,  bounded  above  by  the  velum 
and  uvula,  below  by  the  tongue,  and  on  either  side  by  the 
pillars  or  arches  of  the  palate,  and  by  the  amygdalae.  The 
opening  of  the  glottis  or  superior  opening  of  the  larynx,  is 
at  the  lower  and  anterior  part  of  the  pharynx,  behind  the 


*  The  student  may  practice  the  introduction  of  a  probe  into  this  tube  :  slightly 
curve  a  blunt  probe,  pass  it  along  the  floor  of  the  nose  to  the  posterior  nares, 
.then  direct  its  extremity  upwards,  outwards,  and  backwards,  that  is,  towards  the 
ear,  and  it  will  enter  this  tube. 

5* 


54  DUBLIN    DISSECTOR. 

epiglottis,  and  rather  beneath  tfee  tongue ;  it  is  of  a  trian- 
gular form,  the  base  anteriorly,  formed  by  the  epiglottis  ; 
the  sides  are  composed  of  fcJ.ds  of  mucous  membrane, 
termed  aryteno-epiglottidean,  and  the  apex,  which  is  pos- 
teriorly, is  formed  by  the  appendices  of  the  arytenoid 
cartilages.  The  glottis,  which  will  again  be  considered  in 
speaking  of  the  larynx,  is  always  open,  except  in  the  act 
of  deglutition.  The  asopliage&l  opening  is  below  and  be- 
hind the  glottis ;  it  is  always  closed,  except  in  deglutition. 
The  student  should  next  examine  the  velum  pendulum  pa- 
lati, o?  palatum  molle. 


SECTION    V. 

DISSECTION    OF    THE   PALATE    AND    ITS  MUSCLES. 

THE  velum  pendvJum  palati  is  a  soft  moveable  substance, 
attached  superiorly  and  anteriorly  to  the  hard  palate  on 
each  side  of  the  tongue  and  pharynx,  and  posteriorly  and 
inferiorly  it  terminates  in  8.  thin  edge,  from  the  centre  of 
which  the  uvwia  descends,  thus  giving  a  lunated  appear- 
ance to  tfee  edge  of  the  velum  on  each  side  ;  these  crescen- 
tic  edges  are  named  the  half  arches  of  the  palate, 

[Being  two  in  number  on  each  side,  between  which  the  tonsils  are 
placed  5  the  space  bounded  anteriorly  and  posteriorly,  by  these  half 
arches,  or  pillars,  is  the  fauces,  *md  the  anterior  opening  into  this 
space  is  called  the  isthmiie .faucium.'-. 

The  velum  is  situated  obliquely,  its  fixed  edge  being  su- 
perior and  anterior  to  the  loose,  one  surface  looking  for- 
wards asd  downwards  towards  the  moulh  and  tongue,  the 
opposite  surface  looking  upwards  and  backwards  ;  during 
life  this  aspect  can  be  altered  by  the  auction  of  muscles, 
which  can  cither  elevate,  depress,  or  make  tense  the  velum. 
Beneath  the  mucous  membrane  of  the  velum  several  small 
glands  are  situated,  chiefly  on  the  inferior  surface.  The 
-a  vula  is  a  conical  prolongation  of  the  velum,  enclosing 
small  glands,  loose  cellular  membrane,  and  some  muscular 
fibres  ;  in  deglutition,  the  velum  and  uvula  are  raised  so  as 
to  touch  the  back  part  of  the  pharynx,  and  thus  they  are 
of  use  in  preventing  the  food  ascendmg  into  the  cppcr  or 
nasal  part  of  the  cavity,  from  which  it  might  regurgitate 
into  the  nates*  The  muscles  of  the  velum  or  soft  palate 
be  levator  and  tensor  palati,  the  moto  uvula?, 
palato-glossus  and  palato-pharyngeus. 


DUBLIN    DISSECTOR.  55 

LEVATOR-PALATI,  arises  narrow  from  the  petrous  bone,  in 
front  of  the  foramen  caroticum  and  behind  the  Eustachian 
tube,  descends  obliquely  inwards  and  backwards,  and  is 
inserted  broad  into  the  velum  near  its  centre ;  its  name  de- 
notes its  use.  It  is  situated  on  the  side  of  the  posterior 
nares,  its  insertion  intermixes  with  its  fellow  and  with  the 
other  muscles  of  the  palate. 

TENSOR-PALATI  vel  circumflexus  palati,  arises  fleshy  from 
a  depression  at  the  root  of  the  internal  pterygoid  plate, 
from  the  spinous  process  of  the  sphenoid,  and  from  the 
forepart  of  the  Eustachian  tube,  descends  between  the  in- 
ternal pterygoid  plate  and  muscle,  ends  in  a  flat  tendon, 
which  turns  round  the  hamular  process  inwards  to  the  vel- 
um, it  then  expands,  and  joins  that  from  the  opposite  side. 
Use,  to  make  tense,  the  velum  in  a  horizontal  direction  be- 
tween the  hamular  processes. 

MOTOR  UVULAE,  arises  from  the  posterior  extremity  or 
spine  of  the  palate  bones,  descends  close  to  its  fellow, 
along  the  median  line  of  the  velum,  and  is  inserted  into  the 
cellular  tissue  of  the  uvula.  Use,  to  raise  and  shorten  the 
uvula :  this  pair  of  muscles  are  so  close  that  they  appear 
but  as  one,  hence  they  have  sometimes  received  the  name 
of  azygos  uvula* 

PALATO-GLOSSXJS  vel  constrictor  isthrai  faucium,  or  thr 
anterior  arch  or  pillar  of  the  palate,  arises  from  the  inferi- 
or surface  of  the  velum,  descends  forwards  and  outwards, 
enclosed  in  a  fold  of  mucous  membrane  anterior  to  the 
tonsil.  Inserted  'into  the  side  of  the  tongue.  Use,  to  elevate 
•the  tongue  or  to  depress  the  velum ;  this  pair  of  muscles 
may  also  close  the  fauces. 

PALATO-PHARYNGEUS,  or  posterior  arch  of  the  palate,  a  ri- 
ces broad  from  the  inferior  surface  of  -the  palate,  arcfces 
downwards  and  backwards  behind  the  tonsil,  and  is  inser- 
ted into  the  side  and  back  of  the  pharynx,  and  into  the 
•-cornu  of  the  thyroid  cartilage,  its  fibres  mixing  with  those 
of  the  stylo-pharyngeus.  Cse,  to  elevate  the  pharynx,  like 
Uie  stylo-pharyngei  in  the  commencement  of  deglutition-; 
but  afterwards  to  depress  the  velum. 

The  tonsil  or  amygdala,  though  apparently  a  compact 
ftody,  is  formed  of  a  congeries  of  mucous  glands,  of  an  ir- 
Tegular  figure,  somewhat  oval,  the  larger  extremity  abova, 
placed  in°a  triangular  recess  between  the  pillars  of  the 
palate,  above  the  side  of  the  base  of  the  tongue,  covered 
internally  by  the  mucous  membrane,  and  externally  by  the 
'superior  constrictor  of  the  pharynx ;  small  holes  are  re- 
marked on  its  surface ;  these  lead  into  cells  from  which 
the  mucus  can  be  expressed. 

[The  tonsil  is  usually  described,  as  being  of  the  size  of  an  almond  : 


56  DUBLIN    DISSECTOR. 

it  is  from  six  to  eight  lines  in  length,  from  four  to  five  in  breadth, 
and  three  in  thickness,  and  is  of  a  reddish  grey  color.] 

The  amygdalae  are  very  vascular  and  secrete  a  viscid 
fluid,  which  being  pressed  out  in  the  moment  of  deglutition 
by  the  contraction  of  the  surrounding  muscles,  serves  to 
lubricate  the  alimentary  bolus  in  its  passage.  The  inter- 
nal carotid  artery  is  posterior  and  somewhat  external  to  it, 
the  external  carotid  is  also  to  its  outer  side,  and  the  facial 
artery,  just  before  it  enters  the  submaxillary  gland,  is  an- 
terior to  it ;  from  these  three  vessels,  this  gland  when  of  its 
healthy  size,  is  separated  by  the  superior  constrictor,  and 
by  a  considerable  interval  which  is  rilled  by  cellular  tissue, 
but  when  enlarged,  as  in  the  case  of  abscess,  it  comes  into 
such  close  contact  with  these,  particularly  with  the  inter- 
nal carotid,  that  there  is  some  danger  of  wounding  the  lat- 
ter in  opening  the  abscess  with  the  lancet. 

The  soft  palate  and  its  arches,  the  uvula  and  the  tonsils, 
are  liable  to  many  morbid  affections,  viz.  acute  inflamma- 
tion and  all  its  consequences ;  syphilitic  ulceration  very 
commonly  attacks  these  parts,  particularly  that  surface, 
towards  the  mouth  ;  polypi,  also,  are  not  unfrequently  pro- 
duced from  the  velum,  and  in  general  from  its  upper  or 
nasal  surface.  When  the  uvula  is  the  seat  of  inflamma- 
tion, its  pendulous  extremity  becomes  so  distended  by  se- 
rous infiltration,  that  its  figure  is  totally  changed,  and  it 
sometimes  interferes  so  much  with  deglutition  and  respi- 
ration, or  excites  such  irritation,  as  to  require  free  scarifi- 
cation, or  excision  of  its  lower  portion.  The  velum  is 
sometimes  found  cleft  at  birth  with  or  without  the  accom- 
panying similar  anormal  state  of  the  hard  palate  and  up- 
per lip. 

The  tonsil  is  very  subject  to  acute  inflammation  (cynan- 
che  tonsillaris)  ;  in  this  affection  it  enlarges  so  much  as  to 
impede  deglutition,  induce  deafness,  and  even  in  some -cases 
to  threaten  suffocation.  It  is  sometimes,  also,  the  seat  of 
chronic  enlargement,  to  such  a  degree,  as  to  require  the 
operation  of  removal ;  it  is  also  frequently  affected  with 
syphilitic,  ulceration. 

[The  tonsil  is  sometimes  the  seat  of  a  calcareous  concretion  ;  the 
chronic  cases  of  hard  enlarged  tonsils,  are  commonly  spoken  of  as 
schirrus ;  it  is  not  however  of  a  cancerous  nature.  True  cancer  here 
is  exceedingly  rare.  Gross  has  been  unable  to  find  a  single  case  re. 
corded,  but  one  instance  of  the  kind  has  come  to  our  knowledge,  and 
of  that  case  the  minutes  are  in  the  possession  of  Prof.  Parker.] 

The  (Esophagus  appears  as  the  continuation  of  the  phar- 
ynx, it  differs  from  it,  however,  in  structure  ;  the  mucous 
membrane  is  paler,  and  thrown  into  longitudinal  folds  ;  the 
muscular  fibres  are  arranged  in  two  laminse,  the  external 


DU-BLIX    DISSECTOR.  57 

s,Te  longitudinal,  strong  and  red,  attached  superiorly  and 
anteriorly  to  the  criccM  cartilage,  and  below  are  lost  on 
the  stomach;  the  internal  circular  fibres  are  pale,  and 
cease  abrubtly  at  the  cardiac  oriice  of  the  stomach. 

[According  to  some  anatomists,  the  circular  fibres  of  the'  oesophagus 
do  not  terminate  at  this  point,  but  are  collected  into  two  bands,  on« 
of  which  is  situated  at  the  left  of  the  orifice  of  the  stomach,  and  is 
thence  distributed  over  its  anterior  and  posterior  faces,  while  the  other 
f  s  at  the  right  of  the  orifice  and  is  thence  distributed  over  the  ante- 
dor  and  posterior  faces  of  the  greater  cul  de  sac,  if  so  they  must  de- 
•cussate  each  other,  and  form  a  sort  of  sphincter  muscle,  around  the 
orifice.] 

In  the  neck  the  (Esophagus  descends  posterior  to  the  tra- 
chea, and  nearly  in  the  ^middle  line ;  it  inclines  a  little  to  the 
left  side  below,  so  as  to  be  uncovered  by  that  tube  ;  the  left 
lobe  of  the  thyroid  gland,  the  recin  rent  nerve,  and  the  in- 
ferior thyroid  "vessels,  He  on  it  in  this  situation. 

The  morbi?'  appearances  met  vrith  in  the  pharynx  and 
'oesophagus  are  not  very  many  ;  tke  mucous  membrane  of 
the  former  is  liable  to  inflammation,  (cynanche  pkaryngea,) 
and  to  ulceration  from  various  causes ;  the  subnaucous  tis- 
sue is  frequently  the  source  of  polypous  growths,  particu- 
larly at  the  upper  part.  The  lining  membrane  of  the 
oesophagus  is  seldom  the  seat  of  active  inflammation,  ex- 
cept as  the  consequence  of  some  foreign  body,  or  the  con- 
tact of  some  acrid  substance ;  it  is  not  unfrequently  the 
seat  of  stricture,  caused  in  some  cases  by  a  contraction 
and  thickening  of  its  coats,  in  others  by  true  scirrhus, 
ending  in  cancerous  uiceration ;  tumours  in  the  vicinity 
of  this  tube  will  also  interrupt  its  functions,  for  example, 
bronchocele,  charged  bronchial  ganglia,  cr  aneurism  'of 
the  descending  aorta.  The  cesophogus  is  also  sometime? 
affected  with  paralysis,  and  in  hysterical  patients  it  is  very 
subject  to  nervous  affections,  which  frequently  bear  a 
close  resemblance  to  true  stricture  of  this  tube.  The 
course  and  connexions  of  the  oesophagus  in  the  chest  will 
be  seen  hereafter.1'" 

[This  organ  is  the  seat  of  various  congenital  malformations  ;  it 
may  be  double  or  entirely  wanting,  the  pharynx  ending  in  a  blind 
cul-de-sac  :  it  may  terminate  in  a  blind  cul-de-sac  just  below  the 
pharynx  or  near  the  cesophageal  extremity  of  the  stomach  :  it  may 
end  in  the  trachea,  and  it  may  be  preternaturally  dilated  or  contracted. 
Stricture  usually  occurs  a  short  distance  below  the  pharynx,  and  if 
treated  early  with  bougies  may  be  cured,  it  is  sometimes  spasmodic.] 


*  The  student  should  practice  the  passing  of  a  probe  or  canula  armed  with  a 
ligature,  along  the  nares  into  the  pharynx,  and  endeavour  to  enclose  the  uvula  in 
the  noose,  thus  imitating  the  operation  of  tying  polypi  when  situated  in  the  phary- 
nx, on  the  velum,  or  in  the  posterior  nares ;  lit:  may  also  puss  a  flexible  tube  into 


58  DUBLIN    DISSECTOR. 

SECTION  VI. 

DISSECTION    OF    THE    LARYNX. 

The  larynx  is  composed  of  several  cartilages  and 
muscles;  it  is  placed  at  the  anterior  part  of  the  neck, 
between  the  tongue  and  trachea,  and  in  front  of  the  pha- 
rynx and  oesophagus,  it  is  suspended  by  the  muscle  and 
ligaments  from  the  os  hyoides-,  this  bone  is  connected  to 
the  chin  by  several  muscles,  and  to  the  styloid  process  of 
the  temporal  bone  on  each  side  by  the  digastric  and  stylo- 
hyoid  muscle  and  ligament ;  it  consists  of  five  parts,  the 
middle  portion,  or  body,  is  very  rough  and  convex  anterior- 
ly and  superiorly  for  the  attachment  of  muscles,  concave 
posteriorly  and  inferiorly  where  it  covers  the  epiglottide- 
an  gland ;  from  the  body  the  cornua  pass  off,  one  to  either 
side,  giving  attachment  to  muscles  above  and  below,  lined 
by  mucous  membrane,  and  serving  to  expand  the  pharynx 
and  fauces ;  where  each  cornu  joins  the  body,  a  small 
process,  the  appendix,  ascends  obliquely  backwards,  and 
gives  attachment  to  the  stylo-hyoid  ligament  and  muscle. 
Use,  to  serve  as  a  fixed  point  for  the  muscles  of  the  tongue, 
pharynx  and  larynx. 

Four  cartilages  enter  into  the  formation  of  the  skeleton 
of  the  larynx,  the  thyroid,  cricoid  and  two  arytenoid,  and 
one  fibre-cartilage,  the  epiglottis.  The  thyroid  cartilage  is 
placed  at  the  anterior  and  lateral  parts  of  the  larynx ;  it 
presents,  anteriorly,  a  prominence,  named,  in  the  male 
subject,  the  pomum  Adami,  laterally  the  alec,  each  of  which, 
in  passing  backwards,  increases  in  depth,  and  presents  an 
oblique  ridge  for  the  attachment  of  the  sterno-thyroid,  and 
thyreo-hyoid  muscles ;  a  hole  is  frequently  observed  in  each 
ala  near  this  ridge  ;  posteriorly  the  alee  terminate  round 
and  thick,  and  from  their  upper  and  lower  extremities  send 


the  pharynx,  and  thence  direct  it  to  the  stomach  or  into  the  larynx  ;  any  practi- 
tioner may  be  suddenly  called  on  to  use  the  stomach  pump,  in  case  of  poison 
having  been  swallowed,  or  to  inflate  the  lungs  in  asphyxia :  in  theirs*  case,  when 
the  tube  has  passed  into  the  pharynx,  from  the  mouth  or  nares,  the  tongue  should 
be  pressed  back,  so  as  to  close  the  glottis,  and  the  end  of  the  instrument  should 
t»e  kept  close  to  the  vertebrae  to  avoid  irritating  or  pressing  on  the  epiglottis:  in 
the  second  cose,  the  tube  should  be  passed  through  either  naris  into  the  pharynx, 
the  forceps  or  the  finger  of  the  surgeon,  introduced  into  the  mouth,  can  then  guide 
it  downwards  and  forwards  to  the  glottis  ;  at  this  time,  however,  the  tongue  should 
'be  drawn  forwards ;  thus  the  epiglottis  will  be  raised  and  the  glottis  opened  oppo- 
site the  edge  of  the  velum  ;  the  tube  may  then  be  urged  into  the  larynx,  and  arti- 
ficial respiration  commenced.  In  conducting  this  process  it  is  advisable  to  press 
the  upper  part  of  the  trachea  gently  against  the  vertebra;,  so  as  to  fix  the  larynx 
and  the  tube,  as  well  as  to  guard  against  the  admission  of  air  into  the  oesophagus, 
and  the  consequent  inflation  of  the  stomach. 


DUBLIN    DISSECTOR.  59 

off  the  processes  called  cnrnua ;  the  ascending  cornua  are 
connected  to  those  of  the  '»s  hyoides  by  round  ligaments, 
[the  lateral  hyo-thyroid]  which  are  often  cartilaginous,  and 
sometimes  even  bony ;  the  inferior  cornua  are  shorter,  and 
are  attached  by  the  lateral  crico-thyroid  ligaments  to  the 
sides  of  the  cricoid  cartilage  ;  the  anterior  angle  of  the 
thyroid  is  connected  superiorly  to  the  body  of  the  os  hyoi- 
des by  a  thin  membrane,  anterior  hyo-thyroid  ligament,  and 
interiorly  to  the  cricoid  cartilage  by  a  strong  elastic  liga- 
ment, crico-thyroid. — The  cricoid,  or  annular  cartilage,  forms 
the  lower  part  of  the  larynx,  is  narrow  before,  deep  behind ; 
the  inferior  edge  or  circumference  is  nearly  horizontal ; 
the  superior  is  oblique,  leading  from  above  and  from  be- 
hind, downwards  and  forwards- ;  on  its  posterior  surface  is 
a  middle  prominent  ridge,  on  each  side  of  which  is  a  de- 
pression, filled  by  the  posterior  crico-arytenoid  muscle  ;  at 
the  upper  and  back  part  on  each  side  is  a  smooth  articu- 
lating convex  surface,  on  which  each  arytenoid  cartilage 
moves. 

[This  is  a  diarthrodial  articulation,  having  a  small  synovial  mem- 
brane.] 

The  arytenoid  cartilages  are  triangular,  the  base  below 
moving  on  the  cricoid,  the  apex  above  inclining  a  little 
backwards,  and  surmounted  by  a  small  process,  the  appen- 
dix ;  the  internal,  or  opposed  side  of  each  cartilage  is  flat, 
the  external  is  rough  for  the  insertion  of  muscles,  the  pos- 
terior surface  of  each  is  concave,  and  covered  by  the  ary- 
tenoid muscle ;  the  anterior  is  sharp,  and  connected  supe- 
riorly to  the  epiglottis  by  the  aryteno-epiglottidean  folds 
of  mucous  membrane,  which  folds  form  the  sides  of  the 
glottis,  and  inferiorly  to  the  angle  of  the  thyroid  by  two 
ligaments  on  each  side,  called,  thy  reo-aryteno  id,  or  chorda  xo- 
cales  :  these  arise  from  a  sharp  projection  on  the  forepart 
of  the  base  of  each  arytenoid,  pass  forward  converging, 
and  are  inserted  into  the  angle  of  the  thyroid  ;  the  inferior 
is  the  stronger,  it  is  tendinous  and  horizontal,  the  superior 
is  membranous  and  semilunar ;  the  narrow  passage  be- 
tween these  ligaments  of  opposite  sides  is  called  the  rima 
glottidis ;  between  the  superior  and  inferior  ligament  of 
each  side  is  a  scmilunar  fossa  called  the  sinus  or  ventricle 
of  the  larynx. 

The  epiglottis,  or  fibro-cartilage,  is  anterior  to  the  glottis  ; 
it  is  somewhat  of  an  oval  form,  connected  inferiorly  at  its 
origin  by  a  stalk-like  process  to  the  notch  or  angle  of  the 
thyroid  cartilage  ;  anteriorly  by  cellular  membrane  and 
by  the  epiglottidean  gland  to  the  os  hyoides,  also  to  the 
tongue  by  three  folds  of  mucous  membrane,  the  central 


60  DUBLIN    DISSECTOR. 

one  of  which  is  called  the  fr&num  epiglottis  ;  posterior- 
ly to  the  arytenoid  cartilages  by  the  folds  of  mucous  mem- 
brane, which  form  the  sides  of  the  glottis.  The  epiglottis 
stands  nearly  vertical ;  it  is  a  little  curved  forwards  at  its 
upper  border  and  along  its  sides,  so  that  its  anterior  sur- 
face is  concave  from  above  downwards,  and  convex  trans- 
versely ;  and  its  posterior  surface  is  concave  from  side  to- 
side,  and  convex  from  above  downwards  ;  it  is  very  elas- 
tic, and  never  found  ossified,  a  change  which  the  cartilages 
of  the  larynx  are  prone  to  undergo.  In  deglutition  the  epi- 
glottis is  of  much  use  ;  it  covers  the  larynx,  and  so  prevents- 
any  foreign  substance  entering  it :  during  this  act  the 
tongue  is  turned  backwards,,  and  the  larynx  raised  for- 
wards ;  thus  the  glottis  is  closed,  and  the  contents  of  the 
mouth  pass  over  the  epiglottis  into  the  pharynx.  The  la- 
rynx is  lined  by  mucous  membrane,  which  passing  from 
the  tongue  and  pharynx,  covers  the  epiglottis  and  aryte- 
noid cartilages,  forms  their  connecting  folds,  descends  into 
the  larynx,  covers  the  chordae  vacates.,  lines  the  ventricles 
of  the  larynx>,  and  is  continued  down  through  the  trachea 
and  the  branches  of  that  tube  ;  it  is  bu*  loosely  connected 
to  the  cartilages  above  at  the  gk>ttis7  b^t  more  closely  be- 
low ;  several  mucous  glands  are  connected  to  it*  thus  in. 
the  arytene-epiglofc&dean  fold  of  each  sMe  there  are  small 
glands  cal]jed  arytenoid,,  and  in  front  o:!?  the  epiglottis,  be- 
hind the  ©3  hyokles.,  tfee  epiglottifasm  glamd  is  situated  ;  this 
opens  by  sraall'  ducts  on  the  posterior  or  laryngeal  surface 
of  the  epiglottis,  The  openings  of  the  larynx  are  two,  th(y 
superior  or  ihc  glottis?  and  tke  iwj&riw  or  the  rima  glottldis.. 
The  opening  of  t]?_/s  glottis  has  been  already  noticed  ;  it  is-, 
immediately  behkiii  the  tongiie  aad  epiglottis,  and  is  of  i\ 
triangular  form.,  the  base  anteriorly.  (See  page  53.)  The* 
rima  glottidis-  is  thane®  quarters  of  an  inch  below  the  glottic; 
it  is  like  a  slit,  be^ig  very  narrow  frosa  side  to  side,  and  oif 
a  triangular  figure,  the  base  posteriorly  formed  by  the- 
bases  of  the  arytenoid,  and  by  the  upper  and  posterior  edge 
of  the  cricoid  ;  the  apex  is  anteriorly  in  the  angle  of  the 
thyroid  cartilage,  tiie  chorda)  vocales  form  the  sides  :  be- 
low the  rima  glottiiis  the  larynx  enlarges  within  the  cri- 
coid cartilage,  and  is  of  a  circular  figure,  and  soon  termi- 
nates in  the  trachea.  The  muscles  of  the  larynx  are  sym- 
metrical, they  are  found  on  the  front,  sides  and  back  part ; 
those  on  the  forepart  are  the  thyreo-hyoid,  and  the  crico- 
thyrpid  ;  on  each  side  are  the  thyreo  and  lateral  crico-ary- 
tenoid,  and  posteriorly  are  the  arytenoid  and  posterior  cri- 
co-arytenoid. 

THYREO-HYOIDEUS->  broad  and  flat,  arises  from  the  upper 
edge  of  the  oblique  ridge  on  the  ala  of  the  thyroid  carti-. 


DUBLIN    DISSECTOR.  61 

lage,  ascends  a  little  outwards,  and  is  inserted  into  the  lower 
border  of  the  cornu  of  the  os  hyoides.  Use,  to  elevate  and 
draw  forwards  the  larynx  beneath  the  tongue  and  epiglot- 
tis, and  so  cause  the  glottis  to  be  closed  in  deglutition. 
This  muscle  is  partly  covered  by  the  integuments  and  ster- 
no  and  omo-hyoid  ;  it  appears  like  a  continuation  of  the 
sterno-thyroid. 

CRICO-THYROIDEUS,  inferior  to  the  former,  short  and  trian- 
gular ;  arises  narrow  from  the  forepart  of  the  cricoid  carti- 
lage, ascends  obliquely  outwards,  and  is  inserted  broad  into 
the  lower  border  of  the  thyroid.  Use,  to  approximate  these 
cartilages,  and  to  depress  and  draw  forward  the  thyroid, 
also  to  raise  and  draw  backwards  the  cricoid  cartilage,  and 
thus  make  tense  the  chordae  vocales.  The  crico-thyroid 
ligament  occupies  the  space  between  these  muscles  ;  they 
are  covered  by  the  sterno-hyoid.  Raise  the  ala  of  the  thy- 
roid cartilage  on  one  side,  and  the  lateral  muscles  of  the 
larynx  will  be  exposed. 

THYREO-ARYTENOIDEUS  is  flat  and  thin,  arises  from  the  pos- 
terior surface  of  the  thyroid  cartilage  near  its  angle :  the 
fibres  pass  backwards  and  outwards,  expanding  over  the 
side  of  the  rima  glottidis,  and  are  inserted  into  the  anterior 
edge  of  the  arytenoid  cartilage.  Use,  to  draw  the  cartilage 
forward  and  towards  its  fellow,  thereby  diminishing  the 
capacity  of  the  rima  glottidis  ;  these  muscles  can  also  pro- 
duce various  alterations  in  the  form,  position,  and  degree 
of  tension  of  the  chordas  vocales,  which  they  cover,  and 
they  can  compress  the  sinus  or  sacculus  laryngis.  The 
thyreo-arytenoid  muscles  are  considered  by  some  as  the 
principal  and  most  important  agents  in  the  production  of 
voice,  in  consequence  of  their  proximity  to  the  vocal 
chords,  and  their  capability  of  producing  endless  varieties 
in  their  condition,  causing  the  vibration  in  their  edges  so 
to  differ  in  intensity  and  duration,  as  to  produce,  from  the 
air  passing  over  them,  (to  a  certain  extent  only,)  corres- 
ponding varieties  of  sound  or  tone. 

These  muscles  are  covered  by  the  aloe  of  the  thyroid  car- 
tilage ;  they  lie  on  the  chordce  vocales,  and  on  the  inter- 
mediate sinus  ;  superiorly,  their  fibres  extend  to  an  indefi- 
nite height  in  the  mucous  folds  of  the  glottis,  and  inferiorly 
they  are  connected  to  the  following  muscles, 

CRICO-ARYTENOIDEUS  LATERALIS,  arises  from  the  upper 
edge  of  the  side  of  the  cricoid  cartilage,  where  the  latter  is 
covered  by  the  ala  of  the  thyroid  cartilage ;  ascends  ob- 
liquely backwards,  inserted  into  the  base  of  the  arytenoid. 
Use,  to  draw  that  cartilage  forwards  and  outwards,  and 
thus  to  relax  the  vocal  chords,  and  enlarge  the  rima  from 
side  to  side,  but  contract  it  from  before  backwards.  Raise 

6 


62  DUBLIN    DISSECTOR. 

the  mucous  membrane  on  the  back  part  of  the  larynx,  to 
expose  the  muscles  situated  there. 

CRICO-ARYTENOJDEUS  POSTICUS,  strong  and  flat,  arises  from 
the  depression  on  the  posterior  surface  of  the  cricoid ;  the 
fibres  ascend  obliquely  outwards,  inserted  by  a  tendon  into 
the  outside  of  the  base  of  the  arytenoid  cartilage.  Use,  to 
draw  this  cartilage  backwards  and  outwards,  so  as  to  en- 
large the  rima  in  every  direction,  as  in  full  inspiration. 
These  muscles  lie  on  the  back  of  the  cricoid  cartilage,  and 
are  covered  posteriorly  by  the  pale  mucous  membrane  de- 
scending into  the  oesophagus  :  these  and  the  crico-thyroid 
muscles  are  the  dilators  of  the  rima  glottidis. 

ARYTENOIDEUS,  fills  the  interval  between  the  arytenoid 
cartilages,  and  is  enclosed  in  a  fold  of  mucuous  membrane : 
it  consists  of  oblique  and  transverse  fibres ;  the  former  con- 
sist of  two  or  three  fasciculi,  which  pass  from  the  apex  of 
one  cartilage  to  the  base  of  the  opposite ;  the  transverse 
fibres  are  more  numerous,  and  are  attached  to  the  posteri- 
or surface  of  each  cartilage.  Use,  to  approximate  these 
cartilages,  and  close  the  sides  of  the  rima :  these,  together 
with  the  thyreoand  crico-ary  tenoidei  laterales  are  the  con- 
tractors of  the  rima  glottis.  In  the  aryteno-epiglottidean 
folds,  fleshy  fibres  are  sometimes  discernible,  and  have 
been  described  as  distinct  muscles,  and  named  from  their 
situation,  aryteno-epiglottidean  and  thyreo-epiglottidean  or  the 
depressors  of  the  epiglottis.  In  the  human  subject,  how- 
ever, these  are  never  sufficiently  well  marked  to  merit  the 
apellation  of  distinct  muscles. 

The  arteries  which  supply  the  larynx  are  derived  from 
the  superior  and  inferior  thyroid  ;  the  former  is  a  branch 
of  the  external  carotid,  the  latter  of  the  subclavian.  The 
laryngeal  nerves  are  four  in  number,  two  on  each  side,  the 
superior  and  inferior ;  both  are  derived  from  the  par  vagum 
or  pneumo-gastric ;  the  former  arising  from  it  near  the 
base  of  the  cranium,  the  latter,  on  the  right  side,  comes  off 
from  this  trunk  at  the  lower  part  of  the  neck,  and  on  the 
left  side  it  arises  from  it  in  the  thorax,  below  the  arch  of 
the  aorta:  the  inferior  laryngeal  nerves  are  principally 
distributed  to  the  muscles,  and  the  superior  to  the  mem- 
brane and  glands  of  the  larynx,  but  not  exclusively  so. 
The  inferior  supplies  the  posterior  and  lateral  crico-ary- 
tenoid  andthe  thyrco-arytenoid  muscles  ;  the  superior  sends 
a  large  branch  to  the  arytenoid,  and  a  small,  but  very  long 
filament  to  the  crico-thyroid  muscle ;  several  branches  of 
this  nerve  are  distributed  to  the  epiglottis  and  to  the  mucous 
membrane  at  the  glottis,  which  in  this  situation  possesses 
great  sensibility.  From  this  view  it  would  appear  that  the 
inferior  laryngeal  nerve  supplies  the  dilating  muscles  of 


DUBLIN    DISSECTOR.  63 

the  larynx  which  are  the  principle  agents  in  voice,  while 
the  superior  supplies  those  which  close  the  glottis,  as  also 
the  lining  membrane,  which  possesses  very  peculiar  and 
very  delicate  sensibility.  [For  the  anatomy  of  the  trachea, 
see  p.  93.] 

The  larynx  and  trachea  are  subject  to  many  morbid 
changes  of  which  the  mucuous  membrane  is  most  com- 
monly the  seat ;  inflammation  of  that  lining  the  larynx  is 
named  cynanche  laryngea,  or  laryngitis,  of  that  lining  the 
trachea,  cynanche  trachealis,  or  croup  ;  in  the  latter  case 
an  exudation  of  lymph,  or  a  false  membrane  is  usually 
formed  in  the  trachea.,  in  the  former  case,  effusion  of  serum 
in  the  loose  submucous  tissue,  or  oedema  of  the  glottis,  is 
a  frequent  and  often  fatal  effect ;  ulceration,  the  effect  of 
inflammation,  is  not  uncommon  about  the  glottis:  syphilis 
and  phthisis  also  occasionally  induce  ulceration  in  this 
part,  and  even  involve  the  epiglottis  and  the  arytenoid  car- 
tilages. 

[In  ulceration  of  the  cartilages,  large  pieces  are  sometimes  thrown 
off,  but  these  organs  are  more  prone  to  ossification,  particularly  in  ad- 
vanced life  :  the  thyriod  and  cricoid  cartilages,  are  most  commonly 
affected  and  it  is  said  that  no  cases  of  ossification  of  the  arytenoids. 
or  epiglottis  have  been  recorded.  There  is  however  in  the  college 
museum  a  specimen  of  very  complete  ossification,  of  the  thyroid 
cricoid,  and  both  arytenoid  cartilages.  Polypes  are  sometimes  found 
within  the  larynx.  The  muscles  of  the  larynx  are  also  sometimes 
•diseased,  either  being  infiltrated  with  tuberculous  matter,  or  else  being 
in  a  state  of  atrophy,  hence  causing  alterations  in  the  voice :  foreign 
bodies  may  from  their  size  be  arrested  in  the  calibre  of  the  larynx,  or 
if  small  they  may  be  lodged  in  its  sinuses  ;  the  term  bronchotomy  as 
applied  to  operations  upon  the  larynx  or  trachea,  is  manifestly  im- 
proper, there  being  in  fact  no  such  operation  as  bronchotomy,  which 
implies  a  section  of  the  bronchial  tubes,  and  they  are  beyond  the 
reach  of  the  surgeon.] 

Foreign  bodies  impacted  in  the  lower  part  of  the  phar- 
ynx, or  when  engaged  in  the  larynx,  or  when  fallen  into 
the  trachea,  may  cause  such  suspension  of  respiration  as 
to  call  for  the  operation  of  bronchotomy ;  suspended  ani- 
mation, also,  from  any  cause,  or  any  tumour  in  the  fauces 
which  impedes  respiration,  may  require  the  same  means ; 
this  operation  is  two-fold,  laryngotomy  and  tracheotomy ; 
in  the  first  the  air  tube  is  to  be  opened  through  the  crico- 
thyroid  ligament,  in  the  second  through  the  fourth,  fifth, 
and  sixth  rings  of  the  trachea. 


64  DUBLIN    DISSECTOR, 

SECTION  VII. 

DISSECTION    OF    THE    DEEP    MUSCLES    OF    THE    NECK. 

THESE  muscles,  which  are  seven  in  number  on  each  side, 
form  the  third  layer  of  the  cervical  muscles ;  they  lie  close 
to  the  vertebrae,  and  are  exposed  by  removing  the  pharynx, 
larynx,  cervical  vessels  and  nerves. 

LONGUS  COLLI  extends  from  the  third  dorsal  vertebra  to 
the  atlas ;  it  arises  from  the  sides  of  the  bodies  of  the  three 
superior  dorsal  and  four  inferior  cervical  vertebrae,  from 
the  inter  vertebral  ligaments,  also  from  the  head  of  the  first 
rib,  and  from  the  anterior  tubercles  of  the  transverse  pro- 
cesses of  the  four  last  cervical  vertebrae  ;  the  fibres  ascend 
obliquely  inwards,  adhering  to  each  bone  in  their  course, 
and  are  inserted  into  the  forepart  of  the  first,  second,  and 
third  cervical  vertebrae.  Use,  to  bend  the  neck  to  one  side, 
and  rotate  the  atlas  on  the  dentata  ;  or,  if  both  muscles 
act,  to  bend  the  neck  directly  forwards.  This  muscle  ap- 
pears to  consist  of  an  inferior  and  superior  portion ;  the 
first  arising  from  the  bodies  of  the  dorsal  is  inserted  into 
those  of  the  inferior  cervical  vertebrae  ;  the  second  arising 
from  the  transverse  processes  of  the  third,  fourth,  and  fifth 
cervical  vertebra?,  is  inserted  into  the  bodies  of  the  first 
and  second.  These  muscles,  like  most  of  those  which  ad- 
here to  the  vertebrae,  though  long,  yet  consist  of  short 
fibres  which  pass  from  one  bone  to  another,  are  generally 
intermixed  with  tendinous  substance,  and  are  irregular  as 
to  the  number  of  the  vertebrae  to  which  they  are  attached. 

RECTUS  CAPITIS  ANTICUS  MAJOR,  long  and  flat,  arises  by 
small  tendons  from  the  anterior  tubercles  of  the  transverse 
processes  of  the  four  last  cervical  vertebrae ;  they  soon 
unite  in  a  fleshy  substance  which  ascends  obliquely  in- 
wards, and  is  inserted  broad  into  the  cuneiform  process  of 
the  occipital  bone.  Use,  to  bend  forwards  the  neck  and 
head.  This  muscle  lies  behind  the  carotid  artery  and  sym- 
pathetic nerve,  and  between  the  longus  colli  and  scaleni. 
Separate  this  muscle  from  its  insertion,  and  we  expose  the 
following : 

RECTUS  CAPITIS  ANTICUS  MINOR,  short  and  narrow,  arises 
from  the  transverse  process  of  the  atlas,  ascends  inwards, 
and  is  inserted  into  the  cuneiform  process.  Use,  to  bend  the 
head  forwards  and  to  one  side  on  the  atlas :  this  muscle 
lies  to  the  outer  side,  but  is  in  part  concealed  by  the  last. 

RECTUS  CAPITIS  LATERALIS,  very  short,  arises  from  the 
transverse  process  of  the  atlas,  ascends,  and  is  inserted  into 


DUBLIN    DISSECTOR.  65 

the  semilunar  ridge  or  jugular  process  of  the  occipital 
bone,  which  extends  from  the  condyle  to  the  mastoid  pro- 
cess. Use,  with  the  last  muscle  it  can  bend  the  head  for- 
wards or  incline  it  to  one  side.  This  muscle  is  external  to 
that  last  described ;  it  lies  on  the  vertebral  artery,  and  is 
covered  by  the  jugular  vein. 

SCALEJSUS  ANTICUS,  arises  tendinous  from  the  anterior 
tubercles  of  the  transverse  processes  of  the  third,  fourth, 
fifth,  and  sixth  cervical  vertebrae ;  the  fibres  descend  ob- 
liquely forwards  and  outwards,  form  a  flat  muscle,  which 
is  inserted  tendinous  into  the  upper  surface  of  the  first  rib, 
near  its  cartilage.  Use,  to  bend  the  neck  forwards  and 
laterally,  also  to  elevate  and  fix  the  rib  as  in  inspiration. 
The  phrenic  nerve  descends  on  the  anterior  surface  of  this 
muscle ;  the  subclavian  vein  crosses  its  insertion ;  the 
omo-hyoid  and  sterno-mastoid  lie  anterior  to  it ;  the  sub- 
clavian artery  and  brachial  plexus  are  behind  it,  and  the 
vertebral  vessels  separates  it  from  the  longus  colli. 

SCALENUS  MEDIUS,  arises  from  the  posterior  tubercles  of 
the  transverse  processes  of  four  or  five  inferior  cervical 
vertebrae,  by  small  tendinous  fibres ;  these  become  fleshy, 
and  descend  obliquely  outwards  and  backwards,  and  are 
inserted  into  the  upper  surface  of  the  second  rib  behind  the 
subclavian  artery.  Use,  similar  to  the  last.  This  muscle 
is  covered  by  the  brachial  plexus,  subclavian  artery,  and 
anterior  scalenus. 

SCALENUS  POSTICUS,  arises  from  the  posterior  tubercles  of 
two  or  three  lower  cervical  vertebrae,  descends  behind  the 
former,  and  is  inserted  into  the  upper  edge  of  the  second 
rib,  between  its  tubercle  and  angle.  Use,  to  elevate  the 
second  rib,  to  bend  the  neck  to  one  side,  and  a  little  back- 
wards. One  or  two  branches  of  the  brachial  plexus  some- 
times separate  this  from  the  middle  scalenus,  at  other  times 
there  is  no  distinction  between  them,  excepting  in  their  in- 
sertion :  behind  the  posterior  scalenus  lie  the  transversalis 
and  splemus  colli,  also  the  levator  anguli  scapulas,  which 
muscles  cannot  be  examined  at  present 

[Varieties.  The  fasciculi  of  the  scaleni  muscles,  are  variable,  and 
are  more  or  less  run  together,  so  that  the  number  described  varies 
with  different  anatomists,  from  Chaussier,  who  describes  but  one,  to 
Albinus  who  makes  five.] 

We  shall  next  proceed  to  the  dissection  of  the  thorax. 
6* 


66  DUBLIN    DISSECTO> 

CHAPTER   III. 

DISSECTION  OF  THE  THORAX. 
SECTION  I. 

OF  THE  MUSCLES  ON  THE  ANTERIOR  AND  LATERAL 
PARTS  OF  THE  THORAX. 

MAKE  one  incision  through  the  integuments  along  the 
clavicle,  a  second  from  the  upper  end  of  the  sternum  tc 
the  ensiform  cartilage,  and  from  this  point  carry  a  third 
towards  the  shoulder ;  reflect  the  integuments  and  subja- 
cent cellular  membrane  from  within  and  from  below,  up- 
wards and  outwards,  and  thus  the  great  pectoral  muscle 
will  be  exposed,  the  dissection  of  which  will  be  facilitated 
if  its  fibres  be  made  tense  by  separating  the  arm  from  the 
side.*  Beneath  the  integuments  in  the  female  we  find  the 
mammary  gland ;  this  is  a  conglomerate  gland,  imbedded  in 
fat,  hemispherical,  flat  posteriorly,  convex  anteriorly,  sur- 
rounded by  a  capsule  of  condensed  cellular  membrane, 
which  is  loosely  connected  to  the  pectoral  muscle,  and 
sends  processes  into  the  gland  to  support  and  connect  its 
several  lobules ;  these  last  are  very  soft  and  pale,  almost 
white ;  from  each  of  them  small  ducts  arise,  which  uniting 
together  form  larger  tubes ;  these  converge  towards  the 
root  of  the  nipple,  where  they  expand  into  sinuses,  from 
which  smaller  ducts  proceed  and  open  on  its  surface  :  the 
skin  covering  the  breast  is  soft  and  delicate,  and  about  the 
centre  of  it,  is  the  conical  projection  called  the  nipple,  near 
the  point  of  which  the  lactiferous  ducts  open  ;  the  base  is 
surrounded  by  an  areola  of  a  dark  colour.  This  gland 
will  be  found  to  differ  in  structure  in  different  subjects  ;  in 
some  the  capsule  is  indistinct,  and  the  lobules  scattered,  or 
more  separate  than  usual ;  in  some  it  has  a  redder  appear- 
ance than  in  others,  and  it  frequently  feels  unusually  hard 
or  rugged,  although  free  from  disease. 

[This  gland  is  of  a  light  pink  color ;  it  is  difficult  to  lay  down  any 
rule,  as  to  its  volume,  for  it  is  very  small,  up  to  the  age  of  puberty, 
when  it  rapidly  increases  in  development, and  it  reaches  its  maximum 

*The  student  of  some  experience,  instead  of  removing  the  skin  from  this  region, 
according  to  the  above  directions,  may  rather  practise  the  operation  of  extirpation  of 
the  breast,  which  can  be  easily  accomplished  by  two  seimelliptical  incisions,  one 
below,  and  the  other  above  the  gland,  through  the  integuments  and  nearly  parallel 
to  the  fibres  of  the  great  pectoral  muscle,  from  which  the  gland  can  be  then  easily 
detached,  unless  disease  should  have  caused  any  very  close  adhesion. 


DUBLIN    DISSECTOR.  67 

during  gestation  and  lactation,  and  again  after  the  period  of  child 
bearing  is  past,  it  becomes  atrophied,  and  even  confounded  with  the 
surrounding  cellular  tissue  ;  if  separated  entirely  from  the  adjoining 
cellular  and  adipose  tissue  and  placed  upon  a  flat  surface,  it  is  found 
to  be  of  a  circular  form  having  a  diameter  of  from  three  to  five  inches, 
and  a  thickness  of  from  ten  to  fifteen  lines.  It  is  said  that  the  left 
mamma  is  usually  somewhat  larger  than  the  right.  These  organs  in 
connexion  with  their  functions  constitute  the  characteristic  of  one  of 
the  zoological  classes  of  animals,  the  mammalia. 

The  organs  exist  in  the  male  subject  though  not  usually  developed, 
except  in  some  rare  instances  in  which  they  have  afforded  an  abun- 
dant secretion  of  milk. 

On  the  surface  of  the  areola,  there  are  a  number  of  small  tubercles 
surrounding  the  nipple,  which  are  particularly  prominent  in  pregnant, 
and  nursing  females,  it  has  been  supposed  that  these  bodies  secreted 
an  oleaginous  substance,  to  protect  the  nipple,  and  guard  it  against 
excoriation,  while  nursing,  but  there  are  several  circumstances  which 
go  to  prove  that  they  are  of  the  same  structure  as  the  mamma,  itself, 
and  that  they  secrete  milk.  The  mammas  arevery  abundantly  supplied 
with  blood,  by  the  external  thoracic,  intercostal,  and  internal  mam- 
mary arteries  also  with  nerves  from  the  intercostals  and  axillary 
plexus.] 

The  female  breast  is  the  seat  of  many  morbid  changes, 
viz.  inflammation,  and  suppuration,  either  in  the  body  of 
the  gland,  or  in  the  cellular  tissue  around  it  or  behind  it, 
that  is  between  it  and  the  muscle — enlargement — atrophy 
— tumours  of  various  kinds,  adipose,  hydatid,  cartilaginous, 
scirrhus,  cancerous,  &c. ;  some  indolent,  chronic,  andinnoc- 
cuous,  others  more  rapid  in  their  progress,  fungoid,  and 
malignant. 

[Hypertrophy  of  the  breast,  sometimes  occurs  in  the  male,  and  in 
the  female  it  occasionally  acquires  an  enormous  magnitude  ;  cases 
being  recorded,  in  which  it  weighed  fifteen,  twenty,  and  even  sixty 
four  pounds.  Encephaloid  disease  and  calcareous  formations,  and 
neuralgia  also  occur  ;  apoplexy  of  the  breast  is  an  affection  peculiar 
to  young  girls,  coming  on  just  before  the  establishment  of  the  men- 
strual secretion  and  disappearing  soon  after.  Carcinoma  sometimes 
occurs  in  the  male  breast ;  in  male  infants  a  few  days  old,  the  breasts 
sometimes  become  swelled,  red,  and  painful,  and  by  gentle  pressure  a 
fluid  resembling  milk  is  forced  out.  Additional  nipples  are  not  un- 
common, and  occasionally  a  supernumerary  mamma  exists,  a  case  is 
recorded  in  which  the  additional  organ  occupied  the  left  groin,  and 
secreted  milk  freely.] 

PECTORALIS  MAJOR,  flat  and  triangular,  arises  somewhat 
tendinous  from  the  sternal  half  of  the  clavicle,  from  the 
anterior  surface  of  the  sternum,  fleshy  from  the  cartilages 
of  the  third,  fourth,  fifth,  and  sixth  true  ribs,  and  from  an 
aponeurosis  common  to  it  and  the  external  oblique  muscle ; 
the  clavicular  fibres  descend,  the  sternal  pass  horizontally, 
and  the  costal  ascend  obliquely  ;  all  pass  outwards  in  front 


68  DUBLIN    DISSECTOR. 

of  the  axilla  towards  the  humerus,  into  which  they  are 
inserted  by  a  flat  tendon  into  the  anterior  edge  of  the  bici- 
pital  groove,  and  by  an  aponeurosis  into  the  fascia  of  the 
arm  ;  a  line  of  cellular  membrane  separates  the  clavicular 
from  the  sternal  portion ;  in  some  cases  these  appear  as 
distinct  muscles.  Use,  the  clavicular  portion  can  raise  the 
arm  and  draw  it  forward,  the  sternal  can  press  it  to  the  side, 
particularly  if  assisted  by  the  latissimus  dorsi,  and  the 
costal  portion  can  draw  it  downwards  and  forwards  :  the 
whole  muscle  will  draw  the  arm  forwards  and  inwards  on 
the  chest :  if  the  arm  have  been  rotated  outwards,  it  can 
roll  it  inwards,  and  so  pronate  the  hand ;  if  the  arms  be 
fixed,  and  this  pair  of  muscles  act,  they  will  draw  the  ribs 
upwards  and  outwards,  and  thus  by  enlarging  the  thorax 
assist  in  inspiration.  This  muscle  is  covered  by  the  skin, 
platysma  and  mammary  gland,  and  its  insertion  is  partly 
concealed  by  the  deltoid ;  it  covers  a  portion  of  the  ster- 
num and  of  the  true  ribs,  also  the  subclavian  and  lesser 
pectoral  muscles,  the  coraco-clavicular  ligament,  the  tho- 
racic and  axillary  vessels  and  nerves.  Between  the  clavi- 
cular portion  of  "this  muscle,  and  the  anterior  edge  of  the 
deltoid,  is  a  space  filled  by  cellular  tissue,  the  cephalic 
vein  and  a  small  artery,  [a  branch  of  the  thoracica  acro- 
mial.]  The  tendinous  fibres  of  the  sternal  portions  of  op- 
posite sides  decussate  each  other,  and  cover  the  sternum 
with  a  sort  of  aponeurosis ;  the  insertion  has  a  twisted 
appearance  in  front  of  the  axilla,  the  sternal  and  costal 
portions  being  folded  behind  the  clavicular,  and  inserted 
superior  and  posterior  to  it  into  the  anterior  edge  of  the 
bicipital  groove,  while  the  clavicular  is  united  to  the  del- 
toid, and  is  inserted  into  the  humerus  along  with  that  mus- 
cle ;  in  some  subjects  a  bursa  may  be  found  between  these 
two  insertions  of  the  pectoral  muscle.  From  the  lower 
edge  of  the  costal  portion  a  fleshy  slip  sometimes  descends 
and  joins  either  the  rectus  or  external  oblique  muscle  of 
the  abdomen ;  and  in  some  a  strong  muscular  band  con- 
nects it  to  the  inferior  margin  of  the  latissimus  dorsi. 

[Other  varieties.  Sometimes  this  muscle  is  attached  by  a  fasci- 
culus to  the  brachialis  internus,  sometimes  a  fasciculus  comes  off 
towards  the  axilla,  is  converted  into  a  tendon,  and  finally  inserted 
into  the  internal  tuberosity  of  the  os  humeri ;  sometimes  a  fasciculus 
comes  off  from  its  tendon,  crosses  its  insertion,  and  the  bicipital  groove 
of  the  os  brachii,  and  is  blended  with  the  tendon  of  the  supra  spinatus.] 

Make  a  perpendicular  division  of  this  muscle,  reflect 
the  edges,  one  towards  the  sternum,  the  other  towards  the 
shoulder ;  and  the  lesser  pectoral  and  subclavian  muscles 
come  into  view. 

PECTOEALIS  MINOR,  flat  and  triangular,  arises  from  the 


DUBLIN    DISSECTOR.  69 

external  surface  and  upper  edge  of  the  third,  fourth,  and 
fifth  ribs,  sometimes  from  the  second,  external  to  their  car- 
tilages ;  the  fibres  ascend,  obliquely  outwards  and  back- 
wards, and  converging,  end  in  a  flat  tendon,  which  is  in- 
serted into  the  inner  and  upper  surface  of  the  coracoid 
process,  near  its  anterior  extremity,  being  here  connected 
with  the  coraco-brachialis  and  short-head  of  the  biceps ; 
a  band  of  this  tendon  frequently  passes  over  this  process 
through  the  triangular  ligament,  and  is  connected  to  it,  or 
to  the  tendon  of  the  supra-spinatus,  or  to  the  capsular  li- 
gament of  the  shoulder.  Use,  to  draw  the  shoulder  for- 
wards, downwards,  and  inwards,  also  to  assist  the  great 
pectoral  in  elevating  the  ribs  in  inspiration.  This  mus- 
cle is  covered  by  the  great  pectoral,  and  partly  at  its 
insertion  by  the  margin  of  the  deltoid  muscle,  a  few  of  its 
inferior  fibres  are  covered  only  by  the  skin  ;  it  lies  ante- 
rior to  the  serratus  magnus,  axillary  vessels  and  nerves. 

[Varieties.  A  third  pectoral  muscle,  sometimes  lies  below  this, 
arising  from  the  first  and  second  ribs,  and  inserted  into  the  coracoid 
process.  Sometimes  a  fasciculus  arises  from  the  first  rib  and  passing 
beneath  the  lesser  pectoral  is  inserted  into  the  capsular  ligament  of 
the  shoulder  joint ;  it  is  sometimes  connected  with  the  tendon  of  the 
coraco-brachial  by  a  fleshy  slip.] 

SUECLAVIUS,  small  and  round,  arises  by  a  flat  tendon  from 
the  cartilage  of  the  first  rib,  external  to  the  rhomboid  or 
costo-clavicular  ligament,  soon  becomes  fleshy,  and  as- 
cending outwards  and  backwards,  is  inserted  into  the  ex- 
ternal half  of  the  inferior  surface  of  the  clavicle,  extend- 
ing as  far  outwards  as  the  space  between  the  conoid  and 
trapezoid  ligaments.  Use,  to  draw  the  clavicle  and  shoul- 
der forwards  and  downwards,  also  to  elevate  the  first  rib 
in  inspiration,  if  the  shoulder  and  clavicle  be  raised  and 
fixed.  This  muscle  is  covered  by  the  clavicle  and  great 
pectoral ;  it  lies  anterior  to  the  axillary  vessels  and  nerves, 
which  separate  it  from  the  first  rib  ;  it  is  covered  by  a 
thin  but  strong  aponeurosis,  which  is  attached  to  the  car- 
tilage of  the  rib,  and  to  the  clavicle  and  subclavian  mus- 
cle, from  which  it  passes  downwards  and  outwards  to  the 
coracoid  process,  arching  across  the  great  vessels,  and  is 
then  connected  to  that  process,  and  to  the  tendon  of  the 
lesser  pectoral ;  this  fascia  is  called  by  some  the  coraco- 
davicular  ligament,  by  others  the  costo-coracoid ;  it  is  some- 
times very  strong,  and  from  the  manner  in  which  it  is  ex- 
tended over  the  vessels,  it  renders  it  difficult  to  feel  the 
pulsation  of  the  axillary  artery  below  the  clavicle. 

[Variety.     This  muscle  is  sometimes  double.] 

SERRATUS  MAGNUS,  thin  and  broad,  particularly  anterior- 


70  DUBLIN    DISSECTOR. 

ly,  placed  behind  the  pectoral  muscles  and  the  axillary 
vessels,  and  between  the  scapula  and  the  ribs,  arises  by 
eight  or  nine  fleshy  slips,  from  the  eight  or  nine  superior 
ribs ;  the  fibres  ascend  obliquely  backwards,  and  are  in- 
serted between  the  subscapular,  the  rhomboid  and  levator 
anguli  muscles  into  the  base  of  the  scapula,  but  particu- 
larly into  the  superior  and  inferior  angles.  Use,  to  draw 
the  scapula  forwards,  particularly  the  inferior  angle,  and 
thus,  by  rotating  this  bone  on  its" axis,  to  raise  the  acromi- 
on  process  and  the  shoulder  joint ;  when  the  upper  ex- 
tremity is  fixed,  this  muscle  can  raise  and  draw  outwards 
the  ribs,  so  as  to  assist  in  inspiration. — The  serratus  mag- 
nus  lies  on  the  ribs  and  intercostal  muscles ;  also  on  a 
portion  of  the  serratus  posticus  ;  external  to  it  are  the  ax- 
illary vessels,  the  scapula  and  subscapular  muscle;  the 
trapezius,  latissimus  dorsi  and  rhomboid  muscles  lie  be- 
hind it,  and  the  pectoral  muscles  are  anterior  to  it;  an 
abundance  of  loose  cellular  membrane  connected  to  its 
surface  allows  it  to  glide  on  the  ribs,  and  also  facilitates 
the  movements  of  the  scapula  upon  it.  The  four  superior 
digitations  lie  behind  those  of  the  lesser  pectoral,  and  the 
four  inferior,  which  are  only  covered  by  the  skin,  indigi- 
tate  with  the  origins  of  the  external  oblique.  If  the  clavi- 
cle be  separated  from  the  sternum,  and  the  scapula  pulled 
from  the  side,  this  muscle  will  then  become  tense,  and  in 
this  state  it  appears  to  consist  of  three  portions,  which 
diifer  in  structure  and  in  form :  the  superior  is  a  thick, 
short  and  strong  fasciculus,  somewhat  square,  passing  from 
the  two  first  ribs  beneath  the  axillary  vessels  and  brachi- 
al  plexus,  to  the  superior  angle  of  the  scapula ;  its  flat 
surface  is  directed  upwards,  and  lies  on  a  plane  anterior 
to  the  next  or  middle  division,  which  is  very  thin,  consist- 
ing of  but  few  fleshy  fibres,  connected  together  by  an 
aponeurosis.  This  portion  is  of  a  triangular  form,  the 
apex  attached  to  the  third  and  fourth  ribs,  the  base  to  the 
basis  of  the  scapula,  not  exactly  to  the  bone,  but  to  a 
strong  tendinous  cord,  which  extends  along  this  line  from 
the  superior  to  the  inferior  angle.  The  third,  or  inferior 
division  of  the  serratus  is  the  strongest  and  most  exten- 
sive; it  is  radiated  or  triangular:  the  apex  thick  and 
fleshy,  attached  to  the  inferior  angle  of  the  scapula  ;  the 
base  thin  and  expanded  on  the  ribs.  The  serratus  may  be 
again  examined  when  dissecting  the  muscle  on  the  back  of 
the  trunk. 

[Variety.     This  muscle  has  sometimes  ten  or  eleven  origins.] 

INTEKCOSTALES,  are  twenty -two  in  number  on  each  side, 
eleven  external   and  eleven   internal; — the  external  com- 


DUBLIN    DISSECTOR.  71 

mence  at  the  transverse  processes  of  the  dorsal  vertebrae, 
arise  from  the  inferior  edge  of  each  rib,  descend  in  fasci- 
culi obliquely  forwards,  and  are  inserted  into  the  external 
lip  of  the  superior  edge  of  the  rib  beneath,  and  terminate 
a  little  behind  the  costal  extremity  of  the  cartilages ;  an 
aponeurosis,  the  fibres  of  which  run  in  the  same  direction, 
supply  their  place  as  far  as  the  sternum.  The  internal 
intercostal  muscles  take  an  opposite  direction,  and  decussate 
the  former :  they  commence  at  the  sternum,  and  are  dis- 
continued at  the  angles  of  the  ribs ;  they  arise  from  the 
inner  lip  of  the  lower  edge  of  each  cartilage  and  rib,  the 
fibres,  paler  and  shorter  than  those  of  the  external,  de- 
scend obliquely  backwards,  and  are  inserted  into  the  inner 
lip  of  the  superior  edge  of  the  cartilage  and  rib  beneath. 
Use,  both  laminae  co-operate  to  raise  the  ribs,  the  first  rib 
being  fixed  by  the  scaleni.  The  intercostal  muscles,  in 
elevating  the  ribs,  also  evert  their  lower  edges,  and  twist 
them  at  their  vertebral  and  sternal  ends,  and  thus  assist  in 
inspiration  by  enlarging  the  chest  transversely,  and  from 
before  backwards.  The  internal  layer  lies  on  the  pleura, 
and  is  separated  from  the  external  by  the  intercostal  ves- 
sels and  nerves ;  the  external  layer  is  connected  to  the 
pleura  only  in  the  space  between  the  angles  of  the  ribs  and 
the  vertebrae.  At  the  posterior  extremity  of  the  external 
intercostal  muscles  there  are  the  following  twelve  small 
muscles,  which,  however,  may  be  seen  more  fully  when 
the  muscles  of  the  back  have  been  dissected. 

LEVATORES  COSTARTJM,  arise  narrow  and  tendinous  from 
the  extremity  of  each  dorsal  transverse  process,  descend 
obliquely  outwards,  and  are  inserted  broad  into  the  upper 
edge  of  the  rib  beneath,  between  its  tubercle  and  angle ; 
their  name  denotes  their  use.  They  are  parallel  to,  and 
frequently  appear  as  a  portion  of  the  external  intercostals  ; 
the  first  levator  is  short,  and  arises  from  the  last  cervical 
vertebra ;  the  inferior  increase  in  length  and  size. 

Behind  the  sternum  are  a  pair  of  small  muscles,  triangu- 
lares  sterni,  which  cannot  be  seen  until  this  bone  is  re- 
moved ;  we  describe  them  now,  although  their  dissection 
may  be  postponed  until  the  cavity  of  the  thorax  has  been 
opened. 

TRIANGULARIS  STERNI,  or  STERNO-COSTALIS,  arises  from  the 
posterior  surface  and  edge  of  the  lower  part  of  the  ster- 
num, and  from  the  xiphoid  cartilage ;  the  fibres  ascend  ob- 
liquely outwards,  the  inferior  pass  transversely — inserted 
into  the  cartilages  of  the  fourth,  fifth,  and  sixth  ribs.  Use, 
to  depress  and  draw  backwards  the  cartilages  of  the  ribs, 
so  as  to  assist  in  expiration.  These  muscles  lie  on  the 
pleurae,  pericardium,  and  diaphragm,  are  covered  by  the 


72  DUBLIN    DISSECTOR. 

sternum,  cartilages  of  the  ribs,  and  mammary  vessels. 
They  antagonize  the  external  intercostals,  to  whose  fibres, 
however,  they  are  parallel,  but  they  arise  from  the  more 
fixed,  and  are  inserted  into  the  more  moveable  part  of  the 
cartilage,  and  this  also  explains  the  cause  of  the  external 
intercostals  terminating  at  the  ends  of  the  ribs,  and  not  con- 
tinuing as  far  forwards  as  the  sternum.  The  mechanism 
of  respiration  shall  be  further  considered  when  the  dia- 
phram  has  been  examined,  (see  dissection  of  it.)  In  con- 
nexion with  the  muscles  of  the  thorax,  the  student  should 
study  the  anatomy  of  the  axilla. 


SECTION  II. 


DISSECTION    OF    THE    AXILLA. 

The  Axilla  is  a  conical  cavity,  the  apex  superiorly  at  the 
coracoid  process  and  clavicle,  the  base  below,  between  the 
pectoralis  major,  and  the  latissimus  dorsi  muscles,  and 
formed  by  the  skin  and  a  thick  fascia ;  it  is  bounded  an- 
teriorly by  the  great  and  lesser  pectoral  muscles,  internal- 
ly by  the  serratus  magnus  and  the  ribs,  externally  by  the 
scapula,  subscapular  muscle,  and  the  upper  part  of  the  hu- 
merus,  and  posteriorly  by  the  serratus,  latissimus  dorsi, 
and  teres  major  muscles.  This  region  contains  several 
lymphatic  ganglia,  vessels  and  nerves,  and  a  quantity  of 
loose  cellular  and  adipose  tissue,  which  is  continued  from 
the  neck  beneath  the  clavicle,  and  often  presents  a  watery 
reddish  appearance.  When  the  pectoral  muscles  have 
been  divided,  and  some  cellular  membrane  removed,  the 
axillary  vein  first  appears  ;  at  the  upper  part  of  the  axilla, 
this  vessel  is  internal  and  anterior  to  the  artery  ;  inferior- 
ly  it  is  directly  over  this  vessel,  and  more  closely  connect- 
ed to  it  than  above ;  this  vein  receives  the  cephalic  vein, 
and  several  branches  from  the  parietes  of  the  thorax,  and 
from  the  shoulder.  The  axillary  artery  may  be  next  seen, 
taking  an  oblique  course  downwards  and  outwards  through 
this  space,  and  giving  off  thoracic  branches  from  its  inter- 
nal side  ;  and  from  its  external,  the  subscapular  and  cir- 
cumflex arteries ;  behind  the  artery,  at  the  upper  part  of 
the  axilla,  the  brachial  plexus  of  nerves  is  seen ;  as  this  de- 
scends it  becomes  more  and  more  closely  connected  to  it, 
and  at  the  lower  part  of  this  cavity,  the  branches  of  the 
plexus  have  almost  surrounded  the  artery.  This  plexus 


DUBLIN    DISSECTOR.  73 

rnay  be  seen  dividing  into  several  branches ;  superiorly,  it 
gives  oft'  the  thoracic,  supra,  and  subscapular  ;  and  lower 
down  it  divides  into  the  external  and  internal  cutaneous, 
the  median,  ulnar,  radial,  or  spiral,  and  articular  or  cir- 
cumflex. The  general  distribution  of  these  branches  will 
be  noticed  in  the  dissection  of  the  upper  extremity,  and  for 
their  particular  description,  see  Anatomy  of  the  Nervous 
System.  At  the  lower  part  of  the  axilla,  the  artery  may 
be  observed  in  general  to  lie  between  the  two  roots  of  the 
median  nerve,  with  the  external  cutaneous  to  its  outer  or 
humeral  side,  and  with  the  ulnar  and  internal  cutaneous 
to  its  inner  or  thoracic  side,  while  posterior  to  it  are  the 
musculo-spiral  and  articular  nerves.  The  lymphatic  gan- 
glia are  connected  to  the  axillary  vessels  by  the  small 
branches  which  supply  them  :  several  lie  posterior  to  the 
edge  of  the  pectoral  muscle  ;  from  these  a  chain  continues 
up  to  the  coracoid  process,  and  are  continued  beneath  the 
clavicle  and  the  ganglia  in  the  neck  ;  several  also  lie  on 
the  subscapular  muscle,  and  some  are  scattered  indifferent- 
ly  through  this  space.  Some  of  the  conglobate  ganglia  of 
the  axilla  are  very  generally  diseased,  in  cases  of  malig- 
nant affections  of  the  breast,  and  must  therefore  be  remov- 
ed by  the  surgeon,  at  the  time  of  extirpating  the  latter. 


SECTION  III. 


DISSECTION    OF    THE    CAVITY    OF    THE    THORAX. 

THE  thorax  is  situated  at  the  upper  and  anterior  part  of 
the  trunk  ;  it  contains  the  lungs,  the  organs  of  respiration ; 
the  heart,  the  chief  agent  in  the  circulation  of  the  blood, 
also  several  nerves  and  vessels  passing  to  and  from  the 
heart,  and  through  the  cavity  ;  this  region  is  bounded  an- 
teriorly by  the  sternum  arid  costal  cartilages,  laterally  by 
the  ribs  and  intercostal  muscles,  posteriorly  by  the  verte- 
brae and  angles  of  the  ribs,  inferiorly  by  the  diaphragm, 
superiorly  by  the  several  muscles  connected  to  the  clavi- 
cle, first  rib  and  sternum,  and  by  the  different  parts  pass- 
ing into  or  out  of  the  cavity.  The  thorax,  viewed  external- 
ly, presents  a  very  different  form  before  and  after  the  up- 
per extremities  are  detached  from  it ;  in  the  former  state  it 
appears  of  great  transverse  width  above,  and  narrow  be- 
low ;  whereas  in  the  latter  condition,  it  is  seen  to  be  very 
contracted  above  and  expanded  below.  The  thorax  may 


74  DUBLIN    DISSECTOR. 

oe  compared  to  a  section  of  a  cone,  the  posterior  fourth 
being  removed,  the  three  anterior  parts  retained  and  united 
to  each  other.  The  axis  of  the  cavity  is  oblique  from 
•above  downwards  and  forwards  ;  the  base  of  the  thorax  is 
also  oblique  from  before,  backwards  and  downwards,  and 
the  apex  on  the  contrary  is  oblique  from  behind,  forwards 
and  downwards ;  hence  the  perpendicular  diameter  of  the 
thorax  is  much  greater  posteriorly  than  it  is  behind  the 
sternum.  The  apex  of  the  thorax  is  somewhat  truncated, 
and  presents  an  oval  opening,  longer  transversely  than 
from  before  backwards  ;  this,  the  superior  orifice  of  the  tlio- 
rax,  is  bounded  anteriorly  by  the  upper  edge  of  the  ster- 
num and  interclavicular  ligament,  posteriorly  by  the  last 
cervical  and  first  dorsal  vertebrae,  and  laterally  by  the 
first  rib  :  the  several  important  parts  which  pass  through 
this  opening  shall  be  noticed  afterwards.  The  inferior  cir- 
cumference of  the  thorax  is  five  or  six  times  more  exten- 
sive than  the  superior ;  it  is  bounded  by  the  xiphoid,  the 
last  true  and  all  the  false  costal  cartilages,  and  by  the  last 
dorsal  and  first  lumbar  vertebras:  its  longer  diameter  is 
also  transverse.  Open  the  cavity  by  dividing  the  carti- 
lages of  the  ribs  on  each  side  of  the  sternum,  and  raising 
the  latter  from  below  upwards ;  if  we  look  under  the  ster- 
num as  we  thus  slowly  raise  it,  we  perceive  that  space 
called  anterior  mediastinum  to  be  gradually  developed,  from 
the  right  and  left  pleurae  separating  from  each  other  as  we 
tear  the  loose  cellular  membrane,  which  naturally  con- 
nects the  pleura  and  pericardium  to  the  posterior  surface 
of  the  bone  :  when  the  sternum  is  removed,  this  region  is 
fully  exposed ;  it  is  described  as  being  of  a  triangular 
form,  the  base,  the  sternum ;  the  sides,  the  pleurae,  con- 
verging behind,  so  as  nearly  to  touch  each  other  ;  the  apex, 
the  small  portion  of  pericardium  left  uncovered  by  the 
pleuras ;  naturally,  however,  all  the  parts  within  the  tho- 
rax are  so  closely  applied  to  the  parietes,  that  no  space  or 
cavity  of  a  defined  form,  like  that  assigned  to  the  anterior 
mediastinum,  can  truly  be  said  to  exist.*  The  dissector, 

*  For  the  purpose  of  examining  the  morbid  appearances  after  death,  the  cavi- 
ties of  the  thorax  and  abdomen  are  generally  opened  at  the  same  time ;  an  incision, 
carried  from  the  top  of  the  sternum  to  the  symphisis  pubis,  through  the  integu- 
ments, muscles,  and  peritoneum,  will  bring  the  latter  cavity  into  view;  next  let 
the  skin  and  muscles  covering  the  front  of  the  thorax  be  turned  back,  which  will 
expoae  the  cartilages  connecting  the  ribs  with  the  sternum ;  immediately  at  their 
point  of  connexion  with  the  bone,  these  are  to  be  cut ;  in  doing  this  take  care  not 
to  wound  the  viscera  within. 

In  some  old  subjects,  where  the  cartilages  of  the  ribs  are  in  some  degree  ossified, 
a  saw  must  be  employed  :  all  the  cartilages,  except  those  of  the  first  rib,  being  di- 
vided, the  sternum  may  be  raised  like  the  lid  of  a  box,  and  a  very  convenient 
hinge  is  made  by  cutting  the  articulation  between  the  first  and  second  pieces  of 
the  sternum  on  the  inside,  opposite  the  second  rib  ;  the  figure  of  the  thorax  will 
llius  be  preserved,  and  a  sufficient  view  be  obtained  of  its  contents). 


DUBLIN    DISSECTOR.  75 

nowever,  may  cause  this  space  to  appear  more  distinct  by 
the  following  precaution :  before  you  divide  the  cartilages, 
push  your  fingers  from  the  abdomen  behind  the  sternum, 
and  break  down  the  cellular  connexions  between  it  and 
the  pleurae,  then  cut  the  cartilages  very  near  the  sternum, 
and  raise  the  latter ;  without  this  precaution  before  divi- 
ding the  cartilages,  the  pleura,  particularly  the  right,  will 
be  in  almost  every  instance  laid  open,  and  so  the  appear- 
ance of  the  anterior  mediastinum  injured.  This  region  in 
general  inclines  a  little  to  the  left  side  below,  in  conse- 
quence of  the  left  pleura  being  more  attached  to  the  peri- 
cardium, which  lies  rather  to  the  left  of  the  middle  line, 
whereas  the  right  pleura  is  connected  to  the  sternum  in  a 
vertical  line :  the  anterior  mediastinum  is  wider  superior- 
ly and  inferiorly  than  in  the  centre,  hence  some  compare 
it  to  the  letter  X,  and  describe  it  as  consisting  of  two  trian- 
gular spaces,  their  apices  joined  in  the  centre,  the  base  of 
one  towards  the  neck,  and  that  of  the  other  towards  the 
diaphragm :  the  superior  portion  contains  the  origins  of 
the  sterno-hyoid  and  thyroid  muscles,  and  the  remains  of 
the  thymus  body ;  inferiorly  there  is  much  loose  cellular 
membrane,  which  leads  from  the  neck  to  the  abdominal 
muscles,  also  lymphatic  ganglia,  and  close  to  the  sternum 
are  the  mammary  vessels,  and  the  triangulares  sterni  mus- 
cles. 

Next  examine  the  organs  on  each  side  of  the  thorax  ; 
these  are  the  lungs  and  their  investing  membranes  the 
pleurae  ;  in  almost  all  respects  these  organs  are  similar  on 
the  right  and  left  side,  and  therefore  either  may  be  select- 
ed for  examination ;  for  this  purpose  lay  open  one  side, 
suppose  the  right,  of  the  thorax,  by  sawing  through  the 
ribs  about  their  centre,  and  removing  their  anterior  por- 
tion ;  the  first  rib  may  be  left  uninjured ;  thus  the  cavity 
of  the  right  pleura  will  be  opened,  its  glistening  surface 
seen,  with  the  lung  lying  collapsed.  The  pleura  are  serous 
membranes,  their  internal  surface  is  smooth,  polished  and 
free ;  their  external  surface  is  connected  by  fine  cellular 
membrane  to  the  parietes  of  the  thorax,  and  to  the  tissue 
of  the  lungs,  over  which  they  are  reflected.  That  portion 
of  each  which  invests  the  lungs  is  called  pleura  pulmonalis, 
and  that  which  is  connected  to  the  parietes  pleura  parietalis 
or  costalis ;  the  latter  portion  of  the  membrane  is  much 
more  dense  and  strong  than  the  former;  each  pleura 
is  a  shut  sac,  and  contains  only  the  serous  vapour  it  ex- 
hales ;  for  although  the  lung  appears  within  the  cavity,  it 
is  yet  really  external  to  it  or  behind  it ;  internally  each 
pleura  presents  one  continuous  surface,  which  can  be 
traced  throughout  its  whole  extent;  thus  we  can  per- 


76  DUBLIN    DISSECTOR. 

ceive  that  the  right  pleura  passes  from  the  back  of  the 
sternum  to  form  the  side  of  the  anterior  mediastinum,  and 
arriving  at  the  forepart  of  the  pericardium  is  continued 
along  the  side  of  that  bag  as  far  back  as  the  root  of  the 
lung,  whence  it  is  reflected  over  the  anterior  surface  of 
this  organ,  sinking  into  its  fissures,  and  connecting  all  its 
lobules  to  each  other ;  having  thus  invested  the  whole  lung, 
it  arrives  at  the  posterior  surface  of  its  root,  from  which  it 
is  reflected  to  the  back  part  of  the  pericardium,  where  it 
approaches  the  opposite  pleura,  to  which  it  is  connected 
by  cellular  membrane ;  thence  it  passes  to  the  sides  of  the 
vertebrae,  thus  forming  the  side  of  the  posterior  mediasti- 
num (to  be  examined  presently  ;)  the  pleura  then  expands 
along  the  side  of  the  spine,  ascending  as  high  as  the  trans- 
verse process  of  the  sixth  or  seventh  cervical  vertebra,  and 
descending  to  the  diaphragm,  the  convex  surface  of  which 
it  covers  ;  on  this  muscle  also  it  is  reflected  from  the  low- 
er edge  of  the  root  of  the  lung  by  a  fold  called  ligamentum 
latum  pulmonis,  loose  and  triangular,  the  base  towards  the 
diaphragm,  one  side  connected  to  the  lung,  and  the  oppo- 
site to  the  mediastinum;  from  the  vertebra?,  the  pleura 
continues  to  pass  outwards,  lining  the  ribs  and  intercostal 
muscles,  as  far  forwards  as  the  side  of  the  sternum,  where 
the  sac  was  opened,  and  the  description  commenced.  The 
pleurae  are  of  a  conical  form,  the  apex  of  each  is  in  the 
neck,  covered  by  the  anterior  scalenus  and  subclavian  ar- 
tery, the  base  adheres  to  the  diaphragm ;  the  right  pleura  is 
shorter  but  broader  than  the  left,  which  is  long  and  nar- 
row ;  the  liver  on  the  right  side  and  the  heart  on  the  left 
cause  these  differences  to  exist ;  the  apex  of  the  right  is 
often  higher  in  the  neck  than  that  of  the  left.  The  two 
pleura  have  been  compared  to  two  bladders  placed  nearly 
parallel  to  each  other,  not  having  any  communication,  but 
touching  each  other  along  the  mesial  line ;  this  juxta-posi- 
tion  of  the  two  pleurae  between  the  sternum  and  vertebrae 
forms  a  sort  of  partition  between  the  right  and  left  sides 
of  the  thorax ;  this  partition  is  called  mediastinum ;  it  con- 
sists of  course  of  two  laminae,  right  and  left,  connected 
anteriorly  to  the  sternum,  posteriorly  to  the  spine ;  these 
laminae  are  separated  from  each  other  in  three  situations, 
in  order  to  enclose  certain  organs,  so  that  the  mediastinum 
is  divided  into — first,  the  anterior  part,  or  anterior  medias- 
tinum, which  has  been  already  examined ;  second,  into  a 
middle  part,  or  middle  mediastinum,  containing  the  heart 
and  pericardium ;  and  third,  into  a  posterior  mediastinum, 
which  lies  in  front  of  the  vertebrae,  and  which  the  student 
may  next  examine. 

The  posterior  mediastinum  extends  in  a  vertical  direction 


DUBLIN    DISSECTOR.  77 

from  the  third  to  the  tenth  dorsal  vertebra,  behind  the  pericar- 
dium and  roots  of  the  lungs,  and  in  front  of  the  spine ;  to  ob- 
tain a  view  of  the  parts  contained  in  it,  draw  the  right  lung 
forward,  and  to  the  left  side,  and  make  a  perpendicular 
division  of  the  right  pleura,  between  the  root  of  the  lung 
and  the  spine.  This  region  is  described  as  being  of  a  tri- 
angular form,  the  base  posteriorly,  the  pleurae  forming  its 
sides,  and  the  pericardium  its  apex ;  like  the  anterior  medi- 
astinum, however,  it  has  naturally  no  exact  figure,  the 
pleurse  being  folded  round  the  organs  which  lie  between 
them.  In  the  posterior  mediastinum  we  find  the  oesopha- 
gus and  eighth  pair  of  nerves,  the  thoracic  duct,  vena  azy- 
gos, descending  aorta,  splanchnic  nerves,  several  lympha- 
tic ganglia,  and  a  considerable  quantity  of  fine,  loose  cel- 
lular membrane ;  the  division  of  the  trachea,  also,  is  en- 
closed in  this  space,  just  at  its  commencement  The  oesoph- 
agus is  anterior  to  the  other  parts  in  the  posterior  medias- 
tinum ;  this  tube  having  passed  behind  the  left  division  of 
the  trachea,  enters  this  space,  arid  descends  obliquely  for- 
wards behind  the  pericardium  and  before  the  aorta ;  above, 
it  lies  to  the  right  side  of  this  vessel,  but  below  it  is  to  the 
left ;  in  the  lower  part  of  its  course  it  is  surrounded  by 
branches  of  the  eighth  pair  of  nerves,  and  enlarging  a  lit- 
tle, it  perforates  the  fleshy  part  of  the  diaphragm,  opposite 
the  ninth  or  tenth  dorsal  vertebra,  and  joins  the  stomach. 
The  eighth  pair  of  nerves  having  passed  behind  the  roots  of 
the  lungs,  attach  themselves  to  the  oesophagus,  and  form 
by  their  branches  a  plexus  around  it,  (the  cesophageal  plexus)  ; 
the  left  nerve  then  descends  on  the  fore,  and  the  right  on 
the  back  part  of  this  tube  to  the  stomach.  The  thoracic 
aorta  enters  this  region  about  the  fourth  or  fifth  dorsal  ver- 
tebra, and  descends  along  the  left  side  of  the  spine;  about 
the  eleventh  or  twelfth  dorsal  vertebra  it  passes  between 
the  crura  of  the  diaphragm  into  the  abdomen;  in  this 
course  the  aorta  furnishes  the  following  branches  :  two  or 
three  bronchial  arteries,  which  go  to  the  lungs,  as  many 
cesophageal  branches,  and  nine  or  ten  pair  of  intercostal 
arteries,  whose  name  implies  their  destination. 

The  vena  azygos  commences  in  the  abdomen  by  a  small 
branch  from  one  of  the  superior  lumbar  veins,  enters  the 
thorax  behind  the  right  side  of  the  posterior  mediastinum, 
covered  by  the  right  pleura;  and  opposite  the  third  or 
fourth  dorsal  vertebra  it  arches  forwards  over  the  root  of 
the  right  lung,  and  opens  into  the  superior  vena  cava,  as 
that  vessel  is  entering  the  pericardium. 

The  vena  azygos  in  this  course  receives  the  bronchial, 
oesophageal,  and  intercostal  veins ;  those  of  the  left  side 
often  unite  into  one  branch,  which  passing  behind  the 

7* 


78  DUBLIN    DISSECTOK. 

aorta,  joins  opposite  the  sixth  or  seventh  vertebra,  the 
principal  trunk  on  the  right  side.  The  thoracic  duct  also 
commences  in  the  abdomen,  on  the  second  or  third  lumbar 
vertebra  behind  the  aorta,  in  a  sinus,  called  receptaculum 
chyli ;  contracting  in  size  it  enters  the  posterior  mediasti- 
num, along  with,  and  to  the  right  side  of  the  aorta  ;  it  as- 
scends  between  this  vessel  and  the  vena  azygos,  imbeo^ded 
in  fat,  and  opposite  to  the  fifth  or  sixth  dorsal  vertebra  it 
attaches  itself  to  the  back  of  the  oesophagus,  runs  obliquely 
along  it,  behind  the  arch  of  the  aorta,  to  the  left  side,  and 
ascends  in  the  neck  behind  the  left  carotid  artery  and 
jugular  vein,  as  high  as  the  sixth  cervical  vertebra ;  it  then 
bends  downwards  and  outwards,  and  enters  the  left  sub- 
clavian,  just  before  it  joins  the  jugular  vein.  The  coats  of 
the  thoracic  duct  are  so  fine  and  thin,  that  it  is  often  diffi- 
cult to  see  or  trace  this  vessel.  (For  a  more  particular  de- 
scription of  it,  see  the  Anatomy  of  the  Absorbent  System.) 
The  splanchnic  nerves  arise  by  four  or  five  filaments  from  the 
dorsal  ganglions  of  the  sympathetic  nerve  ;  the  first  is  from 
the  fifth  or  sixth  ganglion,  the  rest  arise  in  succession  be- 
low it ;  all  unite  and  form  the  splanchnic  nerves,  which 
descend  obliquely  forwards  on  each  side  of  the  aorta,  along 
with  which  they  enter  the  abdomen,  where  each  terminates 
in  a  large  ganglion,  termed  semilunar;  these  two  ganglions 
are  joined  together  by  numerous  branches,  which  constitute 
the  c&liac,  or  solar  plexus,  from  which  the  greater  number 
of  the  abdominal  viscera  are  supplied  with  nerves.  In  the 
dissection  of  the  posterior  mediastinum,  the  sympathetic 
nerve  is  also  seen  on  each  side ;  it  does  not  lie  in  this 
space,  but  descends  external  to  it,  between  the  pleurae  and 
the  heads  of  the  ribs ;  opposite  each  intercostal  space  it 
forms  a  ganglion,  from  which  some  branches  pass  to  join 
the  dorsal  spinal  nerves,  others  to  form  the  great  splanch- 
nic ;  and  at  the  lower  part  of  the  thorax,  two  or  three  fila- 
ments often  unite  to  form  a  small  nerve,  called  lesser  splanch- 
nic, which  enters  the  abdomen  behind  or  through  the  crura 
of  the  diaphragm,  and  joins  the  renal  plexus  of  nerves. 
The  sympathetic  on  each  side  enters  the  thorax  close  to 
the  neck  of  the  first  rib,  where  it  forms  a  large  ganglion ; 
it  passes  from  this  cavity  by  a  very  small  filament,  between 
the  crus  of  the  diaphragm  and  the  psoas  magnus,  into  the 
abdomen,  where  it  again  enlarges  considerably. — (See  the 
Anatomy  of  the  Nervous  System.)  The  division  of  the 
trachea,  the  last  part  of  any  importance  connected  with 
the  posterior  mediastinum,  does  not,  strictly  speaking,  lie 
in  this  space,  but  like  the  heart  and  great  vessels,  it  is  in 
the  middle  mediastinum,  or  between  the  anterior  and  pos- 
terior,; this  tube  can  be  more  conveniently  examined  after- 


DUBLIN    DISSECTOR.  79 

wards,  when  we  are  dissecting  the  parts  which  pass 
through  the  upper  opening  of  the  thorax.  Next  examine 
the  lungs. 

The  lungs  are  situated  at  either  side  of  the  spine,  and 
when  distended  with  air,  as  they  constantly  are  during  life, 
they  so  exactly  fill  each  side  of  the  thorax  that  the  pleura? 
pulmonalis  and  costalis  are  always  in  such  perfect  apposi- 
tion, that  there  never  can  be  any  intermediate  cavity ;  they 
are  of  a  conical  figure,  the  apex,  above,  rises  into  the  neck 
a  little  above  the  level  of  the  first  rib,  and  in  general  higher 
on  the  right  than  on  the  left  side ;  the  base,  below,  concave, 
rests  on  the  diaphragm :  the  external  surface  convex,  and 
divided  into  two  or  three  parts  by  a  deep  fissure ;  the  in- 
ternal slightly  concave,  and  attached  near  its  centre  by 
the  root  to  the  heart  and  great  vessels ;  the  posterior  edge 
of  each  lung  is  thick,  round  and  vertical ;  the  anterior  is 
thin,  irregular,  oblique  and  shorter  than  the  posterior  ;  that 
of  the  left  side  is  in  general  notched  opposite  the  apex  of 
the  heart.  The  right  lung  is  broader  but  shorter  than  the 
left,  the  former  consists  most  commonly  of  three  lobes,  the 
latter  has  only  two.  The  great  fissure  of  each  lung  de- 
scends obliquely  forwards ;  it  commences  behind  the  apex, 
and  ends  in  front  of  the  base ;  it  divides  the  substance  of 
the  lung,  to  a  great  depth  into  two  lobes ;  one  is  anterior 
and  superior,  and  the  other  posterior  and  inferior ;  the  lat- 
ter is  somewhat  larger  ;  on  the  right  side  a  small  fissure 
leads  from  about  the  middle  of  the  great  one,  forwards  to 
the  edge  of  the  lung,  and  cuts  off  the  middle  lobe  from  the 
superior ;  this  fissure  does  not  penetrate  to  the  same  depth 
as  the  great  one  does ;  it  is  sometimes  absent,  and  in  some 
subjects  it  exists  on  the  left  as  well  as  on  the  right  side. 
The  root  of  each  lung  is  situated  a  little  above  the  centre 
of  the  internal  surface,  and  about  two-thirds  from  the  an- 
terior edge  ;  the  phrenic  nerve  and  a  few  filaments  of  the 
pneumogastric  lie  anterior  to  it,  and  the  pulmonary  plexus 
is  posterior  to  it ;  the  fold  called  ligamentum  latum  is  be- 
low it ;  it  consists  of  several  vessels  and  nerves  connected 
together  by  cellular  tissue,  and  all  enclosed  between  the 
laminae  of  the  pleura ;  dissect  off  this  membrane  from  the 
forepart  of  the  root,  and  we  shall  observe  the  two  pul- 
monary veins  inferior,  but  anterior  to  the  pulmonary 
artery,"  which  is  immediately  above  and  behind  them  ;  pos- 
terior and  superior  to  the  artery  is  the  bronchial  tube  ;  a 
quantity  of  cellular  tissue  connects  these  vessels,  and  con- 
tains the  bronchial  arteries  and  veins,  also  several  nerves, 
which  are  derived  from  the  pulmonary  plexus.  In  the 
root  of  the  left  lung  the  bronchial  tube  is  rather  inferior 
to  the  artery,  but  still  posterior  to  it,  as  on  the  right  side. 


80  DUBLIN    DISSECTOR. 

The  lungs  have  a  peculiar  soft,  emphysematous  feel,  and 
are  so  light  as  to  float  in  water  ;  their  colour  is  grey,  in- 
terspersed with  spots  of  dark  blue  or  blackish  tint :  the 
younger  the  subject  the  redder  the  lungs  will  be  found ;  in 
the  adult  they  are  generally  grey,  and  slightly  streaked 
with  dark  lines ;  in  the  old  they  are  usually  mottled  with 
blue  or  black  spots,  which  exist,  not  merely  on  the  surface, 
but  through  their  substance.  The  lungs  are  composed  of 
the  ramifications  of  the  pulmonary  arteries  and  veins,  of 
the  bronchial  arteries  and  veins,  of  the  pulmonary  nerves, 
of  lymphatic  vessels  and  ganglia,  and  of  the  ramifications 
of  the  bronchial  tubes,  which  end  in  numerous  air  cells  ; 
these  are  collected  at  first  in  clusters,  and  joined  by  cellu- 
lar membrane  into  the  lobules :  these  last  are  again  united 
into  larger  masses  by  the  pleura,  so  as  to  form  lobes ;  the 
air-cells  are  the  terminations  of  the  bronchial  vessels ;  they 
are  globular,  are  lined  by  mucous  membrane,  and  covered 
by  a  fibrous,  or,  as  some  suppose,  a  muscular  lamina ;  each 
bronchus  divides  into  two  branches,  these  again  subdivide 
into  two,  and  so  on  in  binary  order ;  these  canals  increase 
in  number,  and  diminish  in  size ;  their  final  capillary 
branches  end  in  small  sacs  or  air-cells;  these  constitute 
the  principal  bulk  of  the  lung :  the  larger  bronchial  tubes 
are  composed  of  the  same  materials  as  the  trachea,  but  in 
the  smaller  branches  there  is  no  cartilaginous  structure. 
On  their  delicate  parietes  the  fine  capillaries  of  the  pul- 
monary arteries  and  veins  are  spread,  and  here  during  life 
is  effected  that  important  change  in  the  blood,  from  venous 
to  arterial,  which  appears  to  be  the  great  design  of  the 
function  of  respiration.  The  soft  and  yielding  tissue  of 
the  lungs  admits  of  the  free  entrance  and  rapid  circulation 
of  the  air  through  their  cells,  all  which  become  distended 
in  the  moment  of  inspiration ;  in  this  act  the  lungs  are 
wholly  passive,  the  air  distending  them  in  the  exact  pro- 
portion with  which  the  parietes  of  the  chest  are  expanded; 
in  expiration,  the  contraction  of  the  thorax  expels  a  great 
portion  of  the  air  from  the  cells,  and  thus  the  lungs  be- 
come diminished  in  capacity  ;  in  effecting  this  change,  the 
elasticity,  aided  in  all  probability  by  the  irritable  or  mus- 
cular energy  of  these  organs,  may  assist  the  muscular  and 
elastic  power  of  the  parietes  of  the  chest.  In  expiration 
the  air-cells  are  not  wholly  emptied  ;  no  power  can  com- 
pletely discharge  the  air  from  lungs  that  have  once  breath- 
ed.— See  Anatomy  of  the  Diaphragm. 

[There  being  no  other  organ  of  size,  in  the  cavity  of  the  thorax, 
besides  the  lungs  and  the  heart,  and  the  latter  being  on  an  average  or 
the  size  of  the  fist  of  the  individual,  it  is  obvious  that  from  an  ex- 
ternal examination  of  the  thorax,  we  can  draw  a  sufficiently  correct 


DUBLIN    DISSECTOR.  81 

inference  as  to  the  development  of  the  lungs  within  ;  neither  is  it  the 
absolute  size  of  the  thorax,  that  indicates  the  best  development  of 
lungs,  but  its  size  as  compared  with  the  rest  of  the  body  and  particu- 
larly the  expansion  of  its  antero-posterior  diameter  ;  the  volume  of 
the  right  lung  and  its  capacity  are  greater  than  that  of  the  left,  and 
this  is  in  accordance  with  the  fact,  that  the  right  bronchus  is  much 
larger  than  the  left ;  may  not  the  difference  in  the  size  and  length  of 
the  two  bronchii  (the  left  being  nearly  twice  as  long  as  the  right,  and 
but  about  half  its  calibre)  and  the  smaller  capacity  of  the  left  lung, 
have  some  relation  with  the  fact,  that  this  organ  is  more  affected 
by  tubucular  disease,  than  the  right.  It  is  estimated  that  the  capa- 
city of  the  lungs  is  such  as  to  contain  one  hundred  and  forty-five 
cubic  inches  of  air,  and  that  by  each  act  of  expiration,  thirty  cubic 
inches  are  thrown  off;  we  know  of  an  individual  who  can  displace 
one  gallon  of  water  by  a  single  expiration,  without  great  effort. 

The  specific  gravity  of  the  lungs  after  inspiration  is  less  than  that 
of  water,  but  in  the  foetus,  and  still  born  infants,  it  is  greater  than 
that  of  water,  in  which  it  sinks,  a  fact  of  much  importance  in  legal 
medicine,  and  which  in  its  practical  application  constitutes  the  hy- 
drostatic test;  the  absolute  weight  of  the  lungs,  also  differs  at  dif- 
ferent periods.  In  infants  before  respiration  it  is  to  the  weight  of  the 
body,  as  one  to  sixty,  after  respiration,  as  one  to  thirty,  owing  proba- 
bly to  the  increased  determination  of  blood  through  the  pulmonary 
vessels ;  in  the  adult  subject  of  usual  stature,  it  is  said  that  the  weight 
of  the  lungs,  is  about  three  pounds  ;  in  disease  it  is  often  very  much 
changed.  The  apex  of  the  lung  rises  above  the  level  of  the  first  rib, 
sometimes  an  inch,  and  even  two  inches,  and  it  has  been  suggested 
that  the  compression  of  the  lungs  by  the  edge  of  the  first  rib  may 
produce  irritation,  and  that  this  may  be  the  reason  that  tubercles,  are 
generally  first  developed  in  the  apices.] 

The  pleurse  and  lungs  are  the  seat  of  many  morbid 
changes ;  the  pleura,  when  inflamed,  becomes  thickened 
and  vascular,  and  presents  a  deposit  of  lymph  on  the  sur- 
face, which  commonly  causes  an  adhesion  between  the 
pleura  costalis  and  pulmonalis  to  a  very  variable  extent ; 
when  these  adhesions  are  recent,  they  are  soft  and  easily 
broken,  but  when  of  long  standing  they  become  strong  and 
resisting  :  adhesions  of  different  extent  and  length  are  very 
common  appearances.  Portions  of  the  pleura  costalis  are 
found  sometimes  converted  into  bony  plates,  and  apparent- 
ly without  having  caused  any  inflammation  or  inconveni- 
ence. The  cavity  of  each  pleura  is  also  the  seat  of  effu- 
sion ;  if  of  water  or  serum,  it  is  named  hydrothorax,  if  of 
pus,  empyema ;  the  operation  of  paracentesis,  or  tapping, 
is  frequently  required  in  the  latter  case.  The  place  usual- 
ly selected  for  this  operation,  is  about  midway  in  the  fifth 
intercostal  space,  just  in  front  of  the  digitations  of  the  ser- 
ratus  magnus  muscle. 

The  lungs  are  often  found  in  a  state  of  inflammation, 
(pneumonia),  this  is  denoted  by  increased  density,  weight, 


82  DUBLIN    DISSECTOR. 

and  colour,  sometimes  dark,  sometimes  very  florid :  the  af- 
fected portion  is  often  so  heavy  as  to  sink  in  water ;  the 
dark  colour  from  the  gravitation  of  blood  to  a  depending 
part,  must  not  be  confounded  with  that  arising  from  dis- 
ease. Inflammation  sometimes  ends  in  abcess,  which  may 
open  into  the  trachea  or  into  the  pleura,  and  so  cause  em- 
pyema.  The  lungs  arc  very  subject  to  tubercles,  which 
present  great  variety  in  size,  from  a  pin's  head  to  that  of 
a  walnut ;  when  small  they  are  firm,  when  large  they  be- 
come soft,  suppurate  in  the  centre,  and  form  abscesses  or 
vomicse,  which  often  communicate  with  the  bronchial  tubes. 
Tubercles  are  often  found  in  the  upper  part  of  the  left 
lung,  when  the  remainder  of  both  organs  is  healthy.  The 
lungs  are  also  occasionally  the  seat  of  cancerous  and  fun- 
goid tubercle  and  tumour.  We  shall  next  direct  our  at- 
tention to  the  pericardium  and  the  heart. 

The  pericardium  is  a  strong  fibro-serous  membrane,  in 
the  form  of  a  conical  bag,  whose  base  is  below  and  apex 
above ;  it  is  larger  than  the  heart,  which  it  encloses,  to- 
gether with  a  portion  of  the  great  vessels  connected  to  it, 
and  over  whose  surface  its  internal  or  serous  layer  is  re- 
flected :  the  external  fibrous  lamina  is  connected,  inferior- 
ly,  to  the  central  division  of  the  cordiform  tendon  of  the 
diaphragm,  and  to  some  of  its  fleshy  portion  between  the 
central  and  the  left  divisions  of  that  tendon  ;  anteriorly  to 
the  pleurae,  and  to  the  parts  contained  in  the  anterior  me- 
diastinum ;  posteriorly,  to  the  oesophagus  and  to  the  other 
parts  in  the  posterior  mediastinum ;  superiorly,  it  is  con- 
tinued along  the  outer  coat  of  the  great  vessels,  while  the 
serous  layer  is  reflected  on  these  towards  the  heart.  On 
each  side  it  is  in  a  similar  manner  connected  to  the  pul- 
monary vessels ;  the  pleura  and  the  phrenic  nerve  also  are 
attached  to  it  in  this  situation.  The  connexion  between  it 
and  the  tendon  of  the  diaphragm,  particularly  towards  its 
forepart,  is  very  intimate  ;  in  the  adult  they  are  almost  in- 
separable, not  so,  however,  in  the  foetus.  Open  this  bag, 
and  we  shall  see  that  it  is  lined  throughout  by  a  smooth 
serous  membrane,  which,  if  we  trace  to  the  superior  part 
of  the  sac,  we  shall  perceive  to  be  reflected  on  the  vena 
cava  on  the  right  side,  on  the  aorta  in  the  middle,  and  on 
the  pulmonary  artery  on  the  left  side ;  on  these  three  ves- 
sels it  descends  towards  the  heart :  there  is  a  longer  por- 
tion of  the  aorta  covered  by  the  serous  membrane,  than  of 
the  vena  cava  or  pulmonary  artery,  which  two  are  nearly 
equal  in  this  respect.  The  serous  layer  is  reflected  on  the 
superior  cava,  opposite  the  entrance  of  the  vena  azygos ; 
as  it  descends  along  that  vessel  it  nearly  surrounds  it,  ex- 
cept a  small  portion  of  it  posteriorly  ;  from  the  vena  cava 


DUBLIN    DISSECTOR.  83 

it  continues  to  the  right  auricle,  which  it  covers  anteriorly 
and  on  the  right  side  ;  from  this  it  passes  on  the  right  pul- 
monary veins,  covers  these  partially,  and  is  thence  reflect- 
ed to  the  fibrous  layer ;  from  the  lower  part  of  the  right 
auricle  it  is  continued  partly  round  the  inferior  cava,  and 
from  it  also  it  is  reflected  to  the  fibrous  layer.  On  the 
aorta  the  serous  layer  descends  at  first  on  the  forepart, 
afterwards  on  its  sides  and  back  part,  so  as  to  encircle  it ; 
near  the  heart  it  passes  from  it  over  the  pulmonary  artery, 
so  as  to  connect  these  vessels  to  each  other,  leaving  of 
course  uncovered  so  much  of  each  as  are  in  apposition  ; 
along  these  vessels  the  serous  membrane  descends  to  the 
ventricles,  and  having  covered  all  the  anterior  surface  of 
the  heart,  it  turns  round  its  apex,  covers  the  posterior  sur- 
face, and  ascending  on  it  as  high  as  the  upper  edge  of  the 
left  auricle,  it  is  thence  reflected  on  the  fibrous  layer  in 
front  of  the  posterior  mediastinum  ;  from  the  left  auricle 
also  it  extends  to  the  left  pulmonary  veins,  from  which  it 
is  continued  to  the  fibrous  layer,  and  on  this  we  can  trace 
it  in  an  uninterrupted  course  to  that  point,  at  which  we 
commenced  its  description. 

The  pericardium,  by  its  fibrous  lamina,  is  of  use  in  fix- 
ing the  heart  in  its  situation,  and  strengthening  its  parie- 
tes,  so  as  to  resist  over  distention ;  this  tunic  also,  by  its 
elasticity,  may  assist  in  the  subsequent  contraction  of  its 
cavities,  while  the  serous  layer  being  always  lubricated  by 
a  fine  fluid,  facilitates  the  motion  of  the  heart  When  the 
pericardium  is  fully  opened,  the  right  auricle,  the  two  cavse, 
the  appendix  of  the  left  auricle,  the  right  or  anterior  ven- 
tricle, that  small  portion  of  the  left  which  forms  the  apex 
of  the  heart,  the  aorta  and  pulmonary  artery,  also  branch- 
es of  the  coronary  vessels,  ramifying  on  the  anterior  sur- 
face of  the  heart,  all  come  into  view. 

The  pericardum  is  liable  to  inflammation  :  this  is  not  a 
very  common  disease  ;  in  this  state  it  is  crowded  with  mi- 
nute vessels,  carrying  florid  blood ;  it  is  also  more  pulpy 
and  thicker  than  natural ;  extra vasated  coagulable  lymph 
is  found  loosely  connecting  it  to  the  heart ;  this  sometimes 
has  a  reticulated  or  lace-like  appearance,  and  portions  of 
it  float  in  the  serous  fluid,  which  exists  in  the  cavity.  In 
some  cases  large  quantities  of  pus  are  formed,  without 
any  appearance  of  ulceration,  but  always  accompanied 
with  a  thickened  state,  and  a  deposition  of  coagulable 
lymph  on  the  internal  surface  of  the  membrane.  The 
presence  of  a  small  quantity  of  fluid  in  the  pericardium 
after  death,  is  not  to  be  set  down  as  a  morbid  appearance, 
or  confounded  with  the  disease  called  hydrops  pericardii, 
as  in  every  healthy  body  a  few  drachms  of  fluid  are  found 


84  DUBLIN    DISSECTOR. 

in  the  bag  of  the  pericardium,  arising  from  the  condensa- 
tion of  the  natural  exhalation,  which  exists  in  all  serous 
cavities,  or  the  oozing  out  of  the  blood  from  the  contrac- 
tion of  the  heart  after  death. 

[The  pericardium  is  sometimes  entirely  absent,  but  this  is  rare  :  it 
sometimes  appears  to  be  wanting  in  consequence  of  a  complete  ad- 
hesion to  the  surface  of  the  heart.  This  organ  is  partially  converted 
into  bone,  and  one  instance  is  recorded  in  which  this  conversion  was 
complete.  Three  forms  of  effusion  may  coexist  with  pericarditis, 
serum,  pus,  and  blood,  and  the  quantity  is  sometimes  very  great,  thus 
cases  are  recorded,  of  eight  pounds  of  serum,  of  four  quarts  of  pus, 
arid  of  one  quart  of  blood,  having  been  found.  The  false  membrane 
of  pericarditis  varies  in  thickness  from  one  line  to  nearly  an  inch  ; 
inflammation  of  the  fibrous  lamina  of  the  pericardium,  occurs  some- 
times by  metastasis  from  other  parts  of  the  body.] 

The  heart  is  placed  obliquely  between  the  lungs,  the 
base  of  it  is  superior,  posterior  to  the  right  side,  and  near 
to  the  spine,  while  the  apex  points  towards  the  costal  end 
of  the  cartilage  of  the  sixth  rib  on  the  left  side,  and  during 
life  can  be  felt  pulsating  a  little  above  and  below  this 
rib ;  the  heart  is  retained  in  situ  by  the  pericardium,  and 
by  the  great  vessels;  it  is  subject,  however,  to  a  slight 
change  of  position,  according  as  that  of  the  body  is  altered, 
as  well  as  from  the  different  states  of  inspiration  and  ex- 
piration. The  heart  consists  of  four  cavities,  two  ventri- 
cles, and  two  auricles ;  these  the  student  may  examine  in 
that  order  or  course  which  the  blood  pursues  in  passing 
through  this  organ.  Suppose  the  two  vense  cavse  pour 
their  blood  into  the  right  auricle,  so  as  to  distend  it,  the 
parietes  of  this  cavity  then  contract,  and  empty  its  con- 
tents into  the  right  ventricle ;  this  next  propels  the  blood 
into  the  pulmonary  artery,  the  branches  of  which  convey 
it  through  the  lungs ;  from  these  organs  it  is  returned  by 
the  four  pulmonary  veins,  two  on  each  side,  into  the  left 
auricle ;  from  this  cavity  it  is  forced  into  the  left  ventricle, 
which  then  propels  it  into  the  aorta,  through  whose 
branches  it  is  conveyed  to  all  parts  of  the  body,  whence  it 
is  again  returned  to  the  heart  by  the  veins.  The  superior 
vena  cava  is  seen  descending  obliquely  forwards  and  in- 
wards within  the  pericardium,  and  joining  the  upper  and 
back  part  of  the  right  auricle.  Of  the  inferior  cava  but  a 
short  portion  is  seen  within  the  pericardium ;  this  vessel 
lies  on  a  plane  posterior  to  the  superior  cava,  and  passing 
obliquely  upwards,  backwards,  and  inwards,  joins  the 
lower  and  back  part  of  the  auricle.  Between  these  two 
veins  the  right  auricle  is  situated ;  it  is  somewhat  square, 
its  posterior  part,  between  the  two  cavse,  is  called  the  sinus; 
the  anterior  loose  portion,  the  auricular  appendix  or  process ; 


DUBLIN    DISSECTOR.  85 

the  right  auricle  is  connected  inferiorly  to  the  right  ven- 
tricle, and  partly  rests  on  the  diaphragm;  on  the  right 
side  it  is  free,  and  on  the  left  it  is  connected  to  the  left 
auricle  ;  lay  open  this  cavity  by  a  perpendicular  incision 
from  the  superior  down  to  within  half  an  inch  of  the  infe- 
rior cava,  from  the  centre  of  this  make  a  transverse  cut 
towards  the  anterior  part  of  the  auricle,  wash  out  the 
blood,  and  we  may  then  observe  at  the  back  part  of  the 
sinus  the  openings  of  the  two  cav&,  and  between  these  a 
slight  projection,  tuberculum  Loweri ;  and  in  the  auricular 
appendix  the  muscular  fibres  called  musculi  pectinati.  We 
can  also  now  perceive  that  the  left  or  internal  side  of  the 
auricle  is  formed  by  a  thin  sheet  of  membranous  and 
muscular  substance ;  this  is  the  septum  auricularum ;  on 
the  inferior  part  of  this  we  may  observe  a  depression,  the 
fossa  ovalis,  immediately  above  the  inferior  cava,  and  sur- 
rounded in  part  by  a  thick  lip,  named  its  annulus ;  at  the 
upper  and  deeper  part  of  this  fossa  we  frequently  find  a 
small  oblique  passage  leading  into  the  left  auricle,  its  ob- 
liquity, however,  prevents  any  communication  taking 
Elace  during  life ;  in  the  foetus  before  birth  this  was  a 
ree  opening,  the  foramen  oxale,  between  the  two  auricles. 
Anterior  to  the  opening  of  the  inferior  cava,  we  observe 
the  semilunar  fold  of  the  lining  membrane,  the  Eustachian 
valve:  this  valve  is  connected  by  its  convex  edge  to  the 
angle  between  the  vein  and  auricle ;  its  concave  edge  is 
loose,  and  looks  backwards  and  to  the  right  side ;  its  su- 
perior cornu  is  connected  to  the  anterior  or  the  left  limb 
of  the  fossa  ovalis,  and  the  inferior  to  the  forepart  of  the 
vena  cava  ;  this  cornu  is  sometimes  continued  round  that 
vessel  to  the  posterior  limb  of  the  fossa  ovalis :  in  the 
adult  and  old  this  valve  is  often  reticulated  and  imperfect ; 
in  the  foetus  it  is  generally  more  perfect  and  large,  hence 
it  is  considered  by  many  as  being  of  use  at  that  period  in 
directing  the  blood  from  the  inferior  cava  at  once  into  the 
left  auricle  through  the  foramen  ovale,  and  preventing  its 
mixing  with  that  from  the  superior  cava.  To  the  left  side 
of  the  Eustachian  valve,  between  it  and  the  ventricle,  is 
the  orifice  of  the  coronary  vein,  which  is  also  partly  covered 
by  a  semilunar  fold  of  membrane,  [the  valve  of  Theoesius]  that 
secures  this  opening  against  the  re-entrance  of  the  blood 
during  the  contraction  of  the  auricle ;  this  valve  also  is 
often  imperfect;  on  different  parts  of  the  auricle  small 
orifices  may  be  often  seen,  (foramina  T^hebesii  ;)  these  are 
probably  the  extremities  of  small  veins. 

In  the  anterior  part  of  the  auricle  we  see  the  small  cir- 
cular opening  of  the  appendix,  inferior  to  which,  and  op- 
posite the  tuberculum  Loweri,  is  the  large  orifice  leading 

8 


86  DUBLIN    DISSECTOR'. 

into  the  right  ventricle  ;  this,  the  right  auricula-ventricular' 
opening,  is  circular  and  surrounded  by  a  dense  white  line, 
which  has  been  erroneously  described  as  the  right  tendon 
of  the  heart.-  We  may  next  examine  the  right  ventricle  : 
for  this  purpose  open  its  cavity,  by  raising  the  anterior 
wall  in  the  form  of  a  flap  from  below,  making  one  incision 
along  its  right  side,  and  the  other  near  the  septum  cordis. 
The  right  ventricle  is  triangular,  its  base  is  joined  to  the  au- 
ricle, the  apex  is  a  little  above  the  apex  of  the  heart ;  the 
right  is  separated  from  the  left  ventricle  by  a  thick  muscu- 
lar lamina  (the  septum  cordis :)  the  parietes  of  this  cavity 
are  rendered  very  irregular  internally  by  numerous  mus- 
cular projections,  the  carnea  column®  ;  some  of  these  are 
attached  throughout  their  whole  length,  others  are  fixed  by 
their  extremities,  and  loose  in  their  centre,  and  a  third  spe- 
cies are  fixed  by  one  end  to  the  fleshy  substance  of  the 
heart,  by  the  other  to  thin  tendinous  cords  [chordae  tendinea] 
whicb  are  attached  to  the  auricular  valves  ;  the  carneae  co~ 
lumnee  take  various  directions,  and  are  all  covered  by  the 
fine  lining  membrane  of  the  heart.  At  the  base  of  this  ca- 
vity we  observe  the  auricular'  and  arterial  openings,  the 
latter  is  superior,. anterior  and  to  the  left  side  of  the  former ; 
from  the  margin  of  the  auricular  opening  a  fold  of  the 
lining  membrane  descends  into  the  ventricle,  the  inferior 
loose  edge  of  which  divides  into  three  portions,  each  end- 
ing in  a  very  irregularly  notched  margin,  to  which  the 
chorda?  tendineae  are  attached ;  these  are  the  tricuspid 
valves,  one  division  is  anterior  ;  the  second  is  posterior,  on- 
the  septum  cordis,  and  the  third,  which  is  the  largest,  is  to 
the  left  side,-  and  separates  the  auricular  from  the  arterial 
opening  ;  many  of  the  tendinous  threads  are  connected  to 
the  dorsum,  as  well  as  to  the  edge  of  these  foldsr  and  cross 
each  other  as  they  run  to  the  ca<rnea3  columnse.  The  use 
of  the  tricuspid  valves  is  to  prevent  the  reflux  of  the  blood 
from  the  ventricle  into  the  auricle ;  as  the  former  cavity  is 
being  distended,  the  blood  separates  the  valves  from  the 
parietes  of  the  ventricle,' and  thus  becomes  situated  on  their 
outer  side  ;'  when  the  ventricle  then  contrrvcts,  it  presses 
the  blood  against  these  folds,  which-  are  thus- approximated 
to  each  other,  and  slightly  raised  against  the  opening  so  as 
to  close  it ;  the  carnese  eolumnse  at  the  same  time  contract- 
ing make  tense1  the  chordee  tendraea3,  and  thus  accomplish, 
the  two  objects,  1st,  of  completely  approximating  the 
valves ;  and  2d,  of  preventing  their  being  reversed  or 
thrown  up  into  the  auricle.  The  orifice  of  the  pulmonary 
artery  is  small,  and  situated  at  the  highest  point,  and  at  the 
left  extremity  of  the  ventricle,  the  surface  of  which  be- 
comes smooth  as  it  approaches  it ;  this  vessel  is  connected 


DUBLIN:  DISSECTOR.  87 

;to  the  ventricle  by  the  external  and  internal  serous  mem- 
branes of  the  heart,  between  which  its  fibrous  coat  is  con- 
nected to  the  fleshy  fibres  of  the  ventricle  by  three  roots, 
-convex  towards  the  heart,  and^marked  internally  each  by 
a  distinct  white  line ;  from  this  arterial  opening  three  folds, 
the  semilunar  valves,  extend  into  the  'Vessel,  the  convex  edge 
of  each  is  fixed  to  the  white  line  at  each  of  the  roots  of  the 
artery  ;  the  concave  is  loose,  but  thick,  and  contains  in  its 
centre  a  small  tubercle,  the  corpus  Arantii  or  sesamoideum. 
The  use  of  these  valves  ^is  to  prevent  the  blood  returning 
from  the  artery  into  the  ventricle,  for,  as  the  former  be- 
comes distended,  the  blood  fiowsalongbehind  these  valves, 
[into  the  sinuses  of  vals-alva,]  separates  them  from  the  sides 
•of  the  artery,  and  so  approximates  "them  to  each  other  ; 
and  when  the  artery  contracts,  it  presses  the  blood  so 
strongly  against  these  valves  as  nearly  to  intercept  the 
•opening,  and  cause  the  blood  to  flow  onwards  through  the 
; artery ;  the  corpora  Arantii  are  supposed  to  be  of  use  in 
giving  additional  strength  towards  the  centre  of  the  open- 
ing, where  the  pressure  will  be  greatest;  the  semilunar 
valves,  both  -in  the  'pulmonary  artery  *and  in  'the  aorta, 
while  they  support  the  column  of  blood  in  these  vessels, 
cannot  wholly  prevent  its  regurgitation  to  the  heart.  The 
pulmonary  artery  ascends  obliquely  backwards  for  about 
•two  inches  and  a  half  within  the  pericardium  ;  and  just  as 
it  escapes  from  this  cavity  it  divides  into  the  right  and  lelP 
branch  ;  in  this  course  it  lies  at  first  anterior  to  the  aorta, 
and  afterwards  to  the  left  side.  The  right  pulmonary  artery 
is  the  longer  branch  ;  it  turns  in  a  traverse  direction  to  the 
right  side,  and  passes  through  the  arch  of  the  aorta,  and 
behind  the  superior  cava,  to  the  root  of  the  right  lung,  and 
there  divides  into  three  branches.  The  left  pulmonary  arte- 
ry is  short,  proceeds  to  the  left  side,  and  entering  the  root 
of  the  left  lung  anterior  to  the  left  bronchus,  divides  into 
two  branches ;  from  the  division  of  the  pulmonary  artery 
a  ligamentous  cord  extends  backwards  and  downwards  to 
the  lower  extremity  of  the  arch  of  the  aorta  ;  this  is  the  re- 
mains of  the  ductits  arteriosus,  which  in  the  foetus  convey- 
ed the  blood  from  the  pulmonary  artery  into  the  aorta,  as 
it  could  not  pass  in  -any  quantity  through  the  condensed 
structure  of  the  lungs- ;  the  recurrent,  or  inferior  laryngeal 
nerve  of  the  left  side  winds  round  this  substance.  In 
the  lungs  the  pulmonary  arteries  divide  iiito  numerous 
branches,  which  spread  minutely  on  the  air-cells,  on  which 
they  terminate  in  the  pulmonary  veins,  which  vessels  thus 
arise  by  innumerable  ramifications  ;  these  unite  with  each 
other,  and  form  larger  trunks,  which  arrive  at  the  root  of 
the  lungs,  two  on  each  side,  where  they  lie  anterior  and 


88  DUBLIN    DISSECTOR. 

inferior  to  the  pulmonary  artery  ;  these  veins  then  pass  in- 
wards to  join  the  left  auricle,  a  cavity  which  may  be  next 
examined. 

The  left  auricle  is  situated  at  the  upper  and  back  part  of 
the  heart,  in  front  of  the  mediastinum ;  it  may  be  exposed, 
either  by  raising  the  apex  of  the  heart,  or  removing  this 
organ  from  the  body,  and  placing  it  on  its  anterior  sur- 
face ;  it  is  somewhat  square,  smaller  than  the  right,  but  its 
parietes  are  thicker  and  stronger ;  from  its  upper  and  left 
extremity  its  appendix,  which  is  very  small,  passes  for- 
wards, and  overlaps  the  origin  of  the  pulmonary  artery ; 
lay  open  this  cavity  by  a  perpendicular  incision  along  its 
middle  line;  internally  we  perceive  it  smooth,  except  in 
the  appendix,  where  a  few  fleshy  fasciculi  appear,  as  in 
the  right  side  ;  on  the  septum  auricularum,  a  slight  depres- 
sion, not  so  distinct  as  that  in  the  right  auricle,  marks  the 
former  situation  of  the  foramen  ovale ;  the  four  pulmonary 
veins  are  seen  opening  into  the  angles  of  this  cavity,  two 
on  each  side ;  those  of  the  left  open  very  near  each  other, 
and  sometimes  in  common,  beneath  the  opening  of  the  ap- 
pendix ;  at  its  inferior  part  we  perceive  the  opening  into 
the  left  ventricle,  circular,  smooth  and  marked  by  a  white 
line,  as  in  the  right  auriculo- ventricular  opening,  than 
which  this  of  the  left  side  is  somewhat  smaller.  The  left 
ventricle  is  conical ;  its  apex  forms  the  apex  of  the  heart ; 
flattened  anteriorly,  longer  but  smaller  than  the  right  ven- 
tricle, its  parietes  are  much  thicker,  and  to  it  the  septum 
cordis  appears  to  belong.  Continue  the  incision  that  had 
been  made  in  the  left  auricle  downwards  along  the  back 
of  the  left  ventricle  to  its  apex ;  the  great  thickness  of  its 
walls,  and  the  roughness  of  its  internal  surface  from  the 
strong  and  projecting  carnese  columnse,  may  now  be  re- 
marked ;  at  the  superior  part  of  this  cavity,  we  find  the 
auricular  and  aortic  openings ;  these  lie  very  near  each 
other,  the  arterial  being  immediately  in  front  of  the  auri- 
cular :  from  the  circumference  of  the  latter  there  descends 
a  fold  of  membrane,  which  divides  into  two  portions,  called 
the  mitral  valves ;  these  are  stronger,  but  in  every  other  re- 
spect are  similar  to  the  tricuspid  valves  in  the  right  ven- 
tricle ;  these  also  answer  a  similar  office,  that  of  prevent- 
ing the  blood  returning  from  the  left  auricle.  The  aortic 
opening  is  situated  at  the  upper  and  anterior  part  of  the 
left  ventricle,  in  front  of  the  auricular,  from  which  it  is 
separated  by  the  anterior  or  large  division  of  the  mitral 
valve ;  the  ventricle  is  smooth  in  the  vicinity  of  this  open- 
ing. The  anterior  division  of  the  mitral,  and  the  left  of 
the  tricuspidal  valves  are  supposed  to  be  larger  than  the 
other  portions,  for  the  purpose  of  preventing  any  blood  flow- 


DUBLIN    DISSECTOR.  89 

ing  from  the  auricle  or  ventricle  into  the  aorta  or  pul- 
monary artery,  until  the  ventricle  is  fully  distended.  The 
aorta  arises  from  the  left  ventricle  in  the  same  manner  as 
the  pulmonary  artery  from  the  right ;  three  semilunar 
valves  also  proceed  from  this  orifice  into  the  aorta,  stronger, 
but  similar  in  structure  and  in  function  to  those  in  the  pul- 
monary artery,  the  corpora  Arantii  in  particular  are  larger 
and  firmer  in  the  aortic  valves ;  external  to  each  semilunar 
valve,  the  aorta  is  dilated  into  a  small  sinus ;  these  three 
are  named  the  sinuses  of  Morgagni,  or  lesser  sinuses  of  the 
aorta.  The  aorta  at  its  origin-is  covered  by  the  pulmonary 
artery  ;  it  ascends  obliquely  forwards  and  to  the  right,  as 
high  as  on  a  level  with  the  cartilages  of  the  second  rib  of 
each  side;  it  then  passes  backwards,  and  to  the  left  side; 
and  lastly,  descending  as  low  as  the  fourth  dorsal  vertebra, 
it  becomes  closely  attached  to  the  spine;  this  portion  of 
the  aorta  is  called  the  arch,  at  the, termination  of  which  this 
vessel  receives  the  name  of  thoracic  or  descending  aorta, 
which  descends  through  the  posterior  mediastinum,  as  was 
already  stated ;  the  arch  of  the  aorta  is  divided  into  the  as- 
cending, the  transverse,  and  the  descending;  the  first  is 
the  longest  portion,  and  in  general  is  so  much  dilated  at 
the  upper  part  as  to  have  received  the  name  of  the  great 
sinus;  this  ascending  portion  is  within  the  pericardium, 
covered  at  first  by  the  pulmonary  artery ;  it  afterwards 
lies  between  this  vessel  and  the  vena  cava ;  from  the  com- 
.mencement  of  this,  the  two  coronary  arteries  arise ;  the 
middle  or  transverse  portion  of  the  arch  lies  above  the  peri- 
-cardium,  and  in  front  of  the  trachea ;  from  it  arise  the  in- 
nominata,  left  carotid,  and  left  subclavian ;  the  descending 
.portion  bends  behind  the  root  of  the  left  lung,  and  is  con- 
nected to  the  pulmonary  artery  by  the  remains  of  the 
ductus  arteriosus ;  through  the  arch  of  the  aorta,  the  right 
pulmonary  artery,  left  bronchus  and  'left  'recurrent  nerve 
pass. 

The  heart  is  composed  of  three  tunics ;  first,  the  reflected 
serious  layer  of  the  pericardium,  externally;  second,  the 
serious  membrane  which  lines  the  vascular  system,  inter- 
.nally,  [the  endocardium;]  and.  thirdly,  between  these  mem- 
branes" a  lamina  of  muscular  substance  :  the  serous  mem- 
branes are  stronger,  but  the  muscular  tunic  weaker  in  the 
auricles  than  in  the  ventricles ;  the  muscular  fibres  are 
arranged  chiefly  in  a  spiral  direction,  but  they  are  so 
closely  united  that  their  course  is  not  obvious,  unless  after 
long  maceration  ;  external  to  this  tunic,  in  the  adult  or  old, 
and  on  the  right  side  principally,  we  generally  find  a 
quantity  of  adeps  placed.  The  coats  of  the  heart  are  sup- 
plied with  blood  from  the  two  coronary  arteries,  the  first 

8* 


90  DUBLIN    DISSECTOR. 

branches  of  the  aorta :  the  nerves  of  the  heart  are  small 
and  numerous,  they  are  derived  from  the  cervical  ganglions 
of  the  sympathetic,  and  from  the  pneumogastric  of  each 
side. — (See  Vascular  and  Nervous  Systems.) 

[The  heart  is  of  a  florid  red  color,  in  the  healthy  adult ;  but  be- 
comes paler  in  advanced  life  ;  the  internal  muscular  fibres,  are  usually 
redder  than  the  external,  the  color  however  depends  upon  the  state 
of  the  system.  The  size  of  the  heart  is  about  the  same  as  that  of  the 
fist  of  the  individual,  varying  however  with  disease  ;  in  persons  of 
middle  stature,  or  under,  this  organ  is  absolutely  larger  than  in  very 
tall  people  ;  the  capacity  of  the  auricles  is  greater  than  that  of  the 
ventricles  and  that  of  the  right  cavities,  greater  than  that  of  the  left. 
By  comparing  the  results  obtained  by  several  of  our  best  anatomists 
and  pathologists,  it  is  found  that  the  average  weight  of  the  healthy 
adult  heart,  is  from  eight  to  eight  and  a  half  ounces  ;  the  weight  of 
this  organ  compared  with  that  of  the  body,  is  in  inverse  ratio  to  period 
after  conception.  Thus  at  the  end  of  three  months,  it  is  as  one,  to 
fifty,  at  the  full  time,  as  one  to  one  hundred  and  twenty.  The  average 
length  of  the  heart  from  base  to  apex,  is  five  and  a  half,  to  five  and 
three  quarter  inches,  of  which  about  four  inches  belong  to  the  ventri- 
cles. The  average  circumference,  at  the  auriculo-ventricular  groove, 
is  from  eight  to  nine  inches,  the  breadth  three  arid  a  half  to  four 
inches,  and  the  thickness  about  two  inches.  The  parietes  of  the 
several  cavities  differ  in  thickness,  and  those  of  each  cavity  vary  at 
different  points  ;  it  may  be  stated  in  general  terms,  that  the  average 
thickness  of  the  right  auricle  is  one  line,  of  the  left  auricle  one  line 
and  a  half;  of  the  right  ventricle  two  lines  and  a  half,  and  of  the  left 
ventricle,  from  six  to  seven  lines ;  the  average  thickness  of  the  ven- 
tricular septum,  is  five  lines  and  a  half,  being  however  thicker  at  its 
centre,  and  that  of  the  auricular  septum  is  one  line  and  a  half.  The 
circumference  of  the  aorta,  is  about  two  inches  and  three  quarters  ;  of 
the  pulmonary  artery  three  inches,  or  a  trifle  more,  of  the  left  auriculo 
ventricular  opening,  four  inches,  and  of  the  right  four  inches  and  a  half. 

In  the  foetus  and  infant,  the  position  of  the  heart  is  vertical  instead 
of  oblique,  as  afterwards.  A  porlion  of  the  heart  is  not  overlapped 
by  the  lungs,  this  part  is  behind  the  sternum  a  little  to  the  left  of  the 
median  line,  and  here  the  heart  may  be  examined  by  auscultation  ; 
by  having  the  patient  seated  so  as  to  lean  forward,  the  heart  will  be 
more  completely  projected  against  the  sternum,  and  hence  the  sound 
will  be  more  distinct  than  if  the  patient  is  on  his  back,  as  then  the 
heart  falls  somewhat  towards  the  spine.  The  congenital  malforma- 
tions of  this  organ,  are  numerous,  but  as  in  its  development  it  passes 
through  various  stages,  similar  to  the  normal  development  of  the 
heart,  in  inferior  animals,  so  these  malformations,  for  the  most  part, 
appear  to  depend  upon  an  arrest  of  development,  in  one  or  the  other 
of  these  stages.  Most  of  these  malformations,  are  incompatible  with 
the  prolongation  of  life,  yet  occasionally  we  find  that,  subjects  labor- 
ing under  them  live  for  many  years.  The  heart  is  rarely  entirely 
wanting,  when  this  is  the  case,  there  is  also  an  absence  of  the  brain. 
It  is  always  a  double  organ,  the  two  parts  united  together,  but  some- 
times  there  are  two  hearts,  for  example,  one  case,  where  one  organ 


DUBLIN    DISSECTOR.  91 

was  in  the  thorax  the  other  in  the  abdomen  ;  the  heart  sometimes  in- 
clines  to  the  right  side  instead  of  the  left,  a  case  is  known  to  us,  in 
which  two  members  of  the  same  family  are  thus  formed.  This  mal- 
position is  usually  attended  with  a  transposition  of  other  organs.  A 
remarkable  specimen  of  transposition  has  been  preserved  in  the  Cin- 
cinnatti  medical  college,  and  another,  in  the  medical  department  of 
Yale  college,  both  within  two  years.  The  valves  are  sometimes  de- 
ficient in  number,  sometimes  incomplete,  so  as  not  to  meet  in  the 
centre  of  the  orifices  to  which  they  belong.  Congenital  varieties  in 
the  origins  and  terminations  of  the  larger  vessels,  connected  with  the 
base  of  the  heart  are  not  uncommon.] 

The  heart  is  subject  to  many  diseases,  the  morbid  appear- 
ances of  which  will  be  soon  detected  by  any  person  well 
acquainted  with  its  natural  structure.     Carditis,  or  inflam- 
mation of  its  substance  is  rare,  it  is  usually  confined  to 
some   portion   of  the   organ,  and   pus   is  found  diffused 
amongst  its  fleshy  fibres,  or  sometimes  collected  into  a 
cyst.     Ramollissement,  in  this  case  the  heart  is  sometimes 
so  soft  that  the  finger  can  pass  through  it ;  the  colour  is 
brown  or  deep  red  if  the  change  have  been  recent,  if 
chronic,  pale  and  yellowish  ;  this  affection  sometimes  ends 
in  rupture.    Induration,  is  usually  confined  to  some  por- 
tions of  the  heart  which  will  be  found  so  crisp  as  to  grate 
under  the  knife.     Hypertrophy,  or  enlargement  of  its  cavi- 
ties and  thickening  of  its  parietes ;   this  change  is  most 
common  in  the  left  ventricle.    Atrophy,  or  diminution  of 
the  organ ;  its  fibres  are  pale,  flabby,  and  intermingled 
with  soft  adeps ;  in  this  case  the  cavities  are  not  dimin- 
ished in  size  ;  this  change  is  most  frequent  in  the  right 
ventricle.    Tubercles  are  sometimes  found  in  the  parietes 
of  the  heart,  and  are  very  small.    Sanguineous  concre- 
tions, or  coagula,  incorrectly  called  polypi,  are  common  in 
the  right  cavities,  they  are  usually  free  from  the  colour  of 
the  blood,  and  are  like  a  mass  of  fibrine  ;  in  dropsical  sub- 
jects they  often  appear  gelatinous  and  semi-transparent ; 
when  recent  they  have  no  adhesion,  but  if  long  formed 
they  often  adhere  closely.    The  aortic  and  mitral  valves 
are  often  found  diseased,  on  the  latter  fleshy  vegetations 
frequently  grow,  and  calcareous  matter  is  very  commonly 
deposited  both  in  these  valves  as  well  as  in  the  semilunar 
folds  at  the  aortic  opening.    The  left  auriculo-ventricular 
opening  is  occasionally  so  much  contracted  as  to  embarrass 
the  circulation  very  considerably,  this  function  is  also  oc- 
casionally suspended  by  a  rupture  of  one  of  the  mitral  or 
semilunar  valves :  the  valves  at  the  right  side  of  the  heart 
are  seldom  found  diseased.     Malformation,  or  imperfect 
development,  is  not  uncommon  in  this  organ ;  thus  the  fora- 
men ovale  is  sometimes  open ;  also  a  communication  be- 


!92  DUBLIN    DISSECTOR. 

tween  the  ventricles,  through  their  septum,  occasionally 
exists.  These  conditions  are  usually  attended  with  a  bluish 
tint  of  the  skin  and  other  marks  of  imperfectly  oxygenated 
blood. 

[The  heart  is  sometimes  the  seat  of  a  fatty  transformation,  this  is 
most  common  in  old  subjects  ;  it  is  also  the  seat  of  cartilaginous  and 
osseous  transformations,  but  these  are  rare.  Ossification  is  sometimes 
confined  to  a  few  of  the  muscular  fibres,  sometimes  involves  the 
whole  paries  of  one  cavity,  and  one  case  is  recorded  by  Monro,  in 
which  the  whole  heart  except  the  left  auricle  was  converted  into  bone 
from  the  cases  reported  it  would  seem  that  the  ventricles  are  more 
subject  to  this  change  than  the  auricles  ;  there  are  specimens  of  this 
affection  in  the  college  museum.  Endocarditis  is  an  inflammation 
of  the  lining  membrane  of  the  heart ;  it  is  apt  to  result  in  vegetations 
(probably  fibrine,)  which  .are  most  common  at  the^aertic  and  mitral 
valves,  but  may  occur  in  any  of  the  cavities  of  the  heart ;  this  in 
flammation  may  also  result  in  a  cartilaginous  thickening  or  ossifica- 
tion, which  also  generally  occurs  upon  and  around  the  aortic  and 
mitral  valves,  those  of  the  .right  side,  being  rarely  thus  affected  ;  a 
.pathological  fact  establishing  the  difference  between  the  venous  and 
arterial  membranes,  and  proving  that  the  right  endocardium  is  simi- 
lar to  the  lining  membrane  of  the  veins,  and  the  left,  to'that  of  the 
arteries.  There  is  a  preparation  in  the  college  museum  showing  that 
aneurism  of  the  valves  may  occur ;  in  this  specimen,  one  of  the 
mitral  valves  is  affected.] 

The  student -may  next  examine  what  are  the  parts  which 
'pass  through  the  -upper  orifice  of  the  thorax. 

Posterior 'to  the  deep  cervical  fascia,  we  perceive  the 
sterno-hyoid  and  thyroid  muscles  first  ascending  through 
this  opening :  behind  these  is  a  quantity  of  cellular  mem- 
brane, and  the  remains  of  the  thymus  body  :  next  are  the 
•right  and  left  xencc.  innominate  the  former  descending  per- 
pendicularly, 'the  latter  obliquely  across  this  opening ; 
these  two  veins  unite  opposite  the  cartilage  of  the  second 
rib  of  the  fight  side,  and  'form  the  superior  vena  cava, 
which  soon  enters  the  pericardium,  and  empties  itself  into 
the  right  auricle ;  behind  these  veins,  the  phrenic  and  par 
vagum  enter  the  chest;  the  former  is  external  and  anterioi 
to  the 'latter,  and  both  are  anterior  to  the  subclavian  arte 
ries.  'The  phrenic  nerve,  accompanied  by  the  internal  mam 
mary  vessels,  descends  through  the  thorax,  anterior  tothi. 
root  of  the  lungs,  to  the  rliaphragm,  to  which  it  is  distri 
buted;  this  nerve  on  the  left  side  is  longer,  and  lies  some 
what  posterior  to  that  on  the  right  side  ;  the  eighth  pair  en- 
tering the  chest,  between  the  subclavian  vein  and  artery, 
passes  backwards  behind  the  root  of  the  lung,  on  which  it 
forms  an  extensive  plexus,  pulmonary  plexus  ;  it  then  enters 
the  posterior  mediastinum,  and  becomes  attached  to  the 
oesophagus,  which  conduct  3  it  to  the  stomach.  We  next 


DUBLIN    DISSECTOR.  93 

perceive  the  innominata,  left  carotid,  and  left  subclavian 
arteries  ascending  out  of  this  cavity ;  the  innominata  is 
most  anterior,  and  the  left  subclavian  the  most  posterior 
of  the  three.  The  trachea  is  next  seen  entering  the.  thorax, 
behind  these  vessels,  and  inclining  a  little  to  the  right  side  ; 
this  tube  commences  opposite  the  fifth  or  sixth  cervical 
vertebra,  descends  at  first  in  the  middle  line,  but  as  it  ap- 
proaches the  chest,  it  inclines  to  the  right,  the  aorta  press- 
ing on  its  left  side ;  in  the  neck  it  rests  on  the  oesophagus, 
and  lies  between  the  great  vessels ;  it  is  covered  by  the 
thyroid  body  and  its  veins,  the  sternal  muscles,  the  arteria 
and  left  vena  innominata :  in  the  thorax,  the  trachea  de- 
scends obliquely  backwards,  and  opposite  the  third  dorsal 
vertebra  it  divides  into  the  right  and  left  bronchial  tubes  ; 
a  number  of  dark  lymphatic  ganglia  (the  bronchial  ganglia) 
lie  in  the  angle  of  the  division,  and  adhere  closely  to  the 
branches.  The  trachea  is  composed  of  eighteen  or  twenty 
fibro-cartilages,  connected  together  by  an  elastic  substance, 
and  lined  by  mucous  membrane ;  each  cartilage  forms 
about  three-fourths  of  a  circle,  the  deficiency  posteriorly 
being  filled  by  a  fibrous  membrane,  which  also  encloses 
the  cartilages,  and  by  some  transverse  muscular  fibres  and 
mucous  glands ;  the  right  bronchial  tube  is  the  larger  branch  ; 
it  runs  transversely  into  the  root  of  the  lung,  and  divides 
into  three  branches ;  the  vena  azygos  bends  over  this  ves- 
sel; the  left  bronchial  tube  is  longer,  and  takes  a  course 
slightly  curved  downwards  and  to  the  left  side,  through  the 
arch  of  the  aorta  to  the  root  of  the  left  lung,  and  then  di- 
vides into  two  branches ;  the  further  subdivisions  of  these 
two  tubes  gradually  lose  the  cartilaginous  structure,  divide 
into  numerous  fine  membranous  vessels,  each  of  which  ter- 
minates in  a  cluster  of  small  cells ;  those  in  each  single 
group  communicate  freely,  but  those  of  one  lobule  do  not 
communicate  with  those  in  another,  except  through  the 
medium  of  the  air-tube,  from  which  both  are  derived ;  on 
the  delicate  membrane  composing  these  air  vesicles,  the 
pulmonary  arteries  and  veins  minutely  ramify :  the  bronchi 
are  composed  of  the  same  structures  as  the  trachea,  the. 
cartilages,  however,  soon  lose  their  annular  form,  and  be- 
come irregular ;  in  their  minute  subdivisions  they  no  lon- 
ger exist ;  the  air  serves  to  retain  these  as  well  as  the  cells 
in  a  permanently  distended  condition. 

[The  rings  of  the  trachea,  are  not  apt  to  ossify,  still  this  takes  place 
occasionally,  even  to  such  extent  as  to  involve  the  whole  ring.  The 
bronchial  tubes  are  also  sometimes  ossified.  If  a  small  foreign  body 
passes  down  into  the  trachea,  it  may  be,  and  generally  is  arrested  at 
the  befurcation  ;  if  not  it  passes  by  preference  into  the  right  bronchial 
tube,  after  which,  though  beyond  the  reach  of  the  surgeon,  it  is  some- 


l  'DUBLIN    DISSECTOR. 

times  thrown  off  by  the  efforts  of  nature,  and  the  patient  recovers. 
An  interesting  case  of  this  kind  is  recorded  in  the  Boston  Medical 
and  Surgical  Journal,  in  which  a  nail  passed  into  the  trachea  of  a 
child  ;  the  operation  of  tracheotomy  was  performed,  low  down,  but 
the  nail  had  passed  the  bifurcation  and  was  beyond  reach  ;  the  patient 
recovered  from  the  operation,  but  labored  under  severe  symptoms  for 
some  time,  when  the  nail  was  coughed  up  with  a  quantity  of  pus, 
and  the  child  recovered.  If  the  ear  be  placed  over  the  two  bronchial 
tubes  different  sounds  will  be  detected.] 

Behind  the  tracluea,  the  (Esophagus  «is  seen  entering  the 
thorax,  lying  close  to  the  spine.;  at  first  a  little  to  the  left 
of  the  mesial  line,  afterwards  to  the  right  of  that  line,  and 
as  it  descends  through  the  posterior  mediastinum,  it  again 
inclines  to  the  left.  On  the  left  side  of  this  tube,  the  tho- 
racic duct  is  seen  ascending  from  the  thorax  into  the  neck, 
between  the  left  carotid  .and  subclav.iim  arteries.  As  the 
oesophagus  enters  the  chest,  we  observe  on  either  side  of  it 
the  recurrent  nerve ;  that  of  the  left  side  passes  out  of  this 
-cavity,  that  of  the  right  arises  on  a  level  with  the  opening ; 
external  to  this  nerve,  on  each  side,  we  perceive  the  sympa- 
thetic entering  the  chest ;  it  lies  posterior  to  the  phrenic 
and  the  vagus,  but  between  both  ;  this  nerve  having  .form- 
ed its  inferior  cervical  ganglion,  divides  into  '.several 
branches  which  descend  into  the  thorax,  a  few  pass  ante- 
rior to  the  subclavian  artery,  the  principal  pass  behind  it.; 
•they  all  unite  in.its  fir-wt  thoracic  ganglion,  which  is  situat- 
ed on  the  neck  of  the  h'rst  rib  ;  the  sympathetic  then  de- 
scends along  the  side  of  the  spine,  passing  over  the  heads 
of  the  ribs,  and  opposite  each  intercostal  space  forms  a 
small  triangular  ganglion,  from  each  of  which  two  or  three 
small  branches  proceed  to  join  the  dorsal  spinal  nerves, 
and  from  the  five  or  six  inferior  the  great  and  small  splanch- 
nic nerves  arise;  the  sympathetic  is  so  small,  inferiorly, 
that  it  is  often  difficult  to  trace  it ;  it  escapes  from  the  tho- 
rax into  the  abdomen,  beneath  the  true  ligamentum  arcua- 
tum.  Posterior  to  the  oesophagus,  the  longi  colli  muscles 
ascend  through  the  upper  opening  of  the  thorax  ;  on  each 
side  of  these  lie  the  superior  intercostal  artery,  and  the  an- 
terior branch  of  the  first  dorsal  nerve,  ascending  to  join  the 
last  cervical  in  the  brachial  plexus. 


DUBLIN    DISSECTOR,-  95- 


CHAPTER   IV. 

MUSCLES  OF  THE  BACK. 
SECTION  I. 

PLACE  the  subject  on  the  forepart,  raise  the  chest  by 
blocks,  let  the  head  and  arms  hang ;  thus,  the  muscles  in 
this  region  will  be  made  tense  :  divide  the  integuments 
along  the  middle  line,  from  the  occiput  to  the  sacrum ; 
make  a  transverse  incision  from  the  last  cervical  vertebra 
to  the  acromion,  and  another  from  the  last  dorsal  vertebra 
to  the  posterior  part  of  the  axilla ;  reflect  the  upper  and 
lower  flap  of  integument  from  the  spine  towards  the  side,, 
and  raise  the  middle  portion  from  below  upwards  and  out- 
wards ;  thus  the  dissector  can  more  easily  expose  the  tra- 
pezius  and  latissimus  dorsi  muscles ;  the  integuments  in 
this  region  are  dense,  also  the  subjacent  cellular  tissue, 
which  seldom  contains  much  adeps  mr  interiorly  it  is  often 
anasarcous ;  when  all  this  is  dissected,  from  the  posterior 
part  of  the  trunk,  we  see  exposed  the  trapezius  superiorly,, 
the  latissimus  dorsi  inferiorly,  and'  between  these,  in  a 
small  triangular  space  behind  the  base  of  the  scapula,  a 
part  of  the  great  rhomboid,  also  two  or  three  tendons  of 
the  sacro-lumbalis,  and  a  portion  of  the  seventh,  eighth, 
and  ninth  ribs,  and  of  the  corresponding  intercostal  mus- 
cles ;  along  the  middle  line  of  the  neck,  a  strong  ligament 
is  observed,  (ligamcntum  nuchse),.  at  the  lower  part  of 
which  is  a  strong  aponeurosis  of  an  oval  form,,  (the  cervi- 
cal aponeurosis)  :  also  covering  the  lumbar  region  another 
still  stronger  is  seen,,  (the  lumbar  fascia). :  to  each  of  these 
the  student  should  pay  attention.  The  ligamentumnuch(C  is 
inserted  superiorly  into  the  occipital  protuberance,  it  de- 
scends in  the  median  line,  broad  above,  and  sinking  in 
deep,  so  as  to  form  a  septum:  between  the  muscles  on  the 
right  and  left  sides,  and  is  inserted  inferiorly  into  the  spi- 
nous  processes  of  the  three  or  four  last  cervical  vertebrae, 
and  into  the  cervical  aponeurosis.  Use,,  to  support  the 
head  in  flexion  of  the  neck,  and  to  give  attachment  to  mus- 
cles. The  cervical  aponeurosis  extends  from  the  fifth  cervi- 
cal to  the  fifth  dorsal  vertebra,  narrow  at  each  extremity, 
and  broad  in  the  centre  between  the  superior  angles  of  the 
two  scapulse ;  the  fibres  are  transverse,  and  continuous 
with  the  fibres  of  the  trapezium  on  each  side ;  it  gives 
strength  to  these,  and  binds  down  the  subjacent  muscles,. 


96  DUBLIN    DISSECTOR. 

The  lumbar  fascia  is  of  great  strength  ;  it  is  also  somewhat 
oval,  attached  by  its  interior  extremity  to  the  spinous  pro- 
cesses of  the  sacrum,  and  by  its  superior  to  those  of  the  in- 
ferior dorsal  vertebrae ;  on  either  side  it  is  connected  to  the 
crest  of  the  ilium,  and  to  the  abdominal  muscles,  particu- 
larly to  the  transversal  is,  also  to  the  latissimus  dorsi  and 
serratus  posticus  inferior ;  its  internal  surface  is  attached 
along  the  median  line  to  the  spines  of  the  lumbar  verte- 
brae, and  on  either  side  to  the  traverse  processes.  In  the 
course  of  the  dissection  of  the  lumbar  muscles,  this  fascia 
will  be  found  to  consist  of  three  lamina?,  the  first,  or  pos- 
terior, that  which  is  seen  at  present,  is  attached  to  the 
spines  of  the  lower  dorsal  and  to  those  of  all  the  lumbar 
vertebras  and  sacrum,  it  gives  attachment  to  the  latissimus 
dorsi,  serratus  posticus  inferior,  obliquus  internus,  and 
transversalis  abdominis  muscles.  The  second  or  middle 
layer  is  attached  to  the  transverse  processes  of  the  lumbar 
vertebrae,  and  lies  posterior  to  the  quadratus  lumborum 
muscle ;  and  the  third  or  anterior  layer  is  in  front  of  the 
quadratus  and  psoas  muscles,  and  is  attached  to  the  sides 
of  the  bodies  of  the  lumbar  vertebras.  This  fascia  gives 
great  support  to  the  loins,  where  the  skeleton  is  compara- 
tively weak ;  like  the  ligamentum  nuchae  it  supports  the 
trunk  in  flexion,  it  also  assists  in  maintaining  it  in  equili- 
bria in  lateral  motion,  and  it  also  serves  to  give  attachment 
to  several  muscles,  which,  again  in  their  turn,  serve  to  keep 
it  in  a  state  of  tension. 

The  muscles  of  the  back  are  many  of  them  indistinct, 
and  vary  very  much  in  different  subjects  both  in  their  ap- 
pearance and  in  their  exact  attachments  to  any  certain 
number  of  vertebrae  ;  the  student  is  not  to  expect  therefore 
to  find  each  muscle  in  this  region  to  correspond  accurately 
with  the  description  that  is  given,  some  being  attached  to 
a  greater,  others  to  a  less  number  of  processes  than  is 
stated.  The  muscles  of  the  back  are  arranged  in  four  suc- 
cessive layers,  each  nearly  covering  the  other  between  the 
integuments  and  the  bones  ;  the  muscles  of  the  first  layer 
are  two  in  number,  viz.  the  trapezius  and  the  latissimus 
dorsi. 

TRAPEZIUS,  broad,  triangular,  the  base  along  the  spine, 
the  apex  at  the  shoulder,  arises  by  a  thin  aponeurosis  from 
the  internal  third  of  the  superior  transverse  ridge  of  the  oc- 
cipital bone,  from  the  ligamentum  nuchae,  and  from  the 
spinous  processes  of  the  last  cervical,  and  of  all  the  dor- 
sal vertebrae ;  the  superior  fibres  descend  obliquely  out- 
wards and  forwards ;  the  middle  pass  transversely,  the  in- 
ferior ascend  obliquely  forwards;  all  converge  towards 
the  shoulder,  and  are  inserted  into  the  posterior  border  of 


DUBLIN    DISSECTOR.  97 

the  external  third  of  the  clavicle,  and  of  the  acromion  pro- 
cess, also  into  the  upper  edge  of  the  spine  of  the  scapula. 
Use,  to  raise  and  draw  backwards  the  shoulder ;  the  infe- 
rior fibres  which  end  in  a  triangular  shaped  tendon,  which 
glides  over  the  triangular  smooth  surface  at  the  commence- 
ment of  the  spine,  may  draw  down  the  base  of  the  scapula, 
and  thus  by  rotating  this  bone  will  elevate  the  acromion 
process,  and  assist  the  remainder  of  the  muscle  in  raising 
the  shoulder;  the  trapezius  may  also  incline  the  head 
backwards  and  to  one  side.  This  muscle  is  covered  by 
the  skin  only,  its  origin  in  many  points  is  continuous  with 
that  of  its  fellow;  it  covers  the  splenii,  complexi,  serratus 
superior,  levator  scapula?  and  rhomboid  muscles ;  its  an- 
terior fibres  are  parallel  to  the  sterno-mastoid,  in  contact 
with  it  above,  but  separated  below,  by  fat,  vessels  and 
nerves ;  in  some  subjects  a  band  of  fleshy  fibres  unites 
these  muscles  above  the  clavicle. 

[Variety.  The  origins  from  the  three  or  four  lower  dorsal  vertebrse 
are  sometimes  wanting  ;  also  the  lower  part  of  the  muscle,  is  some, 
times  separated  from  the  rest  by  a  large  triangular  space.] 

LATISSIMUS  DORSI  is  very  broad,  and  also  triangular ;  it 
covers  the  greater  part  of  the  lumbar  and  dorsal  regions, 
and  extends  from  these  to  the  inner  side  of  the  arm  ;  arises 
from  the  six  inferior  dorsal  spines,  and  by  the  lumbar  fas- 
cia from  all  the  lumbar  spines ;  also  from  the  back  of  the 
sacrum,  from  the  posterior  third  of  the  crest  of  the  ilium, 
and  by  distinct  fleshy  slips  from  the  three  or  four  last  ribs 
near  their  anterior  extremity  ;  the  iliac  and  lumbar  fibres 
ascend  obliquely  outwards;  the  dorsal,  which  are  much 
weaker,  pass  transversely ;  and  the  costal  are  nearly  ver- 
tical ;  all  converge  towards  the  inferior  angle  of  the  scapu- 
la, over  which  they  glide,  and  from  which  they  often  de- 
rive an  additional  fasciculus  of  fleshy  fibres ;  thence  the 
muscle  continues  to  ascend  obliquely  outwards  over  the 
teres  major,  and  near  the  inside  of  the  arm  it  twists  beneath 
this  muscle  to  its  forepart,  ends  in  a  flat  broad  tendon, 
which  is  closely  connected  to  that  of  the  teres,  and  is  in- 
serted into  the  inner  or  posterior  edge  of  the  bicipital  groove, 
anterior  and  superior  to  that  tendon  ;  a  small  bursa  is  usu- 
ally found  between  these  tendons  in  this  situation.  Use, 
to  depress  the  shoulder  and  arm,  to  draw  the  arm  back- 
wards and  inwards,  to  rotate  the  humerus  inwards,  so  as 
turn  the  palm  of  the  hand  backwards,  also  to  depress  tho 
ribs  as  in  expiration  ;  but  if  the  upper  extremity  be  raised 
and  fixed,  this  muscle  may  elevate  the  ribs,  and  so  assist 
in  inspiration,  as  well  as  in  raising  the  whole  body,  as  in 
climbing. 

9 


98  DUBLIN    DISSECTOR. 

The  dorsal  portion  of  the  latissimus  dorsi  is  covered  by 
the  trapezius  ;  the  remainder  of  this  muscle  is  superficial, 
its  origin  is  superior  to  the  glutaeus  maximus,  its  anterior 
edge  is  connected  to  the  abdominal  muscles,  the  inferior 
fasciculi  of  the  external  oblique  indigitate  with  its  costal 
origins  ;  it  covers  the  serratus  inferior,  the  lumbar  muscles, 
and  the  angle  of  the  scapula  ;  its  humeral  end  forms  the 
posterior  fold  of  the  axilla ;  a  fasciculus  of  fleshy  fibres 
sometimes  passes  across  the  floor  of  this  region,  and  con- 
nects the  latissimus  to  the  great  pectoral  muscle  ;  between 
the  angle  of  the  scapula  and  the  humerus  this  muscle  has 
a  twisted  appearance,  the  lumbar  and  costal  fibres  being 
inserted  into  the  upper  part  of  the  tendon,  and  the  superior 
or  dorsal  portion  into  its  inferior  edge ;  the  axillary  vessels 
and  nerves  lie  on  this  tendon  at  its  insertion,  and  the  bici- 
pital  groove  is  lined  by  aponeurotic  fibres  derived  from  it, 
and  from  the  tendon  of  the  great  pectoral,  which  are  thus 
united  to  each  other,  although  previous  to  this  they  are 
separated  by  the  brachial  vessels  and  nerves,  and  by  the 
coraco-brachialis  and  biceps  muscles. 

[Another  variety,  in  this  muscle  is,  lhat  a  fasciculus  comes  off 
from  it,  is  connected  to  the  coraco  brachialis,  and  then  inserted  into 
the  coracoid  process  of  the  scapula.] 

Divide  the  trapezius  and  latissimus  longitudinally  be- 
tween the  spine  and  the  scapula,  reflect  one  portion  to- 
wards the  vertebrae,  the  other  towards  the  side,  and  the  se- 
cond layer  of  the  dorsal  muscles  will  be  exposed.  (In  dis- 
secting off  the  latissimus  take  care  not  to  injure  the  serra- 
tus inferior,  which  is  very  thin  and  adheres  closely  to  it.) 

The  second  layer  of  muscles  consists  of  the  rhomboid, 
levator  anguli  scapula?,  serratus  inferior  and  superior,  and 
the  splenii ;  a  considerable  portion  of  each  of  these  is  now 
seen,  although  they  partly  conceal  each  other. 

RHOMBOIDEUS  is  broad,  thin  and  the  most  superficial  of 
this  layer ;  it  is  divided  into  a  superior  or  minor  portion, 
and  an  inferior  or  major  ;  the  minor  arises  from  the  lower 
part  of  the  ligameritum  nuchse,  and  from  the  two  last  cer- 
vical spinous  processes ;  the  fibres  run  parallel  outwards 
and  a  little  downwards  and  are  inserted  into  the  base  of  the 
scapula,  opposite  to  and  above  the  spine.  The  major  arises 
from  the  four  or  five  superior  dorsal  spines  ;  the  fibres  pass 
outwards  and  downwards,  parallel  to  the  former,  and  are 
inserted  into  the  base  of  the  scapula,  extending  from  the 
spine  to  the  inferior  angle.  Use,  to  draw  the  shoulder 
backwards  and  upwards ;  the  inferior  fibres  also  can,  by 
pulling  back  the  inferior  angle,  rotate  the  scapula  so  as  to 
depress  the  acromion  process,  thereby  assisting  the  levator 
anguli  and  the  pectoralis  minor  muscles.  The  rhomboid 


DUBLIN    DISSECTOR,  99 

muscles  are  covered  by  the  trapezius  and  latissiinus,  a  por- 
tion of  the  major  between  these  muscles  is  covered  only  by 
the  integuments,  they  conceal  part  of  the  serrati  postici 
muscles. 

LEVATOR  ANGULI  SCAPULA,  long,  and  somewhat  round, 
placed  at  the  upper  and  posterior  part  of  the  side  of  the 
neck,  arises  by  four  or  five  tendons  from  the  posterior  tu- 
bercles, of  the  transverse  processes  of  the  four  or  five  su- 
perior cervical  vertebrae ;  these  soon  terminate  in  a  fleshy 
belly,  which  descends  obliquely  outwards  and  backwards, 
and  is  inserted  into  the  base  of  the  scapula,  between  the 
spine  and  superior  angle ;  its  use  is  to  elevate  the  whole 
scapula,  if  assisted  by  the  trapezius,  or  to  elevate  the  su- 
perior angle  alone,  and  to  rotate  the  scapular  so  as  to  de- 
press the  acromion,  thus  co-operating  with  the  lesser  pec- 
toral muscle  ;  it  is  covered  by  the  trapezius ;  a  small  por- 
tion may  be  seen  superiorly  between  this  and  the  sterno- 
mastoid  muscle  :  the  tendinous  origins  have  those  of  the 
splenius  colli  behind  them,  and  of  the  scaleni  and  rectus 
capitis  anticus  major  before  them.  Divide  and  reflect  the 
rhomboid  muscles ;  beneath  these  a  quantity  of  loose  cel- 
lular membrane  is  placed,  between  them  and  the  serratus 
magnus,  to  the  posterior  vie.w  of  which  muscle  the  student 
should  now  attend ;  he  may  therefore  again  peruse  the  ac- 
count given  of  that  muscle",  (sec  page  69.) 

SERRATUS  POSTICUS  SUPERIOR,  arises  by  a  thin  aponeuro- 
sis  from  the  ligamentum  nuchse,  and  from  two  or  three 
dorsal  spines,  forms  a  thin  fleshy  belly,  which  ends  in, 
three  fleshy  slips,  which  are  inserted  into  the  second,  third, 
and  fourth  ribs  external  to  their  angles.  Use,  to  expand 
the  thorax  by  elevating  the  ribs  and  drawing  them  out- 
wards. This  muscle  is  covered  by  the  trapezius  and  rhom- 
boid ;  it  lies  on  the  splenius  and  the  deep  layer  of  muscles : 
an  aponeurosis  is  continued  from  it  to  the  inferior  serratus. 

SERRATUS  POSTICUS  INFERIOR,  arises  by  a  thin  tendinous 
expansion,  which  is  connected  through  the  lumbar  fascia 
to  the  two  last  dorsal  and  two  upper  lumbar  spines;  it 
forms  a  thin  fleshy  expansion,  which  divides  into  three  or 
four  fasciculi,  which  are  inserted  into  the  lower  edges  of  the 
four  inferior  ribs  anterior  to  their  angles.  Use :  by  depress- 
ing the  ribs  it  assists  the  abdominal  muscles  in  expiration; 
also,  by  fixing  the  lower  ribs  it  increases  the  power  of  the 
diaphragm,  and  by  aiding  this  muscle  in  enlarging  the 
thorax  it  assists  in  inspiration;  the  two  serrati  also,  by  mak- 
ing tense  the  aponeurosis  which  connects  them  to  each 
other,  compress  and  support  the  deep  muscles  in  this  re- 
gion. The  serratus  postieus  lies  under  the  middle  of  the 
latissimus  dorsi,  to  whose  tendon  it  adheres  intimately,  but 


100  DUBLIN    DISSECTOR. 

can  be  separated  from  it  by  cautious  dissection :  its  attach- 
ment to  the  ribs  is  behind  those  of  the  external  oblique  and 
latissimus  dorsi  muscles.  Reflect  from  its  origin  the  su- 
perior serratus,  and  we  shall  see  the  following  muscle. 

SPLENIUS,  is  long  and  flat,  fleshy  and  tendinous,  lying 
beneath  the  trapezius,  and  extending  in  an  oblique  direc- 
tion from  below,  upwards,  forwards  and  outwards  ;  it  is  di- 
vided into  two  portions,  the  inferior,  or  splenius  colli,  and 
the  superior  or  splenius  capitis.  The  splenius  colli  arises 
from  the  spines  of  the  third,  fourth,  fifth,  and  sixth  dorsal, 
ascends  obliquely  outwards,  and  is  inserted  by  distinct  ten- 
dons into  the  transverse  processes  of  the  three  or  four  su- 
perior cervical  vertebrae  behind  the  origins  of  the  levator 
scapulae.  Use,  to  bend  the  neck  backwards,  and  to  one 
side,  Splenius  capitis  is  larger  than  the  last,  superior  and 
internal  to  which  it  lies ;  it  arises  from  the  spinous  process- 
es of  the  two  superior  dorsal  and  three  inferior  cervical 
vertebras,  and  from  the  ligamentum  nucha? ;  it  ascends  a 
little  obliquely  outwards,  and  becoming  larger,  is  inserted 
into  the  back  part  of  the  mastoid  process,  overlapping  the 
sterno-mastoid,  and  into  the  occipital  bone,  below  the  su- 
perior transverse  ridge.  Use,  to  bend  back  the  head,  and 
when  one  only  acts  to  turn  the  head  to  that  side ;  thus 
cooperating  with  the  stern o-mastoid  of  the  opposite  side. 

The  splenii  capitis  muscles  diverge  superiorly,  and  the 
complexi  which  converge  appear  between  them.  Detach 
the  splenii  from  the  spinous  processes,  and  divide  the  fascia 
lumborum,  and  the  next  layer  of  muscles  will  appear ;  this 
consists  of  the  sacro-lumbalis,  longissimus  dorsi,  and  spi- 
nalis  dorsi,  cervicalis  descendens,  transversalis  colli,  trach- 
elo-mastoideus  and  complexus. 

SACRO-LUMBALIS,  LONGISSIMUS  DORSI,  and  SPINALIS  DORSI, 
these  three  muscles  are  so  closely  connected  inferiorly  as 
to  appear  but  one  mass,  and  several  fibres  must  be  divided 
in  order  to  separate  them  from  each  other ;  they  fill  the 
hollow  between  the  angles  of  the  ribs  and  the  spinous  pro- 
cesses, the  sacro-lumbalis  is  external,  the  longissimus  dorsi 
in  the  middle,  and  the  spinalis  dorsi  is  internal.  Sacro- 
lumbalis  is  the  largest  of  the  three  ;  it  arises  from  the  pos- 
terior third  of  the  crest  of  the  ilium,  from  the  oblique  and 
transverse  processes  of  the  sacrum,  from  the  sacro-iliac 
ligaments,  and  from  the  transverse  and  oblique  processes 
of  the  lumbar  vertebrae;  it  ascends  and  divides  into  several 
long  tendons,  which  are  inserted  into  all  the  ribs  near  their 
angles.  Use,  to  extend  the  spine,  and  bend  it  a  little  to  one 
side,  also  to  depress  the  ribs  as  in  expiration.  The  longis- 
simus dorsi  lies  internal  to  the  last,  and  arises  in  common 
with  it,  from  the  posterior  surface  of  the  sacrum,  and  of 


DUBLIN    BISECTOR.  101 

the  transverse  and  oblique  processes  of  the  lumbar  verte- 
brae ;  ascending  along  the  vertebral  column,  it  is  inserted 
internally  by  small  tendons  into  all  the  dorsal  vertebrae, 
and  externally  by  fleshy  and  tendinous  slips  into  all  the 
ribs  between  their  tubercles  and  angles.  Use,  to  extend, 
bend  to  one  side,  and  support  the  spinal  column.  When 
we  separate  the  sacro-lumbalis  from  the  longissimus  dorsi 
and  evert  the  former,  we  shall  expose  five  or  six  small  ten- 
dinous and  fleshy  fasciculi  which  arise  from  the  superior 
edge  of  each  rib,  and  ascending  are  inserted  into  the  tendons 
of  the  sacro-lumbalis ;  these  are  called  the  musculi  acces- 
sorii;  they  are  very  irregular  in  number,  structure,  and 
size.  Spinalis  dorsi  lies  between  the  longissimus  dorsi  and 
spine ;  it  arises  from  the  two  superior  lumbar  and  three  in- 
ferior dorsal  spines  ;  it  ascends  close  to  the  spinal  column, 
and  is  inserted  into  the  nine  superior  dorsal  spines :  its  use 
is  similar  to  the  last  These  three  muscles  are  covered  by 
the  lumbar  fascia,  and  by  the  two  preceding  layers.  These 
lumbar  muscles  in  old  subjects  will  be  often  found  soft, 
weak,  and  pale,  and  often  blended  with  a  soft  fatty  sub- 
stance, so  as  sometimes  to  resemble  a  mass  of  adipocere. 

CERVICALIS  DESCENDENS,  or  more  properly  ASCENDENS, 
looks  like  a  continuation  of  the  sacro-lumbalis,  internal  to 
which  it  arises  by  four  or  five  tendons  from  as  many  of  the 
superior  ribs  between  their  tubercles  and  angles;  these 
unite  in  a  small  fleshy  belly,  which  ascends  obliquely  for- 
wards and  outwards,  and  is  inserted  by  three  or  four  tendons 
into  the  transverse  processes  of  the  4th,  5th,  and  6th  cer- 
vical vertebras,  between  the  splenius  colli  and  levator 
scapulae.  Use,  to  extend  the  neck,  and  incline  or  turn  it  to 
one  side ;  it  may  also  assist  in  inspiration  by  elevating  the 
ribs. 

TRANSVERSALIS  COLLI,  appears  as  a  prolongation  of  the 
longissimus  dorsi,  internal  to  which  it  arises  by  small  ten- 
dinous and  fleshy  slips  from  the  transverse  processes  of 
five  or  six  superior  dorsal  vertebrae  ;  the  fibres  uniting  as- 
cend obliquely  outwards  and  forwards,  and  are  inserted  by 
small  tendons  into  the  transverse  processes  of  three  or  four 
inferior  cervical  vertebrae,  between  the  cervicalis  descend- 
ens  and  the  trachelo-mastoideus  ;  its  use  is  nearly  similar 
to  that  of  the  last  described  musele. 

TRACHELO-MASTOIDEUS  lies  internal  to  the  last,  and  exter- 
nal to  the  complexus ;  it  arises  by  several  tendinous  bands 
from  the  transverse  processes  of  three  or  four  superior  dor- 
sal vertebrae,  and  from  as  many  inferior  cervical ;  ascend- 
ing a  little  outward  it  is  inserted  into  the  inner  and  back 
part  of  the  mastoid  process,  beneath  the  insertion  of  the 
splenius.  Use,  to  assist  in  extending  the  neck,  to  bring 
9* 


.10fc  PURLIN    DISSECTOR. 

the  head  backwards,  and  to  incline  and  rotate  it  to  one 
side.  This  muscle  is  covered  by  the  splenius  and  trans- 
versalis,  it  lies  upon  the  complexus,  the  obliqui  capitis,  and 
the  digastric  muscles. 

COMPLEXUS  arises  from  the  transverse  and  oblique  pro- 
cesses of  three  or  four  inferior  cervical,  and  five  or  six  su- 
perior dorsal  vertebrae,  internal  to  the  transversalis  and 
trachelo-mastoideus ;  it  forms  a  very  thick  muscle  inter- 
sected by  many  tendinous  bands ;  it  ascends  a  little  in- 
wards, and  is  inserted  close  to  its  fellow  into  the  occipital 
bone,  between  the  two  transverse  ridges.  Use,  to  draw 
back  the  head,  to  fix  and  support  it  on  the  spine,  also  to 
rotate  it,  being,  in  this  action,  an  antagonist  to  the  spleni- 
us, and  an  auxiliary  to  the  sterno-mastoid  of  its  own  side. 
The  complexus  is  concealed  by  the  trapezius  and  spleni- 
us ;  its  insertion,  which  is  covered  by  the  former  only,  can 
be  felt  and  seen  through  the  integuments ;  it  lies  on  the 
semi-spinalis  colli,  the  deep  cervical  artery,  and  the  small 
oblique  and  recti  muscles.  Detach  the  complexus  from 
the  spine  and  reflect  it  towards  the  occiput,  and  evert 
towards  the  ribs  the  other  muscles  of  this  layer,  we  shall 
thus  expose  the  fourth  layer  of  the  dorsal  muscles,  which 
consists  of  the  spinalis  or  semi-spinalis  colli,  the  semi- 
spinalis  dorsi,  multifidus  spinae,  inter-spinales,  inter-trans- 
versales,  and  immediately  below  the  occupit,  the  recti, 
postici,  major  and  minor,  and  obliqui  capitis,  superior  and 
inferior. 

SPINALIS,  or  SEMI-SPINALIS  COLLI,  is  one  of  the  largest 
muscles  in  this  region  ;  it  arises  from  the  extremity  of  the 
transverse  processes  of  five  or  six  superior  dorsal  vertebrae, 
ascends  obliquely  inwards  close  to  the  spine,  and  is  insert- 
ed by  four  heads  into  the  spinous  processes  of  the  second, 
third,  fourth,  and  fifth  cervical  vertebras.  Use,  to  extend 
the  neck  and  incline  it  a  little  to  its  own  side :  this  thick 
muscle  fills  up  the  space  between  the  spinous  and  trans- 
verse processes  of  the  cervical  and  dorsal  vertebra? ;  it  lies 
external  to  the  semi-spinalis  dorsi,  is  overlapped  by  the 
longissimus  dorsi  inferiorly,  the  complexus  superiorly,  and 
the  serratus  posticus  superior,  in  the  middle. 

SEMI-SPINALIS  DORSI  is  similar  to  the  last  muscle  in  form 
and  attachment ;  indeed  they  appear  as  one  long  muscle, 
which  has  been  thus  rather  unnecessarily  divided  into  two, 
each  named  from  the  situation  of  its  principal  portion  ;  it 
arises  by  five  or  six  tendons  from  the  transverse  processes  of 
the  dorsal  vertebrae,  from  the  fifth  to  the  eleventh  ;  its  fibres 
ascend  obliquely  inwards,  and  are  inserted  by  five  or  six 
tendons  into  the  spinous  processes  of  two  inferior  cervical, 
and  three  or  four  superior  dorsal  vertebrae.  Use,  co-oper- 


DUBLIN    DISSECTOR.  103 

ates  with  the  last  described  muscle,  in  extending  the  neck, 
supporting  the  trunk,  and  inclining  the  spine  backwards, 
and  to  one  side  :  it  is  situated  close  to  the  spine  above, 
and  internal  to  the  last  muscle ;  but  below,  it  lies  on  the 
outer  side  of  the  spinalis  dorsi, 

MULTIFIDUS  SPINJE  is  close  to  the  vertebrae,  between  the 
spinous  and  transverse  processes,  and  is  covered  by  the 
two  last  described  muscles ;  it  consist  of  a  series  of  small 
tendinous  and  fleshy  fasciculi ;  theirs*  arises  from  the  spine 
of  the  dentatas,  or  second  vertebrae,  and  descending  ob- 
liquely outwards,  is  inserted  into  the  transverse  process 
of  the  third :  thus  the  succeeding  muscles  are  attached, 
running  obliquely  from  vertebra  to  vertebra  between 
their  spinous  and  transverse  processes ;  some  fasciculi  ex- 
tend over  two  or  three  vertebrae ;  the  last  arises  from  the 
spine  of  the  last  lumbar  vertebras,  and  is  inserted  into  the 
false  transverse  process  of  the  sacrum.  Use,  to  support 
the  spinal  column,  extend  it,  and  incline  it  to  one  side, 
also  to  rotate  one  bone  upon  the  other,  as  far  as  their  articu- 
lating surface  will  admit. 

INTER-SPJNALES  are  short  muscles,  consisting  of  longi- 
tudinal fibres;  their  name  expresses  their  situation  and 
attachment ;  between  the  cervical  spines  they  are  more  dis- 
tinct, and  appear  to  be  in  pairs,  right  and  left,  as  the  spinous 
processes  here  are  forked  ;  some  fibres  in  the  neck  deserve 
the  name  of  supra-spinous  muscles,  as  they  pass  over  these 
processes,  cover  and  adhere  to  several  of  them ;  in  the 
back  they  are  very  indistinct,  almost  wanting,  and  in  the 
loins  they  are  much  weaker  than  in  the  neck,  chiefly  con- 
sisting of  ligamentous  fibres,  with  a  few  muscular  inter- 
mixed. Use,  to  support  and  extend  the  spine. 

INTER-TRANSVERSALES  consist  of  longitudinal  fibres  at- 
tached and  situated,  as  their  name  implies ;  between  the 
cervical  vertebra?  these  muscles  are  more  strong  and  dis- 
tinct, and  consist  of  two  planes,  an  anterior  and  posterior  ; 
between  the  lumbar  vertebras  they  are  less  distinct ;  and 
still  less  so,  indeed  often  wanting,  between  the  dorsal.  Use, 
to  support  the  spine  on  either  side,  and  to  bend  it  laterally. 
External  to  these  in  the  back,  the  levatores  costarum  mus- 
cles are  seen,  which  have  been  already  noticed  in  the  de- 
scription of  the  intercostals.  Between  the  occiput  and  the 
first  and  second  vertebras,  the  following  four  pair  of  mus- 
cles are  situated. 

RECTUS  CAPITIS  POSTICTJS  MAJOR.  Triangular  ;  arises  nar- 
row from  the  spinous  process  of  the  second  vertebra ;  as- 
cends outwards,  and  is  inserted  broad  into  the  inferior  trans- 
verse ridge  of  the  occipital  bone.  Use,  to  extend  the  head, 
or  draw  it  backwards,  also  to  rotate  it  and  the  atlas  on  the 


104  DUBLIN    DISSECTOR. 

dentatas,  co-operating  with  the  splenius  of  the  same  side ; 
this  muscle  is  situated  obliquely  between  the  occiput  and 
the  second  vertebra ;  it  is  covered  by  the  complexus ;  its 
insertion  is  overlapped  by  that  of  the  superior  oblique. 

RECTUS  CAPITIS  POSTICUS  MINOK,  also  triangular,  arises 
narrow  from  the  posterior  part  of  the  atlas ;  passes  up- 
wards, outwards,  and  backwards,  and  is  inserted  broad  into 
the  occipital  bone,  behind  the  foramen  magnum.  Use,  to 
assist  the  former  in  drawing  back  the  head,  and  steadying 
it  on  the  spine ;  this  pair  is  partly  covered  by  the  last  mus- 
cles ;  a  portion  of  them,  however,  is  seen  between  these  : 
both  the  recti  resemble  the  continuation  of  the  inter-spinous 
muscles. 

OBLIQUUS  CAPITIS  INFERIOR,  is  the  strongest  of  these  small 
muscles ;  it  arises  inferior  and  external  to  the  posterior 
rectus,  and  superior  to  the  spinalis  colli,  from  the  spinous 
process  of  the  second  vertebra,  ascends  obliquely  back- 
wards and  outwards,  and  is  inserted  into  the  extremity  of 
the  transverse  process  of  the  atlas.  Use,  to  rotate  the  head 
and  atlas  on  the  second  vertebra,  co-operating  with  the 
splenius  of  the  same  side,  and  the  sterno-mastoid  of  the 
opposite  side:  this  muscle  is  covered  by  the  complexus, 
trachelo-mastoideus,  and  trapezius. 

OBLIQUUS  CAPITIS  SUPERIOR,  smaller  than  the  last,  above 
the  insertion  of  which  it  arises,  narrow,  from  the  upper 
port  of  the  transverse  process  of  the  atlas,  ascends  ob- 
liquely inwards,  overlapping  the  rectus,  and  is  inserted 
broad  into  the  occipital  bone,  between  its  transverse  ridges, 
just  behind  the  mastoid  process.  Use,  to  bend  the  head  to 
one  side,  and  to  draw  it  a  little  backwards ;  it  cannot  have 
any  rotatory  power,  as  there  is  no  rotation  between  the 
occipital  condyles  and  the  atlas.  In  the  dissection  of  the 
muscles  of  this  region,  but  few  vessels  or  nerves  of  size  or 
note  are  met  with ;  the  arteries  which  supply  these  mus- 
cles are  branches  of  the  occipital  and  deep  cervical  supe- 
riorly; the  posterior  branches  of  the  intercostals  in  the 
middle,  and  of  the  lumbar  arteries  below.  The  veins  ac- 
company the  arteries  and  join  the  nearest  venous  trunks. 
The  nerves  are  the  small  posterior  branches  of  the  cervi- 
cal, dorsal,  and  lumbar  spinal  nerves. 


DUBLIN    DISSECTOR.  105 

CHAPTER  V. 

DISSECTION    OF    THE    UPPER    EXTREMITY. 

THE  upper  extremity  is  connected  to  the  trunk  by  the 
sterno-clavicular  ligaments,  and  by  ten  muscles,  of  which 
one  is  connected  to  the  clavicle,  (subclavius,)  two  to  the 
humerus,  (pectoralis  major  and  latissimus  dorsi,)  and  eight 
to  the  scapula — viz.,  trapezius,  levator  anguli  scapulae,  omo~ 
hyoid,  rhomboid  major  and  minor,  serratus  magnus,  pec- 
toralis minor,  and  latissimus  dorsi ;  this  last  is  also  inserted 
into  the  humerus  ;  all  these  muscles  have  been  already  ex- 
amined ;  these  the  student  may  divide,  then  separate  the 
extremity  from  the  trunk,  and  place  a  block  under  the 
axilla ;  the  dissection  of  the  arm,  however,  may  be  per- 
formed while  it  remains  connected  to  the  body.  The  mus- 
cles of  the  upper  extremity  are  classed  into  those  of  the 
shoulder  and  arm,  fore  arm  and  hand. 


SECTION  I. 

[The  muscles  which  act  upon  the  superior  extremity,  are  arranged 
with  express  view  to  the  two  great  functions  of  the  extremity,  of 
which  the  one  is  to  prepare  and  carry  food  to  the  mouth,  the  other  to 
defend  the  body,  and  particularly  the  head  and  face  from  external 
violence,  both  of  which  actions  are  prompted  by  the  innate  feeling  of 
self  preservation ;  accordingly  we  find  that  those  muscles  which  ac- 
tually lie  upon  the  extremity  are  so  arranged,  that  all  the  extensor 
muscles  are  situated  upon  the  outer  and  back  part  of  the  limb,  while 
all  the  flexor  muscles,  are  on  the  inner  and  forepart ;  which  enables 
the  extremity  to  be  carried  forward,  inwards,  and  upwards,  in  a  curvi- 
linear direction  so  as  to  cover  the  face  and  thorax  ;  this  arrangement 
is  very  different  from  that  of  the  inferior  extremities,  whose  great 
function  is  progression  and  retrogression  (see  muscles  of  lower  ex- 
tremity.) The  motions  of  the  superior  extremities  are  flexion,  and 
extension,  abduction,  adduction,  rotation,  inwards  and  outwards,  and 
circumduction  ;  these  motions  are  all  performed  by  a  rapid  combina- 
tion of  actions,  on  the  part  of  the  flexor,  and  extensor  muscles,  ex- 
cept in  the  case  of  the  revolution  of  the  radius  upon  the  ulna,  for 
which  purpose  there  are  special  and  appropriate  rotator  muscles.  The 
muscles  which  move  the  upper  extremities,  should  be  classed  as  nearly 
as  may  be  according  to  their  functions,  and  they  may  be  examined 
in  the  five  regions  of  the  trunk,  shoulder,  arm,  fore  arm,  and  hand  ; 
this  arrangement  has  reference  to  the  part  upon  which  the  muscles 
chiefly  lie,  and  it  will  be  seen,  that  those  in  the  region  of  the  trunk, 
are  not  what  are  usually  considered  as  muscles  of  the  extremity  ;  in 
the  several  regions  the  muscles  are  arranged  in  classes  having  refer- 


106  DUBLIN    DISSECTOR. 

ence  to  the  particular  part  of  the  extremity  upon  which  they  act, 
and  lastly,  the  classes  are  divided  into  groups,  according  to  the  par- 
ticular  and  principal  motion  effected  by  their  contraction  as  flexion, 
extension,  &c. 

In  proceeding  with  the  muscles  which  move  the  upper  extremity, 
we  first  examine  those  on  the  region  of  the  trunk,  and  we  here  find 
nine  muscles  on  each  side,  all  of  which  serve  to  connect  the  extrem- 
ity with  the  trunk  ;  these  muscles  are  arranged  in  two  classes,  one 
of  seven  muscles,  which  act  upon  the  shoulder,  a  second  of  two  mus- 
cles, which  act  upon  the  os  brachii. 

FIRST    CLASS,    SEVEN    MUSCLES. 

Trapezius,  Vide  p.  96. 

Levator  Angulii  scapulae,  "     "   99. 

Rhomboideus  Minor,  )  Tr.  7  Qq 
Rhomboideus  Major,  <  v'aeP-  yd> 

Sarratus  Magnus  Anticus,  Vide  p.  69. 

Pectoralis  Minor,  "     "   63. 

Subclavius,  "     "   69. 

Of  these  muscles  the  subclavius  acts  upon  the  clavicle  only,  the 
trapezius  upon  the  clavicle  and  scapula,  and  the  other  five  upon  the 
scapula  only ;  their  combined  action  is  lo  cause  the  scapula  to  rotate 
in  such  manner  as  to  keep  its  glenoid  cavity  in  contact  with  the 
head  of  the  os  brachii,  so  as  to  guard  against  dislocations  of  the 
shoulder  joint.  The  omo-hyoid  muscle  is  attached  to  the  scapula 
but  cannot  effect  its  motions. 

SECOND   CLASS,    TWO    MUSCLES. 

Pectoralis  Major,  Vide  p.  67. 

Latissimus  Dorsi,  "     "  97. 

These  muscles  act  upon  the  os  brachii  to  depress  it,  and  are  an- 
tagonists to  most  of  the  muscles  on  the  region  of  the  shoulder.  The 
muscles  of  these  two  classes  are  situated  on  the  anterior,  lateral  and 
posterior  aspect  of  the  trunk. 

The  muscles  on  the  region  of  the  shoulder  are  six  in  number  on 
each  side,  constituting  a  single  class,  and  arranged  in  two  groups. 

ONE   CLASS,    SIX   MUSCLES. 

First  Group,  five  Muscles. 
Deltoid,  Vide  p.  111. 


Supra  Spinatus, 
Infra  Spinatus, 
Teres  Minor, 
Subscapularis, 


Vide  p.  112. 
Vide  p.  113. 


These  muscles  all  act  upon  the  upper  end  of  the  os  brachii,  except 
the  deltoid  and  for  the  most  part  raise  and  abduct  the  arm,  being  an- 
tagonists  to  the  pectoralis  major,  latissimus  dorsi,  and  teres  major. 

Second  Group  one  Muscle. 

Teres  Major,  Vide  p.  114. 

This  antagonises  the  last  group,  and  is  a  congener  of  the  great 


DUBLIN    DISSECTOR.  107 

pectoral  and  latissimus  dorsi,  with  which  last  it  is  inserted  :  they  de- 
press and  adduct  the  arm.  The  muscles  of  these  two  groups  are 
situated  for  the  most  part  on  the  surfaces  and  borders  of  the  scapula. 
The  muscles  on  the  region  of  the  arm  are  five  in  number  on  each 
side,  arranged  in  two  classes,  the  first,  of  one  muscle  acts  upon  the 
os  brachii,  the  second  of  four  acts  upon  the  fore  arm,  and  is  arranged 
in  two  groups  of  two  muscles  each. 

FIRST    CLASS,    ONE    MUSCLE. 

Coraco-Brachialis,  Vide  p.  114. 

This  muscle  lies  upon  the  inner  aspect  of  the  arm  which  it  raises, 
it  is  therefore  a  congener  of  the  first  group  on  the  region  of  the 
shoulder. 

SECOND    CLASS,    TWO    GROUPS. 

First  Group,  two  Muscles. 

Biceps  Flexor  Cubiti,  Vide  p.  115. 

Brachialis  Anticus,  "     "    116. 

These  muscles  flex  the  fore  arm  upon  the  arm,  the  first  can  also 
act  upon  the  arm. 

Second  Group,  two  Muscles. 

^  Triceps  Extensor  Cubiti,  Vide  p.  117. 

Anconeus,  "     "    129. 

These  muscles  extend  the  fore  arm  upon  the  arm,  and  the  first  can 
also  act  upon  the  arm.  The  muscles  of  the  first  group  are  on  the 
fore  and  inner  part  of  the  arm,  those  of  the  second  upon  the  back 
and  outer  part.  The  muscles  on  the  region  of  the  fore  arm  are  nine- 
teen  in  number  on  each  side,  arranged  in  three  classes,  the  first  of  four 
muscles,  rotates  the  radius  upon  the  ulna.  The  second  of  six  muscles, 
flexes  and  extends  the  hand  upon  the  fore  arm  ;  and  the  third  of  nine 
muscles,  flexes  and  extends  the  fingers  upon  the  hand,  and  can  also 
move  the  hand  upon  the  fore  arm. 

The  first  class  has  two  groups  of  two  muscles  each,  one  for  supina- 
tion,  the  other  for  pronation.  The  second  class  has  two  groups  of  three 
muscles  each,  one  for  flexion  the  other  for  extension  ;  the  third  class 
has  two  groups  one  of  three  muscles,  which  act  upon  the  fingers  gene- 
rally, and  is  divided  into  two  sets,  another  of  six  muscles,  which  act 
upon  individual  fingers,  and  is  divided  into  three  sets  according  to 
the  fingers  to  which  they  are  attached. 

FIRST   CLASS,    TWO   GROUPS. 

First  Group,  two  Muscles 

Supinator  Radii  Longus,  Vide  p,  127. 

Supinator  Radii  Brevis,  "     «    129. 

Second  Group,  two  Muscles. 
Pronator  Radii  Teres,  Vide  p.  122. 

Pronator  Radii  Quadratus,  "     "   126. 

These  four  muscles  are  all  on  the  anterior  aspect  of  the  fore  arm, 


108  DUBLIN    DISSECTOR. 

and  are  all  inserted  into  the  radius,  the  two  first  turn  the  dorsum  of  the 
hand  to  the  ground,  and  the  two  last  the  palm. 

SECOND    CLASS,    TWO    GROUPS. 

First  Group,  three  Muscles. 

Flexor  Carpi  Radialis,  } 

Flexor  Carpi  Ulnaris,  >  Vide  p.  123. 

Flexor  Carpi  Medius,  or  Palmaris  Longus,   i 

Second  Group,  three  Muscles. 
Extensor  Carpi  Radialis  Longus,  )     p..,        ,O7 
Extensor  Carpi  Radialis  Brevis,    (         ae  ?'  J 
Extensor  Carpi  Ulnaris,  "     u    128. 

The  first  group  is  on  the  fore  part,  and  the  second  on  the  posterior 
aspect  of  the  fore  arm. 

THIRD    CLASS,   TWO    GROUPS. 

First  Group,  two  sets. 
First  set,  two  Muscles. 

Flexor  Digitorum  Sublimis  Perforatus,  Vide  p.  124. 

Flexor  Digitorum  Profundus  Perforans,  "     "  125. 

Second  set,  one  Muscle. 
Extensor  Digitorum  Communis,  Vide  p.  128. 

These  three  are  the  common  muscles  of  the  fingers,  the  flexors  are 
on  the  anterior,  and  the  extensor  on  the  posterior  surface  of  the  fore 
arm,  hand,  and  fingers ;  their  primary  action  is  to  flex  or  extend  the 
fingers,  their  secondary  action,  to  flex  or  extend  the  hand. 

Second  Group,  three  Sets. 
First  Set,  four  Muscles. 

Flexor  Longus  Pollicis,  Vide  p.  126. 

Extensor  Ossis  Metacarpi  Pollicis,  i 

Extensor  Primi  Internodii  Pollicis,  £    Vide  p.  130. 

Extensor  Secundi  Internodii  Pollicis,  S 

These,  as  appears  from  their  names,  are  all  long  muscles  of  the 
thumb ;  the  first  is  on  the  anterior,  the  other  three  on  the  posterior 
and  outer  aspect  of  the  fore  arm  ;  these  three  will  also  abduct  the 
hand. 

Second  Set,  one  Muscle. 
Extensor  Indicis,  or  Indicator,  Vide  p.  131. 

Third  Set,  one  Muscle. 

Extensor  Minimi  Digiti.  Vide  p.  129. 

These  two  are  on  the  posterior  face  of  the  fore  arm,  and  can  also 
assist  in  extending  the  hand. 

The  muscles  on  the  region  of  the  hand  are  twenty  in  number  on 
each  side,  arranged  in  two  classes,  in  the  first  class  are  the  twelve 
common  muscles  of  the  hand,  in  two  groups ;  in  the  second  class  are 


DUBLIN    DISSECTOR.  109 

eight  muscles  belonging  to  individual  fingers,  and  arranged  in  three 
groups. 

FIRST    CLASS,    TWO    GROUPS. 

First  Group,  one  Muscle. 

Palmaris  Brevis,  Vide  p.  121. 

This  is  a  superficial  cutaneous  muscle,  it  arches  the  palm. 

Second  Group,  eleven  Muscles. 
Lumbricales,  four,  Vide  p.  132. 

Interossei,  seven,  «     "   133. 

These  are  deep  seated  muscles,  the  lumbricales  and  four  of  the  in. 
terossei  are  to  be  seen  from  the  palm  of  the  hand,  the  other  three  in. 
terossei  from  the  dorsum. 

SECOND    CLASS,    THREE   GROUPS. 

First  Group,  four  Muscles  of  the  Thumb. 
Abductor  Pollicis,         )  ,T., 
Opponens  Pollicis,         \  Vlde  ?'  13L 
Flexor  Pollicis  Brevis,  )    4i       t 
Adductor  Pollicis,         $  *A2t 

Second  Group,  one  Muscle  of  the  Fore  Finger. 
Abductor  Indicis,  Vide  p.  133. 

Third  Group,  three  Muscles  of  the  Little  Finger. 
Abductor  Minimi  Digiti,  > 

Flexor  Brevis  Minimi  Digiti,    >  Vide  p.  133. 
Adductor  Minimi  Digiti,          S 

If  then,  we  review  the  muscles  which  act  directly  upon  the  supe- 
rior extremity,  we  shall  find  that  on  the  region  of  the  trunk  there  are 
nine  muscles,  on  the  region  of  the  shoulder,  six,  on  the  region  of  the 
arm,  five,  on  the  region  of  the  fore  arm,  nineteen,  and  on  the  region 
of  the  hand  twenty,  in  all  fifty-nine  muscles  for  each  extremity,  or 
one  hundred  and  eighteen  for  both  ;  the  same  number  will  be  found 
in  the  classification  of  the  muscles  acting  upon  the  inferior  extremi- 
ties. Of  the  above  number  it  will  be  seen  that  one  hundred  muscles 
are  situated  upon  the  superior  extremities  themselves. 

It  may  be  proper  to  state  here,  that  the  muscles  are  subject  to  cer- 
tain morbid  conditions  of  which  one  is  preternatural  contraction  and 
rigidity  ;  this  is  more  fully  referred  to  in  the  chapter  on  the  muscles  of 
the  lower  extremities.  Inflammation  of  the  muscles  is  less  common 
than  of  some  other  tissues,  it  may  be  either  acute  or  chronic,  it  seldom 
runs  into  suppuration,  mortification,  or  ulceration.  The  muscles  are 
sometimes  in  a  softened,  sometimes  an  indurated,  and  occasionally 
even  an  ossified  state  ;  this  last  affection  is  very  rare,  but  a  remark- 
able case  is  recorded  in  which  most  of  the  muscles  of  the  extremities 
were  converted  into  a  solid  mass  of  bone ;  the  muscles  of  the  shoulder, 
loins,  and  calf,  are  most  subject  to  this  change.  The  muscles  some- 
times undergo  a  fibrous  or  a  fatty  transformation,  they  may  also  be 
hypertrophied  or  atrophied  ;  tubercular,  melanotic,  schirrous,  and  en- 
10 


110  DUBLIN    DISSECTOR, 

cephaloid,  deposit  are  very  rare.  These  organs  are  sometimes  infested 
by  parasitic  animals ;  many  of  the  muscles  are  subject  to  congenital 
vareties,  and  those  for  the  most  part  have  their  type  in  the  muscles 
of  different  inferior  animals.] 

DISSECTION   OF   THE   MUSCLES    OF   THE    SHOULDER   AND   ARM. 

DISSECT  off  the  integuments  from  the  shoulder  and  arm 
as  low  as  the  bend  of  the  elbow ;  beneath  the  skin  and 
adipose  substance  is  the  brachial  aponeurosis ;  this  is  weak 
and  imperfect  in  some  situations  as  on  the  deltoid  muscle ; 
in  others  it  is  strong  and  well  marked,  and  it  increases  in 
strength  as  it  descends ;  it  is  connected  posteriorly  to  the 
spine  of  the  scapula,  and  to  the  infra-spinatus  muscle  ;  in- 
ferior to  this  it  receives  an  addition  of  fibres  from  the  in- 
sertion of  the  deltoid ;  internally  it  is  in  part  continued 
along  the  vessels  from  the  fascia  "of  the  axilla,  and  in  part 
also  from  the  tendons  of  the  great  pectoral  and  latissimus 
dorsi ;  it  invests  the  whole  arm,  confining  the  muscles  in 
their  situation,  and  pressing  them  towards  each  other,  par- 
ticularly along  the  inner  side  of  the  arm,  so  as  to  overlap 
the  brachial  vessels  and  nerves :  as  it  descends  it  adheres 
to  the  lateral  ridges  of  the  humerus,  which  lead  to  the 
condyles ;  these  connexions  are  named  inter-muscular  liga- 
ments;  the  internal  is  augmented  by  a  prolongation  of 
the  coraco-brachialis  tendon,  and  the  external  by  fibres  from 
the  deltoid :  the  fascia  of  the  fore  arm  we  shall  examine 
afterwards.  Between  the  integuments  and  fascia  of  the 
arm  we  notice  two  cutaneous  veins,  the  cephalic  on  the 
outer,  and  the  basilic  on  the  inner  side ;  the  cephalic  will 
be  found  hereafter  to  commence  about  the  thumb,  and  to 
ascend  along  the  radial  side  of  the  fore  arm,  and  having 
passed  the  elbow  joint,  it  is  now  seen  continuing  its  course 
up  the  arm,  at  first  on  the  outer  side  of  the  biceps,  and 
afterwards  between  the  deltoid  and  great  pectoral  muscles 
to  the  clavicle,  beneath  which  it  sinks  to  join  the  axillary 
vein;  the  cephalic  vein  is  unaccompanied  by  nerves  in  its 
course  up  the  arm,  but  in  the  dissection  of  the  fore  arm 
the  external  cutaneous  nerve  will  be  seen  closely  connected 
with  it.  The  basilic  vein  will  be  found  to  commence  about 
the  little  finger,  to  ascend  along  the  ulnar  side  of  the  fore 
arm,  and  to  pass  over  the  elbow  joint ;  it  is  now  seen  con- 
tinuing its  course  on  the  inner  side  of  the  biceps,  between 
the  skin  and  fascia,  and  about  the  middle  of  the  arm  it 
perforates  the  latter,  to  join  one  of  the  deep  brachial  veins  ; 
in  some  it  continues  superficial  as  high  as  the  axilla,  where 
it  joins  the  axillary  vein ;  the  basilic  vein  in  the  arm  is 
accompanied  by  the  cutaneous  nerves  of  Wrisberg,  which 
having  escaped  from  the  intercostal  branches  of  the  second 


DUBLIN     DISSECTOR.  Ill 

and  third  dorsal  nerves,  and  passed  across  the  axilla,  are 
then  distributed  to  the  integuments  on  the  inner  side  of 
the  arm ;  inferiorly  the  internal  cutaneous  branch  of  the 
brachial  plexus  accompanies  this  vein,  and  continues  with 
it  along  the  fore  arm ;  dissect  off  the  fascia  and  cellular 
membrane  from  the  muscles  of  the  shoulder  and  arm. 
The  muscles  of  the  shoulder  are  six  in  number,  viz.  the 
deltoid,  supra  and  infra-spinatus,  teres  minor  and  major, 
and  sub-scapularis ;  those  of  the  arm  are  four  in  number, 
viz.  the  biceps,  coraco-brachialis,  brachialis  anticus  and 
triceps ; — first  examine  the  muscles  of  the  shoulder. 

DELTOIDES,  very  thick  and  strong,  triangular,  arises  ten- 
dinous from  the  lower  edge  of  the  spine  of  the  scapula, 
and  rather  fleshy  from  the  anterior  edge  of  the  acromion, 
and  of  the  external  third  of  the  clavicle ;  the  fibres  con- 
verge and  descend  obliquely,  the  posterior  forwards,  the 
anterior  backwards,  and  the  middle  at  first  outwards,  and 
then  vertically  downwards ;  inserted  tendinous  into  a  rough 
surface,  about  two  inches  in  extent,  situated  on  the  outer 
side  of  the  humerus,  and  commencing  just  above  its  centre. 
Use,  to  abduct  and  raise  the  arm,  the  anterior  fibres  can 
also  draw  it  forwards,  the  posterior  backwards,  and  when 
the  arm  is  by  the  side,  these  portions  can  rotate  it  in- 
wards or  outwards.  This  muscle  can  also  move  the 
scapula  on  the  arm  when  the  latter  is  fixed,  as  in  the 
case  of  a  fall  upon  the  hand  or  elbow,  or  in  lifting  a 
very  heavy  weight;  under  these  circumstances  this  mus- 
cle sometimes  co-operates  with  the  great  pectoral  and 
latissimus  dorsi,  to  dislocate  the  head  of  the  humerus  into 
the  axilla.  The  deltoid  is  covered  only  by  the  skin,  and 
a  few  fibres  of  the  platysma;  its  origin  corresponds  to  the 
insertion  of  the  trapezius,  with  which  it  is  often  connected 
by  aponeurotic  fibres  ;  its  insertion  is  surrounded  by  the 
origin  of  the  brachialis  anticus,  and  lies  between  the 
biceps  'and  second  head  of  the  triceps ;  its  posterior  mar- 
gin is  thin,  and  sends  off  an  aponeurosis  to  cover  the  in- 
fra-spinatus muscle;  its  anterior  edge  is  separated  from 
the  great  pectoral,  by  the  cephalic  vein,  some  cellular 
membrane,  and  a  small  artery.  This  muscle  is  fleshy  on 
its  external  surface,  coarse  and  rough,  and  composed  of 
several  distinct  triangular  fasciculi.  Divide  it  transverse- 
ly, and  reflect  each  portion,  and  we  shall  then  see  that  its 
structure  is  very  complex,  and  that  its  internal  surface  is 
much  more  tendinous;  a  large  bursa  is  also  seen  beneath 
it ;  this  bursa  extends  under  the  acromion,  and  is  expanded 
on  the  tendon  of  the  supra-spinatus,  and  on  the  capsular 
ligament ;  it  allows  the  deltoid  muscle  and  the  exterior  of 
the  shoulder  joint  to  glide  easily  against  each  other  ;  the 


112  DUBLIN    DISSECTOR. 

deltoid  also  covers  the  coracoid  process,  the  muscles  which 
are  attached  to  it,  all  the  small  muscles  connected  to  the 
capsular  ligament,  the  insertion  of  the  great  pectoral,  and 
the  circumflex  vessels  and  nerves. 

[Variety.  A  slip  sometimes  arises  from  the  anterior  edge  of  the 
scapula  and  joins  the  deltoid.] 

SUPRA-SPINATUS,  fills  the  fossa  of  that  name,  and  arises 
from  all  that  portion  of  the  scapula  above  its  spine,  which 
is  engaged  in  forming  this  fossa,  also  from  a  strong  fascia 
which  covers  the  muscle ;  the  fibres  pass  forwards  beneath 
the  acromion  process  and  triangular  ligament,  end  in  a 
tendon  which  glides  over  the  neck  of  the  scapula,  (a  bursa 
intervenes;)  inserted  into  the  upper  and  forepart  of  the 
great  tuberosity  of  the  humerus,  into  the  most  anterior  of 
the  three  depressions  which  are  marked  on  that  surface. 
Use,  to  assist  the  deltoid  in  raising  and  abducting  the  arm, 
it  also  strengthens  the  capsular  ligament,  and  draws  it  out 
of  the  angle,  which  is  formed  by  the  elevation  of  the  arm, 
between  the  humerus  and  the  glenoid  cavity  ;  it  also  pres- 
ses the  head  of  the  humerus  and  glenoid  cavity  towards 
each  other,  prevents  the  head  of  the  former  from  descend- 
ing out  of  the  latter,  and  thus  it  becomes  the  antagonist  to 
the  pectoral,  deltoid,  and  those  other  long  muscles,  which 
have  a  tendency  to  dislocate  the  head  of  the  bone  into  the 
axilla.  This  muscle  is  covered  by  the  trapezius,  much 
cellular  membrane  and  fat  and  by  a  strong  aponeurosis  ; 
its  insertion  is  concealed  by  the  deltoid,  and  the  large 
bursa  beneath  that  muscle,  also  by  the  acromion  process 
and  triangular  ligament ;  the  tendon  is  inseparably  con- 
nected to  the  eapsular  ligament. 

INFRA-SPINATUS,  is  inferior  to  the  last,  flat  and  triangular ; 
arises  fleshy  from  the  inferior  surface  of  the  spine  of  the 
scapula,  and  from  the  dorsum  of  this  bone,  below  this  pro- 
cess, as  low  down  as  the  posterior  ridge  on  the  inferior 
costa,  but  not  from  the  rough  surface  on  the  inferior  angle 
of  the  scapula ;  it  also  arises  from  the  aponeurosis  which 
covers  it ;  the  inferior  fibres  ascend  obliquely  forwards, 
the  superior  run  horizontally;  all  converge,  and  are  in- 
serted by  a  strong  tendon,  which  covers  and  adheres  to  the 
outer  part  of  the  capsular  ligament,  into  the  middle  of  the 
external  or  greater  tuberosity  of  the  humerus,  below  the 
supra-spinatus.  Use,  to  assist  the  superior  part  of  the  del- 
toid in  raising  the  arm,  and  drawing  it  backwards,  also  in 
rotating  it  outwards :  when  the  arm  has  been  raised,  its 
lower  fibres  can  depress  it ;  it  will  also  draw  the  capsular 
ligament  out  of  the  joint,  and  strengthen  the  articulation  ; 
it  is  covered  by  the  trapezius  and  deltoid ;  but  between 
these  and  the  latissimus  dorsi,  a  portion  of  it  is  superficial. 


DUBLIN    DISSECTOR.  113 

It  lies  on  the  bone,  and  the  scapular  vessels  and  nerves ;  a 
large  bursa  lies  between  its  tendon  and  the  neck  of  the 
scapula. 

TERES  MINOR,  small  and  narrow,  inseparably  attached  to 
the  last  muscle,  along  the  lower  edge  of  which  it  runs  ;  it 
arises  from  a  depression  between  the  two  ridges  on  the  in- 
ferior costa  of  the  scapula,  extending  from  the  neck  of  the 
bone  to  within  an  inch  and  a  half  of  its  inferior  angle,  from 
the  fascia  which  covers  it,  and  from  ligamentous  septa, 
which  enclose  it;  the  fibres  ascend  obliquely  forwards 
and  outwards,  cover  and  adhere  to  the  capsule,  and  are  in- 
serted below  the  infra-spinatus  into  the  inferior  depression 
on  the  great  tuberosity  of  the  humerus.  Use,  to  co-operate 
with  the  last  muscle.  The  origin  of  the  teres  minor  is  be- 
tween and  overlapped  by  the  infra-spinatus  and  teres  ma- 
jor muscles ;  its  middle  portion  is  superficial,  and  its  in- 
sertion is  covered  by  the  deltoid ;  it  lies  on  the  scapula, 
sub-scapular  vessels,  capsular  ligament,  and  long  head  of 
the  triceps,  which  last  separates  it  from  the  teres  major. 

SUB-SCAPULARIS,  is  situated  on  the  inner  side  of  the  sca- 
pula, opposite  to  the  three  last  described  muscles,  broad 
and  triangular,  the  base  behind,  the  apex  before  :  it  arises 
from  all  the  surface  and  circumference  of  the  sub-scapu- 
lar fossa,  the  fibres  run  in  thick  fasciculi  up  wards  and  for- 
wards, and  all  converge  towards  the  neck  of  the  scapula, 
over  which  they  glide,  beneath  the  coracoid  process,  and 
the  muscles  which  are  inserted  into  it ;  they  .end  in  a  ten- 
don which  is  intimately  united  to  the  capsular  ligament, 
and  inserted  into  the  internal  or  small  tubercle  of  the  hu- 
merus; this  muscle  is  covered  by  the  scapula  and  the 
muscles  of  the  shoulder;  its  inferior  edge  is  in  contact 
with  the  teres  major;  its  internal  surface,  which  forms 
part  of  the  axilla,  is  connected  to  the  serratus  magnus,  and 
to  the  axillary  vessels  and  nerves,  by  loose  cellular  mem- 
brane :  a  large  bursa,  very  often  communicating  with  the 
joint,  lies  between  its  tendon  and  the  neck  of  the  scapula, 
beneath  the  coracoid  process:  another  smaller  bursa  is 
sometimes  situated  lower  down,  between  the  tendon  and 
the  -capsular  ligament  Use,  this,  which  is  the  strongest  of 
these  capsular  muscles,  strengthens  the  inner  side  of  the  ar- 
ticulation, and  guards  against  dislocation  when  the  el- 
bow is  suddenly  drawn  backwards  and  outwards.  This 
muscle  can  depress  and  adduct  the  arm,  draw  it  back- 
wards, and  rotate  it  inwards,  so  as  to  turn  the  palm  of  the 
hand  backwards,  thus  it  antagonizes  the  infra-spinatus  and 
teres-minor  muscles. 

The  deltoid  and  the  four  capsular  musdfes,  which  have 
been  just  described,  are  of  great  use  to  the  shoulder  arti- 
10* 


114  DUBLIN    DISSECTOR. 

culation ;  the  head  of  the  humerus  is  so  large,  the  glenoid 
cavity  so  superficial,  and  the  capsular  ligament  so  loose 
and  long,  that,  but  for  these  muscles,  the  bones  could  not 
remain  in  apposition ;  hence,  in  cases  of  paralysis  of  the 
muscles  of  this  region,  the  joint  becomes  elongated  and 
flattened,  and  a  partial  dislocation  exists  ;  in  the  dissect- 
ing-room also,  if  we  divide  all  the  muscles  surrounding 
the  capsule,  and  leave  the  latter  uninjured,  the  bones  will 
no  longer  be  in  contact ;  these  muscles,  therefore,  serve  to 
strengthen  the  capsule,  to  keep  the  head  of  the  humerus 
pressed  against  the  glenoid  cavity,  and  thus  to  counteract 
that  tendency  to  dislocate  the  head  of  the  bone,  which  the 
larger  muscles  of  the  limb  frequently  have,  in  consequence 
of  their  insertion  being  at  such  a  distance  from  the  centre 
of  the  joint,  added  to  the  anatomical  imperfections  in  the 
latter  already  alluded  to ;  which  imperfections,  however, 
are  much  counterbalanced  by  the  great  mobility  which 
the  joint  enjoys  in  consequence  of  this  formation,  by  the 
numerous  opposing  muscles  which  serve  to  protect  the  ar- 
ticulation, and  by  the  rotatory  motion  of  which  the  scapula 
is  allowed  to  partake. 

TERES  MAJOR,  long  and  flat,  arises  from  a  rough  flat  sur- 
face on  the  inferior  angle  of  the  scapula,  below  the  infra- 
spinatus  ;  it  forms  a  thick  fleshy  belly,  which  ascends  for- 
wards and  outwards  to  the  inner  side  of  the  arm,  and  ends 
in  a  broad  thin  tendon,  which  is  at  first  closely  connected 
to  the  back  of  the  tendon  of  the  latissimus  dorsi  ;  but  near 
the  humerus,  a  small  bursa  intervenes,  and  is  inserted  into 
the  inner  or  posterior  edge  of  the  bicipital  groove,  behind 
the  tendon  of  the  latissimus,  and  in  general,  but  not  al- 
ways, extending  lower  down  than  it.  Use,  to  rotate  the  hu- 
merus inwards,  to  adduct  and  draw  it  downwards  and 
backwards  ;  also  to  draw  forward  the  inferior  angle  of  the 
scapula;  whereby  it  not  only  assists  the  capsular  muscles 
in  retaining  these  two  bones  in  apposition,  but  it  also 
keeps  the  glenoid  cavity  opposed  to  the  head  of  the  hume- 
rus. The  origin  of  this  muscle  is  superficial,  the  latissi- 
mus dorsi  sometimes  overlaps  it;  it  is  here  connected  to 
the  infra  spinatus  and  teres  minor ;  from  the  latter  the 
long  head  of  the  triceps  afterwards  separates  it ;  it  passes 
anterior  to  this  muscle,  and  assists  the  latissimus  dorsi  in 
forming  the  posterior  fold  of  the  axilla. 

The  four  muscles  of  the  arm  are  the  coraco-brachialis, 
biceps,  and  brachialis  anticus  in  front,  and  the  triceps  be- 
hind. 

CORACO-BRACHIALIS  arises  tendinous  and  fleshy  from  the 
point  of  the  coracoid  process,  and  from  the  tendon  of  the 
short  head  of  the  biceps ;  it  descends  obliquely  forwards, 


DUBLIN    DISSECTOR.  115 

and  is  inserted,  chiefly  tendinous,  into  the  internal  side  of 
the  humerus,  about  the  middle,  and  into  the  ridge  leading 
to  the  internal  condyle,  by  an  aponeurosis,  which  forms 
the  internal  inter-muscular  ligament,  which  is  joined  to 
the  fascia  of  the  arm.  Use,  to  adduct,  raise,  and  draw  for- 
wards the  arm  ;  also  to  rotate  it  outwards.  The  origin  of 
this  muscle  cannot  be  separated  from  the  short  head  of  the 
biceps,  but  as  it  descends,  it  lies  behind,  and  to  the  inner 
side  of  that  muscle  ;  it  is  covered  above  by  the  deltoid  and 
pectoral ;  a  small  portion  of  it  below  is  superficial,  and  is 
seen  between  the  biceps  and  triceps ;  its  insertion  is  just 
below  that  of  the  teres  major,  and  separates  the  brachialis 
anticus  and  posticus :  the  coraco-brachialis  passes  over 
the  tendon  of  the  subscapular,  latissimus,  and  teres  mus- 
cles ;  the  brachial  artery  and  median  nerve,  at  first  lie  to 
its  inner  side,  but  pass  superficial  to  its  insertion  ;  the  belly 
of  this  muscle  is  generally,  but  not  always,  perforated 
by  the  external  or  musculo-cutaneous,  or  perforans  Casse- 
rii  nerve. 

BICEPS,  is  situated  along  the  fore  part  of  the  humerus, 
and  consists  of  two  portions  superiorly,  the  external  or 
long,  the  internal  or  short ;  the  internal  arises  tendinous 
from  the  coracoid  process,  between  the  coraco-brachialis 
and  triangular  ligament ;  it  soon  becomes  fleshy,  descends 
obliquely  outwards,  and  a  little  above  the  middle  of  the 
humerus  is  united  to  the  external  or  long  head,  which  arises 
by  a  long  tendon,  from  the  upper  part  of  the  glenoid  liga- 
ment of  the  scapula  ;  this  tendon  passes  outwards  through 
the  joint  over  the  head  of  the  humerus,  within  the  capsu- 
lar  ligament,  but  external  to  the  synovial  membrane ;  it 
then  descends  into  the  groove,  between  the  two  tuberosities 
of  this  bone,  in  which  groove  it  is  bound  down  by  tendin- 
ous fibres,  continued  from  the  capsular  ligament,  and  from 
the  adjacent  tendons ;  the  synovial  membrane  of  the  joint 
is  reflected  on  this  tendon  at  its  origin,  and  is  again  reflect- 
ed from  it  inferiorly  on  the  parietes  of  the  groove,  between 
the  tendons  of  the  great  pectoral,  latissimus  dorsi,  and  teres 
major  muscles ;  thus,  although  the  tendon  passes  through 
the  cavity  of  the  joint,  it  is,  strictly  speaking,  external  to 
the  synovial  membrane.  A  little  below  the  middle  of  the 
humerus,  these  two  portions  of  the  biceps  unite  in  a  large 
fleshy  belly,  which,  descending  to  within  about  an  inch 
and  a  half  of  the  elbow  joint,  ends  in  a  flat  tendon ;  this 
sends  off  a  process  called  the  semi  lunar  fascia,  to  join  the 
general  aponeurosis  of  the  fore  arm,  and  then  sinks  below 
the  joint  into  a  triangular  hollow  between  the  supinator 
longus  and  pronator  teres,  and  is  inserted  into  the  back  part 
of  the  tubercle  of  the  radius  :  a  bursa  intervenes  between 


116  DUBLIN    DISSECTOR. 

this  tendon  and  the  anterior  part  of  the  tubercle,  which  is 
covered  by  cartilage  ;  the  semilunar  fascia  which  arises  nar- 
row from  the  forepart  of  this  tendon,  opposite  the  bend  of 
the  elbow,  passes  upwards  and  inwards,  expanding  towards 
the  internal  condyle,  to  which,  and  to  the  muscles  proceed- 
ing from  it,  some  of  its  fibres  are  attached :  the  remaining 
become  continuous  with  the  aponeurosis  of  the  fore  arm. 
Use,  to  flex  the  fore  arm,  and  make  tense  its  fascia ;  also  to 
abduct  and  raise  the  arm.  When  the  hand  is  prone,  the 
first  effect  of  the  contraction  of  the  biceps  is  to  roll  -the 
radius  outwards,  and  turn  the  hand  supine ;  the  long  ten- 
don of  the  biceps,  by  passing  over  the  head  of  the  humer- 
us,  prevents  this  bone  being  dislocated  upwards  and  out- 
wards, as  otherwise  might  occur,  in  consequence  of  a  fall, 
or  of  a  sudden  muscular  contraction  :  the  biceps  may  also 
assist  the  coraco-brachialis,  in  rotating  the  scapula  on  the 
humerus,  so  as  to  depress  the  point  of  the  shoulder.  The 
long  head  of  the  biceps  is  concealed  by  the  deltoid,  supra- 
spinatus  and  capsular  ligament;  the  short  head  by  the 
great  pectoral  and  deltoid :  not  unfrequently  this  muscle 
has  another  origin  from  the  humerus  below  its  head ;  in 
some  a  fasciculus  unites  it  to  the  coraco-brachialis,  and  in 
others  to  the  brachialis  anticus  muscle,  which  lies  be- 
hind it 

[This  muscle  is  very  liable  to  varieties;  sometimes  its  two  parts 
remain  separate  as  far  as  the  elbow,  in  a  few  rare  cases  it  has  had 
five  heads.] 

The  belly  of  the  biceps  is  superficial,  and  lies  on  the 
brachialis  anticus,  so  also  is  the  tendon  in  its  passage  over 
the  elbow  joint ;  the  brachial  artery  descends  along  its  in- 
ternal border,  and  somewhat  overlapped  by  it,  in  the  mid- 
dle and  lower  part  of  the  arm.  This  muscle  or  its  tendon 
will  serve  as  a  guide  in  the  living  subject,  in  case  we  are 
required  to  tie  this  vessel,  but  superiorly  the  coraco-brach- 
ialis intervenes ;  the  semilunar  fascia  is  extended  over  the 
brachial  artery  and  nerve,  and  affords  them  some,  but  not 
a  constant  protection,  in  performing  venesection  in  the 
median  basilic  vein,  which  vein  is  superficial  to  this  fas- 
cia, but  parallel,  and  often  so  close  to  the  artery  as  to  ex- 
pose the  latter  to  some  danger  in  that  operation-  In  dislo- 
cation, and  in  other  injuries  of  the  shoulder  joint,  the  long 
tendon  of  the  biceps  is  sometimes  ruptured. 

BRACHIALIS  ANTICUS,  or  EXTERNUS,  improperly  called  by 
some  INTERNUS,  arises  from  the  centre  of  the  humerus  by 
two  fleshy  slips,  one  on  either  side  of  the  insertion  of  the 
deltoid,  from  the  forepart  of  the  bone  down  to  the  condy- 
les,  and  on  each  side  as  far  as  the  inter-muscular  liga- 


DUBLIN    DISSECTOR.  117 

ments ;  the  fibres  descend  converging,  pass  anterior  to  the 
elbow  joint,  adhere  to  the  synovial  membrane,  and  are  in- 
serted by  a  strong  tendon  into  the  coronoid  process  of  the 
ulna,  and  into  a  rough  surface  on  this  bone  beneath  that 
process.  Use,  to  flex  the  fore  arm,  and  in  doing  so  it  draws 
the  synovial  membrane  out  of  the  angle  of  the  joint ;  it  also 
strengthens  this  articulation  in  its  extended  state,  by  press- 
ing the  ulna  against  the  humerus,  and  supporting  the  joint 
in  front ;  this  muscle  is  covered  by  the  biceps  and  by  the 
brachial  vessels  and  nerves ;  external  to  the  biceps  it  is 
superficial;  its  external  head  is  the  longer,  and  lies  be- 
tween the  deltoid  and  second  head  of  the  triceps  ;  the  in- 
ternal separates  the  deltoid  from  the  coraco-brachialis; 
the  tendon  passes  deep  into  the  hollow  at  the  elbow,  behind 
the  tendon  of  the  biceps,  and  is  inserted  on  its  internal  side  ; 
a  fleshy  fasciculus  often  unites  this  muscle  and  the  biceps 
about  the  middle  of  the  arm. 

[A  fasciculus  sometimes  passes  off  to  the  supinator  radii  longus, 
and  sometimes  there  is  a  second  muscle  but  small, at  the  outer  edge 
of  the  main  muscle,  having  nearly  the  same  attachments.] 

TRICEPS  EXTENSOR  CUBITI,  covers  the  back  of  the  humer- 
us, and  extends  from  the  scapula  to  the  olecranon  ;  it  con- 
sists superiorly  of  three  portions,  viz.  the  middle  or  long, 
the  second  or  external,  and  the  third  or  internal,  or  short 
head,  or  the  brachialis  interims  or  posticus. 

The  long,  or  middle  head,  arises  by  a  flat  short  tendon 
about  an  inch  broad,  from  the  lower  part  of  the  neck  of 
the  scapula,  and  from  the  anterior  portion  of  the  inferior 
costa ;  it  also  adheres  to  the  inferior  part  of  the  capsular 
ligament ;  it  soon  ends  in  a  large  fleshy  belly  which  de- 
scends along  the  back  part  of  the  humerus,  that  surface 
which  is  towards  the  bone  continues  tendinous  for  some 
distance :  about  the  superior  third  of  the  arm  it  joins  the 
second  or  external  head,  which  arises  immediately  below  the 
insertion  of  the  teres  minor  by  a  narrow  tendinous  and 
fleshy  slip,  from  a  ridge  on  the  outer  side  of  the  humerus 
commencing  below  the  great  tuberosity,  and  leading  down 
to  the  external  condyle ;  it  also  arises  from  the  bone  be- 
hind this  ridge,  from  the  interrnuscular  ligament,  and  from 
the  external  condyle,  by  a  tendon  which  passes  upwards 
and  inwards,  and  joins  the  remainder  of  the  muscle ;  these 
inferior  fibres  are  parallel  to  the  anconseus ;  the  third,  or 
short  head,  or  brachialis  internus,  or  posticus,  improperly  call- 
ed brachialis  externus,  arises  narrow  on  the  inside  of  the 
humerus,  above  its  centre,  commencing  tendinous  just  be- 
low the  insertion  of  the  teres  major,  and  continuing  to 
arise  from  the  ridge  which  leads  to  the  internal  condyle, 


118  DUBLIN    DISSECTOR. 

and  from  the  internal  intermuscular  ligament;  these 
three  portions  of  the  triceps  unite  above  the  middle  of 
the  arm,  and  descending  along  its  posterior  part,  end  in  a 
flat  broad  tendon  which  consists  of  two  laminae,  a  super- 
ficial and  a  deep ;  the  former  is  continued  over  the  flat 
triangular  surface  of  the  olecranon  into  the  fascia  on  the 
back  part  of  the  fore  arm,  the  latter,  which  is  stronger 
but  narrower,  is  inserted  into  the  olecranon  process.  Use, 
to  extend  the  fore  arm  on  the  arm,  and  by  its  long  portion 
to  carry  the  arm  backwards,  and  in  some  cases  to  adduct 
it;  it  also  draws  up  the  synovial  membrane  from  be- 
tween the  olecranon  process  and  the  humerus,  and  thus 
protects  it  from  pressure  in  the  extended  state  of  the  limb. 
The  long  head  gives  support  to  the  inferior  part  of  the 
capsular  ligament  of  the  shoulder,  and  so  tends  to  pro- 
tect that  joint  against  dislocation,  in  that  situation  where 
it  would  be  most  likely  to  occur.  The  sudden  contraction 
of  the  triceps  during  life  sometimes  breaks  off  the  ole- 
cranon process,  and  draws  upwards  the  separated  portion, 
of  course  the  individual  loses  for  some  time  the  power  of 
extending  the  fore  arm ;  the  fractured  piece,  however,  is 
prevented  being  separated  to  any  considerable  distance  by 
the  aponeurosis  of  the  triceps  which  covers  the  olecranon, 
and  which  joins  the  fascia  of  the  fore  arm,  and  also  by  the 
inferior  fibres  of  this  muscle,  which  being  connected  to  the* 
condyles,  and  having  to  ascend  a  little  to  the  olecranon, 
tend  to  draw  down  its  fractured  portion.  The  first,  or  long 
head  of  the  triceps,  arises  and  descends  between  the  two 
teres  muscles  ;  the  second,  or  outer  head  commences  below 
the  teres  minor ;  and  the  third,  or  the  brachialis  internus 
or  posticus,  below  the  teres  major ;  the  long  and  the  second 
head  are  covered  above  by  the  deltoid,  the  remainder  of 
them  is  superficial ;  the  second  lies  external  to  the  supina- 
tor  longus  and  radial  extensors  of  the  carpus ;  the  third  or 
internal  head  is  also  superficial,  and  lies  between  the  bra- 
chialis anticus  and  coraco-brachialis  anteriorly,  and  the 
long  portion  of  the  triceps  posteriorly  ;  the  ulnar  nerve  de- 
scends along  this,  and  the  radial  or  spiral  separates  it  from 
the  second  or  outer  head ;  a  small  bursa  lies  between  the 
tendon,  and  the  point  of  the  olecranon,  a  larger  one  between 
the  skin  and  the  aponeurosis  which  covers  that  process ;  this 
superficial  bursa  is  peculiarly  liable  to  inflammation,  which 
is  generally  of  an  unhealthy  character,  in  consequence  of 
an  injury,  such  as  a  fall  upon  the  elbow  producing  a  super- 
ficial lacerated  wound.  In  the  dissection  of  the  muscles  of 
the  arm,  we  should  notice  the  course  of  the  brachial  artery 
and  of  its  principal  branches,  also  the  divisions  of  the  axil- 
lary plexus  of  nerves :  the  cutaneous  veins  have  been  al- 


DUBLIN    DISSECTOR.  119 

ready  noticed ;  the  deep  veins  accompany  the  arteries,  tw*> 
to  each. 

The  brachial  artery,  which  is  the  continuation  of  the  sub- 
clavian  and  axillary,  descends  obliquely  outwards,  along 
the  inner  side,  first  of  the  coraco-brachialis,  and  afterwards 
of  the  biceps  ;  near  the  elbow  it  inclines  forwards*  and  then 
sinks  beneath  the  fascia  of  the  biceps,  and  a  little  below 
the  bend  of  the  elbow  it  divides  into  the  radial  and  ulnar 
arteries.  In  this  course  it  is  covered  by  the  fascia  and  in- 
teguments, and  overlapped  a  little  by  the  biceps ;  it  is  sur- 
rounded by  a  sheath  of  cellular  membrane,  which  also 
contains  the  two  vense  comites;  the  internal  cutaneous 
nerve  lies  superficial  to  it ;  the  median  or  brachial  is  also 
superficial  to  it  above,  and  rather  to  its  outer  side ;  about 
the  middle  of  the  arm,  it  crosses  the  artery,  and  inferiorly 
it  is  almost  always  to  its  ulnar  or  inner  side.  The  ulnar 
nerve  lies  internal  to  the  artery,  and  at  some  distance  from 
it  inferiorly ;  the  radial  or  spiral  nerve  is  posterior  to  it, 
and  separates  it  above  from  the  triceps.  In  this  course  the 
artery  passes  over  the  tendons  of  the  latissimus  and  teres, 
a  small  part  of  the  triceps,  the  coraco-brachialis,  and  the 
brachialis  anticus.  The  brachial  artery  gives  off  several 
muscular  branches  from  its  external  side  ;  and  from  its  in- 
ternal the  superior  profunda,  which  accompanies  the  spiral 
nerve  round  the  back  of  the  humerus  to  its  external  side  ; 
the  inferior  profunda  which  descends  along  with  the  ulnar 
nerve  towards  the  inner  condyle,  and  the  anastomotica 
magna,  which  runs  towards  the  inner  side  of  the  elbow 
joint. — See  Anatomy  of  the  Vascular  System. 

The  branches  of  the  brachial  plexus  of  nerves,  which 
are  met  with  in  the  dissection  of  the  arm,  are  six  in  num- 
ber :  first,  the  internal  cutaneous,  which  has  been  already 
noticed  ;  second,  the  external  cutaneous,  or  musculo  cutane- 
ous, or  perforans  Casserii,  pierces  the  coraco-brachialis 
muscle,  descends  obliquely  outwards  between  the  biceps 
and  brachialis  anticus,  to  which  it  sends  several  filaments, 
and  at  the  anterior  edge  of  the  supinator  longus  it  becomes 
cutaneous,  descending  along  with  the  cephalic  vein  and  its 
branches  ;  third,  the  median  or  brachial  nerve  accompanies 
the  brachial  artery  to  the  bend  of  the  elbow,  and  sinks  be- 
neath the  muscles  of  the  fore  arm,  in  the  dissection  of 
which  the  remainder  of  its  course  will  be  exposed  :  fourth, 
the  ulnar  nerve  descends  along  the  inner  portion  of  the 
triceps,  or  the  brachialis  intern  us,  runs  behind  the  inner 
condyle,  and  is  then  distributed  to  the  muscles  of  the  fore 
arm  and  hand  ;  fifth,  the  musculo-spiral,  or  radial  nerve,  de- 
scends between  the  second  and  third  head  of  the  triceps, 
and  winds  round  the  back  part  of  the  humerus,  supplying 


120  DUBLIN    DISSECTOR. 

the  triceps  in  its  course ;  it  next  runs  spirally  forwards  to 
the  forepart  of  the  bone,  between  the  supinator  longus  and 
brachialis  anticus;  it  then  descends  over  the  forepart  of 
the  elbow  joint  to  the  muscles  of  the  fore  arm,  where  we 
shall  trace  it  afterwards ;  sixth,  the  circumflex,  or  articular 
nerve,  accompanied  by  the  posterior  circumflex  artery, 
passes  out  of  the  axilla  between  the  long  head  of  the  triceps 
and  the  neck  of  the  humerus,  winds  round  the  latter  be- 
neath the  deltoid  muscle,  to  which  its  branches  are  distri- 
buted.— See  Anatomy  of  Nervous  System. 


SECTION  II. 

DISSECTION    OF    THE    FORE    ARM    AND    HAND. 

REMOVE  the  integuments  from  the  front  and  back  of  the 
fore  arm  and  hand,  and  the  investing  fascia  will  be  exposed, 
together  with  the  sub-cutaneous  nerves  and  veins :  the  lat- 
ter may  be  noticed  first.  The  basilic  vein  is  seen  to  arise 
by  small  branches  from  the  sides  of  the  little  finger,  one  of 
which  is  named  sahatella ;  it  then  ascends  along  the  ulnar 
side  of  the  fore  arm,  receiving  in  this  course  small  branches 
from  the  front  and  back  of  the  arm,  and  passing  anterior 
to  the  internal  condyle,  it  is  joined  by  the  median  basilic ; 
it  then  ascends  along  the  inner  side  of  the  arm,  passes  be- 
neath the  fascia,  and  joins  one  of  the  deep  brachial  veins  ; 
sometimes  it  continues  in  a  superficial  course  to  the  axilla, 
and  joins  the  axillary  vein.  The  cephalic  vein  commences 
by  several  small  branches  about  the  thumb  and  back  of 
the  hand  ;  it  ascends  along  the  radial  side  of  the  fore  arm, 
passes  over  the  bend  of  the  elbow,  is  joined  by  the  median 
cephalic,  and  then  ascends  along  the  outside  of  the  arm  to 
the  clavicle.  The  median  vein  arises  by  small  branches 
from  the  forepart  of  the  wrist,  it  ascends  along  the  fore  arm 
between  the  cephalic  and  basilic  veins,  and  near  the  elbow 
divides  into  two  or  three  branches :  first,  the  median  basilic, 
which  ascends  obliquely  over  the  fascia  of  the  biceps  to 
join  the  basilic ;  second,  the  median  cephalic,  which  passes 
obliquely  upwards  and  outwards,  and  joins  the  cephalic 
vein  ;  the  third  branch  of  the  median,  when  present,  sinks 
deep,  and  joins  one  of  the  deep  veins.  The  internal  cuta- 
neous nerve  and  its  branches  accompany  the  basilic  vein, 
some  passing  anterior,  others  posterior  to  it ;  the  external 
cutaneous,  or  musculo-cutaneous,  in  general  lies  behind 
the  cephalic  vein  at  the  bend  of  the  elbow,  its  branches 


DUBLIN    DISSECTOR.  121 

afterwards  twine  around  that  vessel.    The  relation  between 
the  cutaneous  nerves  and  veins  is  liable  to  great  variety. 

The  fascia  of  the  fore  arm  is  very  strong,  particularly  on 
the  posterior  part ;  it  consists  of  tendinous  fibres,  which 
run  in  every  direction,  connected  on  either  side  to  the  con- 
dyles,  and  to  the  muscles  which  are  attached  to  these ;  it 
receives  an  addition  from  the  biceps  before,  and  from  the 
triceps  behind  ;  as  it  descends,  it  invests  the  limb  so  closely 
as  to  give  it  a  certain  form  ;  it  sends  septa  between  the  dif- 
ferent muscles,  which  give  attachment  to  several  fibres, 
and  it  adheres  very  closely  to  the  olecranon  and  to  the  ulna 
its  whole  length  :  inferiorly  it  is  connected  to  the  annular 
ligaments  of  the  carpus.  The  annular  ligaments  of  the  wrist 
appear  formed  in  part  by  this  fascia,  strengthened  by 
proper  transverse  fibres ;  the  posterior  is  attached  to  the 
styloid  process  of  the  ulna  internally,  and  to  that  of  the 
radius  externally ;  it  binds  down  the  extensor  tendons. 
The  anterior  annular  ligament  is  much  stronger ;  it  is  at- 
tached to  the  unciform  and  pisiform  bones  internally,  to 
the  scaphoid  and  trapezium  externally ;  its  upper  edge  is 
connected  to  the  fascia  of  the  fore  arm,  its  lower  to  that  of 
hand :  this  ligament,  together  with  the  carpus,  forms  a 
canal  or  ring  for  the  passage  of  the  flexor  tendons.  The 
integuments  of  the  hand  are  thin  posteriorly,  and  cover 
several  cutaneous  veins ;  anteriorly  they  are  dense,  and 
the  subjacent  cellular  tissue  granulated  and  firm  ;  on  the 
back  of  the  hand  a  very  thin  aponeurosis  exists,  but  ante- 
riorly, there  is  a  remarkable,  strong  fascia,  the  palmar 
fascia:  this  is  of  a  triangular  form,  commences  narrow  at 
the  annular  ligament,  from  which,  and  from  the  tendon  of 
the  palmaris  longus,  it  arises ;  it  then  expands  over  the 
palm  of  the  hand,  and  near  the  fingers  divides  into  four 
fasciculi,  each  of  which  is  forked  and  inserted  into  either 
side  of  each  of  the  sheaths  of  the  flexor  tendons,  and  into 
the  capsular  ligaments  of  the  first  phalanges ;  transverse 
bands  pass  across  these  diverging  fasciculi,  and  several 
fibres  penetrate  between  the  tendons,  and  join  the  meta, 
carpal  bones  and  the  interosseous  muscles;  a  thin  apo- 
neurosis, derived  from  the  outer  edge  of  the  palmar  fascia, 
covers  the  muscles  of  the  thumb,  and  a  similar  one,  those 
of  the  little  finger.  Attached  to  the  palmar  fascia  is  the 
following  small  cutaneous  muscle. 

PALMARIS  BREVIS,  arises  from  the  annular  ligament  and 
from  the  inner  edge  of  the  palmar  fascia ;  the  fibres  pass 
transversely  inwards,  and  are  inserted  by  scattered  fibres 
into  the  integuments  on  the  inner  side  of  the  palm  of  the 
hand.  Use,  to  deepen  the  hollow  of  the  palm  of  the  hand 
by  drawing  the  integuments  towards  the  thumb.  We  have 


122  DUBLIN    DISSECTOR. 

no  analogous  muscle  to  this  in  the  foot.  We  may  now  dis- 
sect off  the  fascia  of  the  hand  and  fore  arm,  to  expose  the 
muscles;  in  some  situations  it  is  difficult  and  unnecessary 
to  separate  this  from  the  muscular  fibres ;  beneath  the 
palmar  fascia  we  expose  the  superficial  palmar  arch  of  ves- 
sels and  nerves  passing  across  the  flexor  tendons  and  the 
lumbricales  muscles. 

The  muscles  of  the  fore  arm  are  so  very  numerous,  that 
it  will  be  found  convenient  to  class  them  according  to  their 
situation  and  their  use.  One  set  of  these  muscles  is  em- 
ployed in  bending  the  fore  arm,  wrist  and  fingers ;  these 
are  the  flexors :  a  second,  nearly  allied  to  these,  have  the 
power  of  pronating  the  hand,  that  is,  of  rolling  the  radius 
across  the  ulna,  so  as  to  make  the  palm  of  the  hand  look 
downwards;  these  are  the  pronators :  a  third  set,  the  exten- 
sors^ can  extend  the  fore  arm,  hand,  and  fingers  ;  and  a 
fourth,  allied  to  these,  the  supinators,  can  turn  the  hand 
supine :  that  is,  place  the  radius  and  ulna  on  the  same 
plane,  and  make  the  palm  of  the  hand  look  upwards.  The 
pronators  and  flexors  arise  chiefly  from  the  internal  con- 
dyle, and  from  the  inner  or  ulnar  side  of  the  fore  arm ; 
each  of  these  divisions  may  be  arranged  into  a  superficial 
and  deep  layer. 

The  pronators  and  flexors  arising  from  the  inner  side  of 
the  fore  arm,  are  eight  in  number :  five  in  the  superficial 
layer,  three  in  the  deep  ;  the  five  superficial  are,  the  prona- 
tor  teres,  flexor  carpi  radialis,  palmaris  longus,  flexor  digi- 
torurn  sublimis,  and  flexor  carpi  ulnaris:  the  three  deep 
muscles  are  the  flexor  digitorum  profundus,  flexor  pollicis 
longus,  and  pronator  quadratus.  In  the  following  descrip- 
tion of  these  muscles,  the  hand  is  supposed  to  be  turned 
forwards,  the  radius  externally,  and  the  ulna  internally. 
The  muscles,  which  arise  from  the  internal  condyle  of  the 
humerus,  are  covered  by  the  fascia  of  the  biceps ;  they 
cannot  be  separated  from  each  other  above,  but  have  a 
common  tendinous  origin  from  the  condyle,  the  fascia,  and 
its  septa,  also  from  the  ulna. 

PRONATOR  RADII  TERES,  arises  tendinous  and  fleshy  from 
the  anterior  part  of  the  internal  condyle,  from  the  fascia 
of  the  fore  arm  and  its  intermuscular  septa ;  also  by  a 
small  tendon  from  the  coronoid  process  of  the  ulna ;  the 
median  nerve  separates  these  origins ;  the  fibres  pass  ob- 
liquely outwards  over  the  radius,  and  are  inserted,  chiefly 
tendinous,  into  the  outer  and  back  part  of  the  radius,  about 
its  centre.  Use,  to  pronate  the  hand,  by  rolling  the  radius 
forwards  and  inwards  over  the  ulna  ;  it  is  also  a  flexor  of 
the  fore  arm :  this  is  the  most  external  of  the  muscles,  aris- 
ing from  the  inner  condyle  ;  it  is  superficial,  except  at  its 


DUBLIN    DISSECTOR.  123 

insertion,  which  is  covered  by  the  supinator  longus,  and  by 
the  radial  vessels  ;  it  lies  inferior  to  the  supinator  brevis : 
this  muscle  forms  the  internal  boundary  of  the  triangular 
hollow  at  the  bend  of  the  elbow,  which  contains  the  tendon 
of  the  biceps,  the  brachial  nerve  and  vessels. 

[Variety.     This  muscle  is  sometimes  double.] 

FLEXOR  CARPI  RADIALIS,  arises  narrow  and  tendinous 
from  the  inner  condyle,  and  fleshy  from  the  intermuscular 
septa ;  it  forms  a  thick  belly,  which  lies  very  superficial, 
and  ends  in  a  prominent  flat  tendon ;  this  descends  ob- 
liquely outwards,  passes  beneath  the  annular  ligament, 
and  is  inserted  into  the  base  of  the  metacarpal  bone  of  the 
index  finger.  Use,  to  bend  the  hand,  and  assist  in  prona- 
ting  it ;  this  muscle  is  overlapped  above  by  the  pronator 
teres,  and  covered  below  by  the  annular  ligament  and  by 
the  muscles  of  the  thumb,  so  that  its  insertion  cannot  be 
seen  until  the  palm  of  the  hand  has  been  dissected ;  it 
arises  and  descends  at  first  between  the  pronator  teres  and 
palmaris  longus,  afterwards  between  this  latter  and  the 
supinator  longus,  from  which  it  is  separated  by  the  radial 
nerve  and  vessels  :  the  radial  edge  of  this  tendon  may  serve 
as  a  guide,  in  cutting  down  on  the  radial  artery  in  the  liv- 
ing subject. 

PALMARIS  LONGUS  arises  by  a  slender  tendon  from  the 
inner  condyle,  and  from  the  fascia  of  the  fore  arm ;  forms 
a  short  belly,  which  ends  in  a  flat  tendon  ;  inserted  near  the 
root  of  the  thumb  into  the  annular  ligament  and  palmar  apo- 
neurosis.  Use,  to  bend  the  hand  and  make  tense  the  palmar 
fascia ;  it  descends  between  the  flexor  carpi  radialis  and  ulna- 
ris,  and  lies  on  the  flexor  sublimis :  it  is  sometimes  wanting. 

[Sometimes  its  fleshy  part  is  in  the  middle,  and  at  other  times  its 
belly  extends  almost  to  the  wrist.] 

FLEXOR  CARPI  ULNARIS,  arises  tendinous  from  the  internal 
condyle,  tendinous  and  fleshy  from  the  inner  side  of  the 
olecranon  process  ;  the  ulnar  nerve  and  posterior  ulnar  re- 
current arteries  separate  these  origins ;  it  also  arises  by  a 
tendinous  expansion  from  the  inner  edge  of  the  ulna  nearly 
its  whole  length,  and  from  the  fascia  of  the  fore  arm,  the 
fibres  pass  obliquely  forwards  to  a  tendon  which  descends 
in  front  of  the  ulna,  and  which  overlaps  the  ulnar  nerve 
and  vessels,  and  is  inserted  into  the  pisiform  bone,  and  by  a 
few  ligamentous  fibres  into  the  base  of  the  fifth  metacarpal 
bone  ;  this  insertion  is  also  connected  to  the  muscles  of  the 
little  finger.  Use,  to  flex  the  hand,  and  adduct  it,  particu- 
larly when  assisted  by  the  extensor  carpi  ulnaris  :  adduc- 
tion of  the  hand  is  not  so  limited  as  abduction,  in  conse- 
quence of  the  ulna  being  shorter  below  than  the  radius. 


124  DUBLIN    DISSECTOR. 

This  muscle  is  superficial,  and  lies  internal  and  rather  pos- 
terior to  the  preceding  muscles ;  it  descends  between  the 
flexor  sublimis  and  extensor  carpi  ulnaris,  and  lies  upon 
the  flexor  profundus ;  the  tendon  passes  over  the  annular 
ligament,  and  is  connected  to  it  by  a  tendinous  slip,  which 
also  passes  over  the  ulnar  artery  and  nerve. 

FLEXOR  DIGITORUM  SUBLIMIS  PERFORATUS,  arises  tendinous 
and  fleshy  from  the  internal  condylc  and  internal  lateral 
ligament ;  tendinous  from  the  coronoid  process,  and  fleshy 
from  the  radius  below  its  tubercle,  internal  to  the  pronator 
teres,  and  between  the  supinator  breyis  and  flexor  pollicis 
longus :  it  forms  a  large  muscle,  which  ends  in  four  ten- 
dons ;  these  descend,  two  anterior,  for  the  middle  and  ring 
finger ;  and  two  posterior,  for  the  index  and  little  finger  ; 
they  all  pass  beneath  the  annular  ligament,  and  proceed 
along  the  palm  of  the  hand,  superficial  to  the  deep  flexor 
tendons,  and  beneath  the  palmar  fascia :  and  at  the  first 
phalanx  of  each  finger,  or  opposite  the  head  of  each  me- 
tacarpal  bone,  each  of  these  tendons  becomes  enclosed  in 
a  strong  sheath,  with  one  of  the  deep  flexors ;  this  sheath 
is  continued  to  the  anterior  extremity  of  the  second  pha- 
lanx. Near  the  end  of  the  first  phalanx,  each  of  the  su- 
perficial flexor  tendons  is  split  for  the  passage  of  the 
tendon  of  the  deep  flexor,  which  is  continued  on  to  the 
last  or  ungual  phalanx ;  while  the  divisions  of  each  of  the 
superficial  tendons  become  somewhat  twisted,  that  is,  their 
inner  or  opposed  edges  are  everted  or  folded  out  beneath 
the  deep  flexor,  so  as  to  lie  nearer  to  the  bone,  and  arc 
inserted  into  the  anterior  part  of  the  second  phalanx.  Use, 
to  flex  the  second  joint  of  each  finger  on  the  hand,  the 
hand  on  the  fore  arm,  and  the  latter  on  the  arm.  The 
origin  of  this  muscle  is  partly  concealed  by  the  three  first 
described  muscles,  which  arise  from  the  internal  condyle, 
and  to  which  it  is  connected  by  the  intermuscular  septa ; 
inferiorly  a  portion  of  it  is  superficial  between  the  flexor 
carpi  ulnaris  and  palmaris  longus.  The  tendons  of  this 
muscle  are  enveloped  in  a  large  bursa  behind  the  annular 
ligament;  this  carpal  bursa  is  connected  anteriorly  to  the 
annular  ligament,  posteriorly  to  the  carpus,  is  expanded 
around  the  superficial  and  deep  flexor  tendons,  the  medi- 
an nerve,  and  the  tendon  of  the  flexor  pollicis  longus,  and 
ends  above  arid  below  in  a  cul  dt  sac,  each  end  of  which 
extends  beyond  the  edges  of  the  annular  ligament. 

[This  bursa  is  the  seat  of  that  affection  called  ganglion,  in  which 
the  bursa  forms  a  sort  of  hour  glass  tumour,  one  globe  projecting  into 
the  palm  of  the  hand,  the  other  on  the  fore  part  of  the  wrist  and  the 
middle  being  constricted  by  the  annular  ligament ;  on  opening  this 
tumom  it  may  be  found  filled  with  serum,  either  thin  and  watery,  or 


DUBLIN    DISSECTOR.  125 

very  albuminous ;  or  with  a  substance  resembling  rice  water ;  or  in 
more  rare  cases  with  a  great  number  of  small  and  distinct  bodies 
like  grains  of  barley.  In  the  only  case  of  this  kind  which  we  have  met 
with,  there  was  very  little  fluid,  and  none  of  the  ordinary  fluctuation, 
but  an  albuminous  crepitus  or  grating  sound,  such  as  is  sometimes 
heard  in  inflammation  around  joints  after  contusions  :  the  rationale 
of  cure  in  all  these  cases,  is  to  effect  an  obliteration  of  the  sac,  by 
adhesive  inflammation.] 

In  the  palm  of  the  hand  the  tendons  of  the  flexor  subli- 
mis  are  covered  by  the  integuments,  palmar  fascia,  and 
the  superficial  palmar  arch  of  vessels  and  nerves ;  along 
the  fingers  each  tendon  is  enclosed  in  a  strong  fibrous 
sheath,  which  is  continued  to  the  end  of  the  second  pha- 
lanx of  each  finger  ;  this  sheath,  together  with  the  anterior- 
surface  of  the  phalanges,  forms  a  complete  canal  or  tube, 
which,  half  fibrous  and  half  osseous,  is  lined  by  a  syno- 
vial  membrane,  which  forms  a  cul  de  sac  at  either  extremi- 
ty ;  being  reflected  over  the  tendons  it  encloses,  and  form- 
ing several  folds  or  frasna  to  connect  these  tendons  to  this 
canal :  this  sheath  is  weak,  opposite  each  articulation, 
but  is  very  strong  on  the  phalanges ;  its  anterior  extremi- 
ty is  continuous  with  the  insertion  of  the  deep  flexor 
tendon. 

[  Varieties.  The  tendon  to  the  little  finger  is  sometimes  wanting, 
and  supplied  by  the  flexor  profundus ;  the  portion  of  the  muscle  going 
to  the  fore  finger,  is  sometimes  so  distinct,  as  to  appear  like  a  sepa. 
rate  muscle.] 

Divide  the  flexor  sublimis  and  carpi  radialis,  and  the 
three  deep  muscles  will  be  partially  exposed, — namely, 
the  flexor  digitoruna  profundus,  flexor  pollicis  longus,  and 
nearly  concealed  by  .these,  the  pronator  quadratus. 

FLEXOR  DIGITORUM  PROFUNDUS  PERFORANS,  arises  fleshy 
from  three  superior  fourths  of  the  anterior  surface  of  the 
ulna,  and  from  the  internal  half  of  the  interosseous  liga- 
ment ;  it  sometimes  receives  a  small  slip  from  the  radius 
below  its  tubercle ;  it  forms  a  thick  muscle  which  descends 
along  the  middle  and  ulnar  side  of  the  fore  arm,  and  ends 
in  four  flat  tendons ;  these  pass  beneath  the  annular  liga- 
ment, enter  the  ligamentous  sheaths  on  the  fingers,  pass 
through  the  slits  in  the  superficial  flexor  tendons,  and  are 
inserted  into  the  last  phalanx  of  each  finger.  Use,  to  bend 
the  last  phalanx  and  to  co-operate  with  the  superficial 
flexor  muscle  in  bending  the  other  phalanges  and  the 
wrist ;  this  muscle  is  covered  by  those  of  the  superficial 
layer,  which  have  been  described ;  the  ulnar  vessels,  the 
median  and  ulnar  nerves  also  descend  along  it ;  and  it 
covers  the  ulna,  the  interosseous  ligament  and  vessels,  the 
11* 


126  DUBLIN    DISSECTOR. 

pronator  quadratus  and  the  carpus,  and  on  each  finger  its 
tendon  is  superficial  to  that  of  the  flexor  sublimis. 

[Variety.  There  is  sometimes  a  fasciculus  uniting  the  tendon 
going  to  the  fore  finger,  with  the  flexor  longus  pollicis.] 

FLEXOR  POLLICIS  LONGUS,  arises  from  the  forepart  of  the 
radius,  commencing  narrow  just  below  its  tubercle,  and 
from  the  interosseous  membrane,  to  within  about  two 
inches  of  the  carpus,  it  also  very  frequently  arises  by  a 
long  and  narrow  tendinous  and  fleshy  slip  from  the  coro- 
noid  process  ;  this  at  first  looks  like  a  distinct  muscle  ;  all 
the  fibres  descend  obliquely  forwards  to  a  tendon,  which 
passes  beneath  the  annular  ligament,  and  then  runs  out- 
wards between  the  two  portions  of  the  short  flexor,  and 
the  two  sesamoid  tubercles  at  the  extremity  of  the  meta- 
carpal  bone ;  it  next  enters  a  strong  ligamentous  sheath, 
and  is  confined  by  it  as  far  as  the  last  phalanx  of  the 
thumb,  into  the  middle  of  which  it  is  inserted.  Use,  to  flex 
and  adduct  the  different  joints  of  the  thumb  upon  the  hand, 
and  the  latter  upon  the  fore  arm.  This  muscle  is  covered 
by  the  flexor  sublimis  and  radialis,  and  by  the  radial  ves- 
sels, and  inferiorly  by  the  annular  ligament,  it  descends 
along  the  radial  side  of  the  flexor  profundus. 

PRONATOR  QUADRATUS,  is  exposed  by  separating  the  flexor 
pollicis  and  profundus ;  it  is  a  small  square  muscle  situat- 
ed just  above  the  carpus,  and  arises  tendinous  and  fleshy 
from  the  inferior  fifth  of  the  anterior  surface  of  the  ulna ; 
the  fibres  pass  transversely  outwards,  descend  a  little,  and 
are  inserted  into  the  anterior  part  of  the  inferior  fourth  of 
the  radius.  Use,  to  roll  the  radius  over  the  ulna,  and  so 
to  pronate  the  hand :  this  muscle  is  covered  by  the  ten- 
dons of  the  preceding,  and  by  the  ulnar  and  radial  vessels, 
and  it  lies  on  the  interosseous  ligament,  the  radius  and  the 
ulna. 

[Variety.     This  muscle  is  sometimes,  though  rarely,  wanting.] 

The  muscles  which  are  situated  on  the  outer  and  back 
part  of  the  fore  arm  are  supinators  and  extensors,  and  are 
also  arranged  into  two  layers,  a  superficial  and  deep  ;  the 
superficial  consists  of  seven,  namely,  supinator  radii  lon- 
gus, extensor  carpi  radialis  longus,  and  brevis,  extensor 
digitorum  communis,  extensor  minimi  digiti,  extensor  car- 
pi ulnaris  and  anconrcus  ;  these  muscles  arise  more  dis- 
tinctly than  those  on  the  internal  side  of  the  arm  :  some 
of  them  however,  particularly  those  on  the  ba.ck  part,  are 
closely  connected  to  each  other,  arising  in  common  from 
the  external  condyle  of  the  humerus,  from  the  posterior 
surface  of  the  radius  and  ulna,  the  intermuscular  ligaments 


DUBLIN     DISSECTOR.  127 

and  the  fascia,  which  is  partly  derived  from  the  tendon  of 
the  triceps. 

SUPINATOR  RADII  LONGUS,  forms  the  prominence  along 
the  outer  and  anterior  part  of  the  fore  arm,  arises  tendinous 
and  fleshy  from  the  external  ridge  of  the  humerus,  com- 
mencing a  little  below  the  deltoid  and  continuing  to  with- 
in about  two  inches  of  the  outer  condyle;  it  also  arises 
from  the  intermuscular  ligament,  which  separates  it  from 
the  second  or  outer  head  of  the  triceps,  between  which  and 
the  brachialis  anticus  this  muscle  is  situated.  The  supi- 
nator  longus  descends  along  the  outer  and  anterior  part  of 
the  elbow,  and  about  the  middle  of  the  fore  arm  ends  in  a 
flat  tendon,  which  descends  along  the  radius,  and  is  inserted 
into  a  rough  surface  on  the  outside  of  that  bone,  near  its 
styloid  process.  Use,  to  roll  the  radius  backwards,  so  as 
to  make  the  hand  look  supine  ;  it  can  also  bend  the  elbow 
joint.  This  muscle  is  superficial ;  it  passes  over  the  ex- 
tensor carpi  radialis  longus  above,  the  tendon  of  the  pro- 
nator  teres  in  the  middle,  and  the  radius  inferiorly  ;  its  ten- 
don descends  at  first  between  the  pronator  teres  and  ex- 
tensor radialis  longus,  afterwards  between  the  latter  and 
that  of  the  flexor  carpi  radialis ;  at  its  insertion  it  is  cross- 
ed by  the  extensor  tendons  of  the  thumb.  This  muscle 
and  its  tendon  overlap  the  radial  nerve  and  vessels ;  its 
ulnar  edge,  therefore,  will  serve  as  a  guide  to  the  latter,  in 
case  we  are  required,  during  life,  to  expose  them,  in  order 
to  tie  a  ligature  around  the  radial  artery. 

EXTENSOR  CARPI  RADIALIS  LONGUS,  arises  tendinous  and 
fleshy  from  the  ridge  on  the  external  side  of  the  humerus, 
between  the  supinator  longus  and  the  external  condyle ; 
it  forms  a  thick  short  belly  which  passes  over  the  outside 
of  the  joint,  ends  in  a  flat  tendon,  which  descends  along 
the  outer  and  back  part  of  the  radius,  runs  through  a 
groove  on  its  lower  extremity,  and  passing  over  the  wrist 
joint,  is  inserted  into  the  back  part  of  the  carpal  end  of  the 
metacarpal  bone  of  the  index  finger,  nearly  opposite  to 
that  of  the  flexor  carpi  radialis.  Use,  it  extends  the  wrist, 
bends  the  hand  backwards,  and  abducts  it  a  little ;  it  may 
also  assist  in  bending  the  elbow  joint ;  its  belly  is  covered 
by  the  last  described  muscle,  but  projects  behind  it ;  the 
tendon  descends  behind  that  of  the  supinator  longus,  and 
passes  beneath  the  extensors  of  the  thumb  and  the  annular 
ligament ;  it  covers  the  supinator  brevis  and  the  following 
muscle. 

[Varieties.  This  muscle  is  also  sometimes  inserted  into  the  third 
metacarpal  bone  by  a  distinct  slip  ;  sometimes  this  muscle  and  the 
next,  are  so  blended,  as  to  appear  common.] 

EXTENSOR  CARPI  RADIALIS  BREVIS,  arises  tendinous  and 


128  DUBLIN    DISSECTOR. 

fleshy  from  the  inferior  and  posterior  part  of  the  external 
condyle,  and  from  the  external  lateral  ligament,  forms  a 
thick  belly,  which  descends  along  the  back  part  of  the  ra- 
dius, ends  in  a  flat  tendon,  which  runs  through  the  same 
groove  as  the  tendon  of  the  last  muscle,  internal  to  which 
it  lies ;  passes  also  beneath  the  annular  ligament,  and  is 
inserted  into  the  carpal  extremity  of  the  third  metacarpal 
bone,  or  that  of  the  middle  finger.  Use,  similar  to  that  of 
the  last ;  it  is  covered  superiorly  by  the  last  described 
muscle,  and  by  the  supinator  longus,  and  below  by  the 
tendons  of  the  extensor  muscles  of  the  thumb,  and  by  that 
of  the  last  muscle,  and  by  the  skin ;  it  covers  the  supinator 
brevis  and  the  insertion  of  the  pronator  teres. 

EXTENSOR  DIGJTORUM  COMMUNIS,  is  situated  more  towards 
the  back  part  of  the  fore  arm  than  the  last  described  mus- 
cles ;  it  arises  in  common  with  the  last,  and  with  the  exten- 
sor minimi  digiti  from  the  external  condyle,  the  fascia,  and 
its  intermuscular  processes,  also  from  the  ulna;  it  de- 
scends along  the  back  of  the  fore  arm,  and  about  the  mid- 
dle of  the  latter  ends  in  four  tendons,  which  pass  under  the 
annular  ligament  in  a  groove  in  the  radius,  extend  along 
the  back  of  the  hand,  expanding  as  they  approach  the  four 
fingers,  into  all  the  phalanges  of  which  they  are  inserted  by 
a  tendinous  expansion.  Use,  to  extend  all  the  joints  of  the 
fingers,  also  the  carpus  ;  this  muscle  arises  between  the 
extensor  carpi  radialis  brevis  and  extensor  minimi  digiti ; 
it  descends  superficially  between  these,  and  over  the  supi- 
nator brevis  and  extensors  of  the  thumb  ;  on  the  back  of 
the  hand  the  tendons  are  connected  to  each  other  by  cross 
slips  ;  that  which  goes  to  the  ring  finger  is  the  largest ;  all 
the  tendons,  as  they  approach  the  base  of  the  first  phalanx, 
become  thick  but  narrow ;  afterwards  they  enlarge  and 
are  joined  by  the  tendons  of  the  lumbricales  and  interos- 
sei ;  at  the  articulation  of  the  first  and  second  phalanx 
each  divides  into  three  bands  ;  the  middle  one  is  inserted 
into  the  posterior  surface  of  the  second  phalanx  ;  the  late- 
ral pass  along  the  sides  of  this  articulation ;  they  after- 
wards converge  and  unite  in  a  flat  tendon,  which  is  insert- 
ed into  the  base  of  the  last  or  third  phalanx.  The  back 
part  of  all  the  fingers  is  covered,  as  far  as  the  last  phalanx, 
by  a  tendinous  expansion,  derived  from  these  tendons,  and 
from  those  of  the  lumbricales  and  interossei  muscles. 

[  Variety.  This  muscle  sometimes  sends  a  double  tendon  to  the 
little  finger.] 

EXTENSOR  CARPI  ULNARIS  is  very  superficial,  arises  ten- 
dinous and  fleshy  between  the  extensor  minimi  digiti  and 
anconoeus,  from  the  external  condyle,  fascia  and  intermus- 


DUBLIN*    DISSECTOR.  129 

cular  septa ;  descends  obliquely  inwards,  between  the 
flexor  ulnaris  and  extensor  minimi  digiti,  towards  the  ulna, 
and  receives  an  addition  from  it ;  it  ends  in  a  strong  ten- 
don,  which  runs  through  a  groove  on  the  back  of  the  ulna, 
beneath  the  annular  ligament,  and  is  inserted  into  the  car- 
pal end  of  the  fifth  metacarpal  bone.  Use,  to  extend  the 
hand  and  bend  it  backwards  :  also  to  adduct  it,  that  is,  flex 
it  laterally  towards  the  ulna. 

[Variety.  Sometimes  the  tendon  of  this  muscle  is  united  to  the 
extensor  muscle  of  the  little  finger.] 

ANCONJEUS,  small,  triangular,  and  placed  at  the  outer  side 
of  the  olecranon,  beneath  the  skin ;  arises  narrow  and 
fleshy  from  the  posterior  and  inferior  part  of  the  external 
condyle  and  lateral  ligament,  forms  a  thick  triangular 
mass,  which  adheres  to  the  synovial  membrane  and  de- 
scends obliquely  inwards,  to  be  inserted  into  the  external 
surface  of  the  olecranon,  and  about  the  superior  fifth  of 
the  posterior  surface  of  the  ulna.  Use,  to  extend  the  fore 
arm  on  the  arm,  and  to  raise  the  synovial  membrane  out 
of  the  articulation ;  this  muscle  is  partly  covered  by  the 
tendon  and  aponeurosis  of  the  triceps ;  the  remainder  of 
it  is  superficial ;  it  is  situated  between  the  olecranon  and 
the  extensor  carpi  ulnaris ;  it  often  appears  as  a  continua- 
tion of  the  triceps ;  it  covers  a  portion  of  the  elbow  joint 
and  of  the  supinator  brevis. 

EXTENSOR  MINIMI  DIGITI,  vel  AURICULAKIS,  arises  in  com- 
mon with  the  extensor  communis,  and  descends  between  it 
and  the  extensor  carpi  ulnaris ;  it  forms  a  small  fleshy 
belly,  which  descends  very  obliquely  inwards,  and  ends  in 
a  slender  tendon  ;  this  passes  through  a  separate  groove  in 
the  radius,  and  also  through  a  distinct  division  of  the  an- 
nular ligament,  in  which  situation  it  is  frequently  found 
divided  into  two,  which  continue  in  contact,  and  afterwards 
unite ;  this  tendon  becomes  attached  to  the  fourth  tendon 
of  the  extensor  communis,  and  is  inserted  along  with  it  into 
the  posterior  part  of  the  phalanges  of  the  little  finger. 
Use,  to  assist  the  extensor  communis,  and  to  extend  and 
abduct  the  little  finger  independent  of  the  others. 

The  deep  muscles  in  this  situation  are  five  in  number, 
they  will  be  exposed  by  removing  the  superficial  layer ; 
they  consist  of  the  supinator  radii  brevis,  three  extensors 
of  the  thumb,  and  the  indicator. 

SUPINATOR  RADII  BREVIS,  short  and  flat,  surrounds  the 
upper  part  of  the  radius,  arises  from  the  external  condyle, 
external  lateral  and  coronary  ligaments,  and  from  a  ridge 
on  the  outer  side  of  the  ulna,  which  commences  below  its 
lesser  sigmoid  cavity  ;  the  fibres  adhere  to  the  capsular 


130  DUBLIN    DISSECTOR. 

ligament,  and  descend  obliquely  outwards  and  forwards 
round  the  upper  part  of  the  radius,  and  are  inserted  into 
the  upper  third  of  the  external  and  anterior  surface  of  this 
bone,  from  above  its  tubercle  down  to  the  insertion  of  the 
pronator  teres.  Use,  to  turn  the  radius  outwards,  so  as  to 
make  the  hand  look  supine  ;  it  can  also  assist  in  extending 
the  fore  arm.  This  muscle  nearly  surrounds  the  upper 
part  of  the  radius,  it  is  covered  by  the  supinator  longus, 
the  radial  extensors  of  the  carpus,  and  the  extensor  digito- 
rum  communis  externally  ;  by  the  anconseus  and  extensor 
ulnaris  posteriorly  ;  and  anteriorly  by  the  radial  nerve  and 
vessels,  and  by  the  brachialis  and  biceps ;  it  partly  sur- 
rounds the  humeral  and  ulnar  articulations  of  the  radius ; 
its  anterior  edge  is  notched  above  for  the  insertion  of  the 
biceps,  and  is  overlapped  by  the  pronator  teres  below. 

[Variety.     This  muscle  is  sometimes  double.] 

EXTENSOR  Ossis  METACARPI  POLLICIS,  or  ABDUCTOR  POL- 
LICIS  LONGUS,  arises  fleshy  from  the  middle  of  the  posterior 
part  of  the  ulna,  below  the  anconseus,  also  from  the  inter- 
osseous  ligament  and  posterior  surface  of  the  radius  below 
the  supinator  brevis ;  it  descends  outwards  and  forwards, 
and  ends  in  a  tendon,  which  passes  through  a  groove  on 
the  outside  of  the  lower  end  of  the  radius,  runs  by  the  side 
of  the  carpus,  and  is  inserted  in  general  by  two  tendons, 
one  into  the  os  trapezium,  and  the  other  into  the  upper  and 
back  part  of  the  metacarpal  bone  of  the  thumb.  Use,  to 
extend  the  first  joint  of  the  thumb,  and  separate  it  from 
the  fingers;  it  also  extends  the  wrist,  and  abducts  the 
hand  ;  it  can  also  assist  in  supination.  The  origin  of  this 
muscle  is  concealed  by  the  extensor  communis  and  carpi 
ulnaris ;  the  tendon  is  superficial  and  passes  over  the  ten- 
dons of  the  radial  extensors  of  the  carpus,  also  over  the 
radial  vessels. 

[Variety.     This  muscle  is  sometimes  double.] 

EXTENSOR  PRIMI  INTERNODII  POLLICIS,  or  EXTENSOR  MINOR, 
arises  from  the  back  part  of  the  ulna,  below  its  middle,  and 
from  the  interosseous  ligament  and  radius;  it  descends 
along  the  ulnar  side  of  the  last  muscle  ;  its  tendon  passes 
through  the  same  groove  in  the  radius,  is  bound  down 
by  the  same  portion  of  the  annular  ligament,  and  is  insert- 
ed into  the  posterior  part  of  the  first  phalanx;  a  small  slip 
is  often  continued  on  to  the  second  phalanx.  Use,  to  ex- 
tend the  second  joint  of  the  thumb,  and  to  assist  the  last 
described  muscle  ;  its  connexions  are  also  similar. 

[Varieties.  This  muscle  is  sometimes  an  appendage  of  the  last, 
and  sometimes  confounded  with  the  next  muscle.] 

EXTENSOR   SECUNDI    INTERNODII   POLLICIS,   or    EXTENSOR 


DUBLIN    DISSECTOR.  131 

MAJOR,  arises  from  the  posterior  surface  of  the  ulna  above 
its  centre,  and  from  the  interosseous  membrane ;  its  belly 
overlaps  the  two  former  muscles,  its  tendon  passes  along 
a  distinct  groove  in  the  radius,  runs  over  the  outer  side  of 
the  wrist,  the  metacarpal  bone  and  first  phalanx  of  the 
thumb,  and  is  inserted  into  the  posterior  part  of  the  second 
or  last  phalanx.  Use,  to  extend  the  last  phalanx  of  the 
thumb  upon  the  first,  and  to  assist  the  former  muscles  in 
extending  and  supinating  the  hand.  The  tendon  of  this 
muscle  is  separated  from  the  two  former,  on  the  outer  and 
back  part  of  the  wrist,  by  a  considerable  interval,  in  which 
we  perceive  the  tendons  of  the  radial  extensors  of  the  car- 
pus, and  the  radial  artery  ;  the  relations  of  this  muscle  in 
other  respects  are  nearly  similar  to  those  of  the  other  ex- 
tensors of  the  thumb. 

EXTENSOR  INDICIS,  or  INDICATOR,  arises  from  the  middle 
of  the  posterior  surface  of  the  ulna  and  interosseous  mem- 
brane ;  its  tendon  passes  under  the  annular  ligament  along 
with  those  of  the  common  extensor,  is  attached  to  the  ra- 
dial side  of  that  tendon  which  belongs  to  the  fore  finger, 
and  is  inserted  along  with  it  into  its  second  and  third  pha- 
langes. Use,  it  assists  the  common  extensor,  or  produces 
the  extension  of  the  fore  finger  alone,  as  in  pointing.  This 
muscle  is  concealed  by  the  extensor  communis  and  ulna- 
ris,  lies  to  the  ulnar  side  of  the  extensor  pollicis  major, 
and  its  tendon  passes  under  those  of  the  common  extensor, 
to  which  it  is  sometimes  connected  by  a  tendinous  slip. 

[Varieties.  This  muscle  sometimes  has  two  bellies,  sometimes  it 
is  double,  and  the  second  muscle  goes  to  the  middle  finger.] 

Next  dissect  the  muscles  of  the  hand  ;  first,  those  in  the 
palm,  which  consist,  externally,  of  the  muscles  of  the 
thumb  ;  internally,  of  those  of  the  little  finger,  and  in  the 
middle  of  the  lumbricales  superficially,  and  the  anterior 
interosssei,  deep  seated. 

The  short  muscles  of  the  thumb  are  five  in  number,  viz. 
the  abductor,  opponens,  flexor  brevis,  adductor  pollicis, 
and  abductor  indicis. 

ABDUCTOR  POLLICIS,  arises  broad  and  thin  from  the  ante- 
rior part  of  the  annular  ligament,  os  naviculare  and  trap- 
ezium, inserted  into  the  outside  of  the  base  of  the  first  pha- 
lanx, and  by  an  expansion  into  the  back  of  both  phalan- 
ges ;  its  name  implies  its  use,  to  separate  the  thumb  from 
the  fingers  ;  it  lies  superficial,  and  is  most  external  of  these 
small  muscles,  which  form  the  ball  of  the  thumb. 

OPPONENS  POLLICIS,  or  FLEXOR  Ossis  METACARPI,  arises 
from  the  annular  ligament  and  os  naviculare  ;  inserted  into 
the  anterior  extremity  of  the  metacarpal  bone  of  the  thumb. 


132  DUBLIN    DISSECTOR. 

Use,  to  approximate  the  thumb  to  the  fingers  ;  it  is  internal 
to  and  partly  overlapped  by  the  last  muscle ;  it  lies  on  a 
part  of  the  annular  ligament,  and  of  the  following  muscle, 
from  which  it  is  separated  with  difficulty. 

FLEXOR  POLLICIS  BREVIS,  consists  of  two  portions,  between 
which  is  the  tendon  of  the  flexor  longus  ;  one  head,  the  ex- 
ternal or  anterior,  arises  from  the  inside  of  the  annular  liga- 
ment, and  from  the  trapezium  and  scaphoid  bones,  passes 
outwards,  and  is  inserted  into  the  external  sesamoid  bone  or 
cartilage  and  base  of  the  first  phalanx  of  the  thumb ;  the 
second,  or  internal  or  posterior,  arises  from  the  os  magnum, 
and  the  base  of  the  metacarpal  bone  of  the  middle  finger ; 
it  also  passes  outwards,  distinct  from  the  other  at  first,  but 
afterwards  united  to  it,  and  is  inserted  into  the  internal  sesa- 
moid bone,  and  base  of  the  first  phalanx.  Use,  to  flex  the 
first  phalanx  and  metacarpal  bone  on  the  carpus ;  this  mus- 
cle is  concealed  by  the  two  former,  and  by  the  first  lum- 
bricalis ;  it  covers  the  two  first  interossei  muscles,  and  the 
tendon  of  the  flexor  carpi  radialis ;  its  outer  edge  is  con- 
nected to  the  opponens  pollicis,  and  the  internal  to  the  ad- 
ductor. 

ADDUCTOR  POLLICIS,  triangular  and  broad,  arises  fleshy 
from  three-fourths  of  the  anterior  surface  of  the  third  meta- 
carpal bone,  or  that  of  the  middle  finger,  the  fibres  pass  out- 
wards over  the  second  metacarpal  bone,  and  converging  are 
inserted  into  the  inner  side  of  the  root  of  the  first  phalanx 
of  the  thumb,  along  with  part  of  the  last  muscle ;  its  name 
denotes  its  use.  This  muscle  at  its  origin  is  covered  ante- 
riorly by  the  deep  flexor  tendons  and  by  the  lumbricales ; 
its  insertion  is  covered  by  the  following  muscle,  which  may 
be  best  seen  from  behind. 

ABDUCTOR  INDICIS,  is  also  triangular,  is  situated  between 
the  thumb  and  index  finger,  and  is  best  seen  on  the  poste- 
rior aspect  of  the  hand.  Arises  tendinous  and  fleshy  from 
the  metacarpal  bone  of  the  fore  finger,  and  from  one-half 
of  that  of  the  thumb ;  its  fibres  extend  obliquely  inwards 
and  forwards,  end  in  a  tendon  which  passes  by  the  outer 
side  of  the  first  joint  of  the  fore  finger,  and  is  inserted  into 
the  outer  side  of  the  base  of  its  first  phalanx.  Use,  to  sepa- 
rate the  fore  finger  from  the  others,  or  to  adduct  the  thumb. 
This  muscle  is  superficial  posteriorly  ;  anteriorly  it  is  cover- 
ed by  that  last  described ;  the  radial  artery  passes  between 
its  two  heads  or  origins :  this  muscle  is  similar  to,  and  may 
be  regarded  as  one  of  the  posterior  interossei ;  like  these 
also,  its  insertion  joins  that  of  the  common  extensor  tendon. 
In  the  middle  of  the  palm  of  the  hand  are  seen  four  small 
muscles. 

LUMBRICALES,  are  four  in  number;  they  arise  from  the 


DUBLIN    DISSECTOR.  133 

outer  or  radial  side  of  the  tendons  of  the  flexor  profundus, 
near  the  carpus,  a  little  beyond  the  annular  ligament ;  they 
each  form  a  small  fleshy  belly,  which  ends  in  a  tendon ; 
this  runs  along  the  radial  side  of  the.  finger,  joins  the  tendon 
of  the  corresponding  interosseous  muscle,  and  is  inserted 
about  the  middle  of  the  first  phalanx  into  the  tendinous  ex- 
pansion which  covers  the  back  part  of  each  finger.  Use,  to 
assist  in  bending  the  first  joint  of  the  finger ;  they  cannot 
do  so  unless  the  flexors  are  tense ;  they  can  also  adduct  and 
abduct  the  fingers,  and  when  the  common  extensor  muscle 
is  in  action,  they  may  assist  in  extending  them  ;  these  small 
muscles  are  covered  by  the  superficial  flexor  tendons,  pal- 
mar vessels  and  nerves :  the  first  is  the  largest,  the  fourth 
the  smallest;  the  two  middle  run  nearly  parallel,  but  the 
internal  and  external  diverge :  the  tendons  of  the  lumbri- 
cales  frequently  divide  into  two  portions ;  one  of  these  will 
be  inserted  into  the  first  phalanx,  the  other  into  the  posterior 
tendinous  expansion. 

Variety.  One  of  these  muscles  is  sometimes  wanting  :  sometimes 
one  or  more  is  double,  and  then  the  accessory  is  sent  to  the  ulnar  side 
of  the  adjoining  finger.] 

On  the  inner  side  of  the  palm  of  the  hand  are  the  short 
muscles  of  the  little  finger,  which  are  three  in  number. 

ABDUCTOR  MINIMI  DIGITI,  arises  fleshy  from  the  annular 
ligament  and  from  the  pisiform  bone ;  its  fibres  run  along 
the  ulnar  side  of  the  metacarpal  bone,  and  are  inserted  ten- 
dinous into  the  ulnar  side  of  the  first  phalanx ;  its  name  im- 
plies its  use ;  it  is  superficial ;  a  few  fibres  of  the  palmaris 
only  cover  it ;  its  origin  is  partly  continous  with  the  inser- 
tion of  the  flexor  carpi  ulnaris. 

FLEXOR  BREVIS  MINIMI  DIGITI,  arises  from  the  annular  liga^ 
ment  and  unciform  bone,  inserted  by  a  round  tendon  into  the 
base  of  the  first  phalanx  of  the  little  finger.  Use,  to  flex  and 
adduct  the  little  finger ;  it  lies  to  the  radial  side  of  the  last 
muscle,  along  with  which  it  is  inserted. 

[Variety.     This  muscle  is  sometimes  wanting.] 

ADDUCTOR,  or  OPPONENS  MINIMI  DIGITI,  arises  along  with, 
but  internal  to  the  last,  and  overlapped  by  it,  and  is  inserted 
into  all  the  metacarpal  bone  of  this  finger :  its  name  de- 
notes its  use. 

When  all  the  flexor  and  extensor  tendons  have  been  re- 
moved, we  observe  the  intervals  between  the  metacarpal 
bones  to  be  filled  by  muscular  fibres,  which  are  called  the 
interosseous  muscles ;  they  are  divided  into  two  planes,  a  pos- 
terior and  an  anterior.  The  INTEROSSEI  ANTICI,  or  INTERNI 
or  PALM  ARES,  are  four  in  number ;  they  arise  from  the  sides 
of  the  metacarpal  bones,  and  are  inserted  into  the  first  pha- 

12 


134  DUBLIN    DISSECTOR. 

langes,  and  into  the  tendinous  expansion  which  covers  the 
dorsum  of  each  finger :  the  first  or  prior,  or  externus  indicis, 
arises  from  the  radial  side  of  the  second  metacarpal  bone^ 
and  is  inserted  into  the  external  side  of  the  first  phalanx  of 
the  fore  finger.  Use,  to  adduct  the  fore  finger ;  the  second 
or  posterior,  or  internus,  or  adductor  indicis,  arises  from  the 
ulnar  side  of  the  second  metacarpal  bone,  and  is  inserted  into 
the  inner  side  of  the  first  phalanx  of  the  fore  finger ;  third 
or  prior,  or  externus  or  adductor  annularis,  arises  from  the 
radial  side  of  the  fourth  metacarpal  bone,  and  is  inserted  into 
the  external  side  of  the  first  phalanx  of  the  ring  finger.  Use, 
to  draw  the  ring  finger  towards  the  thumb ;  the  fourth,  or 
interosseous  minimi  digiti,  arises  from  the  radial  side  of  the 
fifth  metacarpal  bone,  and  is  inserted  into  the  outside  of  the 
first  phalanx  of  the  little  finger.  Use,  to  draw  the  little 
finger  towards  the  thumb. 

The  POSTERIOR  or  DORSAL  INTEROSSEI,  are  seen  on  the 
back  part  of  the  hand ;  they  are  longer  than  the  anterior ; 
they  each  arise  by  two  sets  of  fibres  from  the  opposed  sides 
of  two  metacarpal  bones,  and  are  inserted  into  the  base  of 
the  first  phalanx  of  each  finger,  and  into  the  posterior  ten- 
dinous expansion ;  the  first,  or  prior,  or  externus  medii,  arises 
from  the  second  and  third  metacarpal  bones,  fills  the  space 
between  these  two,  and  is  inserted  into  the  outer  side  of  the 
base  of  the  first  phalanx  of  the  middle  finger.  Use,  to  draw 
the  middle  finger  towards  the  thumb  ;  the  second  or  internus 
medii  is  situated  between  the  metacarpal  bones  of  the  mid- 
dle and  ring  finger,  and  is  inserted  into  the  inner  side  of  the 
first  phalanx  of  the  middle  finger.  Use,  to  draw  the  middle 
towards  the  ring  finger ;  the  third,  or  externus  annularis,  is 
between  the  fourth  and  fifth  metacarpal  bones ;  and  is  in- 
serted into  the  inner  side  of  the  ring  finger.  Use,  to  draw 
the  ring  finger  inwards.  All  these  muscles  can  also  extend 
the  fingers.  Some  consider  the  dorsal  interossei  as  four  in 
number,  making  the  abductor  indicis  the  first  of  this  class. 

In  the  dissection  of  the  fore  arm  and  hand  we  meet  with 
the  branches  of  the  brachial  artery,  with  their  accompany- 
ing veins ;  also  branches  of  the  brachial  plexus  of  nerves : 
the  cutaneous  veins  have  been  already  noticed.  The  bra- 
chial artery,  when  it  arrives  at  the  bend  of  the  elbow,  di- 
vides into  its  radial  and  ulnar  branches.  The  radial  artery 
descends  from  the  elbow  obliquely  outwards,  to  the  styloid 
process  of  the  radius,  passes  over  the  outer  side  of  the  carpus, 
and  then  between  the  metacarpal  bones  of  the  thumb,  and 
of  the  fore  finger,  where  it  divides  into  three  branches, 
radialis  indicis,  magna  pollicis,  and  palmaris  profunda :  the 
radial  artery  at  first  lies  between  the  pronator  teres  and 
supinator  longus;  afterwards  between  the  supinator  and 


DUBLIN    DISSECTOR.  135 

flexor  carpi  radialis :  it  then  winds  round  the  carpus,  over 
the  external  lateral  ligament,  and  beneath  the  extensor  ten- 
dons of  the  thumb ;  in  the  fore  arm  it  is  only  overlapped 
above  by  the  supinator  longus ;  in  the  rest  of  its  course  it  is 
superficial ;  it  is  accompanied  by  two  veins,  and  by  the  radial 
branch  of  the  musculo-spiral  nerve,  which  lies  to  its  outer 
side.  The  radial  artery  gives  off,  first,  the  recurrent  branch, 
which  ascends  in  front  of  the  external  condyle,  to  supply 
the  muscles  attached  there,  and  to  inosculate  with  the  supe- 
rior prof un  da  ;  second,  in  its  course  down  the  fore  arm,  seve- 
ral muscular  branches:  third,  near  the  wrist,  the  superfi- 
cialis  volee,  which  passes  to  the  small  muscles  of  the  thumb, 
and  communicates  with  the  superficial  palmar  artery ;  fourth 
and  fifth,  branches  to  the  fore  and  back  part  of  the  carpus : 
and  between  the  thumb  and  index  finger  it  divides  into  its 
three  last  branches ;  the  magna  pollicis  subdivides,  and  sup- 
plies the  sides  of  the  thumb ;  the  radialis  indicis,  in  like 
manner,  supplies  the  fore  finger ;  and  the  palmaris  profunda 
passes  beneath  all  the  flexor  tendons  across  the  four  meta- 
carpal  bones,  forms  the  deep  palmar  arch,  and  then  joins  a 
branch  from  the  ulnar  artery.  The  ulnar  artery  is  larger 
than  the  radial :  it  descends  obliquely  inwards,  beneath  the 
superficial  flexors  and  pronators,  and  lies  on  the  flexor  pro- 
fundus  ;  it  passes  over  the  annular  ligament  into  the  palm  of 
the  hand,  and  there  divides  into  a  superficial  and  deep 
branch ;  this  vessel  is  covered  above  by  several  muscles,  in- 
fer iorly  it  is  superficial,  and  lies  between  the  tendon  of  the 
flexor  sublimis  and  flexor  carpi  ulnaris ;  it  is  attended  by 
its  two  veins,  and  in  the  inferior  two-thirds  of  the  fore  arm 
by  the  ulnar  nerve,  which  always  lies  to  its  ulnar  side  ;  near 
the  wrist  this  nerve  is  somewhat  behind  the  artery.  The 
ulnar  artery  sends  off',  first  and  second,  its  recurrent 
branches,  the  anterior,  small,  ascends  in  front  of  the  inter- 
nal condyle,  the  posterior,  large,  passes  behind  that  condyle 
and  joins  the  inferior  profunda ;  third,  the  interosseous  ar- 
tery, which  passing  backwards,  divides  into  its  posterior  and 
anterior  branch  ;  the  posterior  passes  through  the  upper  part 
of  the  interosseous  space,  and  ascends  in  the  substance  of 
the  ancoriseus  [by  its  recurrent  branch,  after  which  it  de- 
scends upon  the  back  of  the  fore  arm,  as  far  as  the  wrist ;] 
the  anterior  interosseous  descends  between  and  beneath  the 
flexor  profundus  and  flexor  pollicis  as  far  as  the  pronator 
quadratus,  where  it  terminates ;  fourth,  muscular  branches ; 
fifth  and  sixth,  branches,  to  the  back  and  front  of  the 
carpus ;  and  in  the  palm  of  the  hand  it  terminates  in  the 
deep  and  superficial  branch  ;  the  former  sinks  between  the 
muscles  of  the  little  finger,  to  join  the  deep  palmar  arch ; 
the  superficial  runs  across  the  flexor  tendons,  forming  the 


136  DUBLIN    DISSECTOR. 

superficial  arch,  from  the  convex  side  of  which,  the  long 
digital  arteries  arise ;  these  supply  the  three  inner  fingers. 
(See  Vascular  System.) 

In  addition  to  the  cutaneous  nerves  already  noticed,  we 
find  the  median,  ulnar  and  musculo-spiral  descending  in  the 
fore  arm ;  the  median  nerve  passes  between  the  heads  of  the 
pronator  teres,  and  descends  beneath  the  flexor  sublimis,  giv- 
ing off  the  anterior  interosseous  nerve,  and  branches  to  the 
muscles  of  the  fore  arm  ;  it  passes  beneath  the  annular  liga- 
ment, appears  superficial  in  the  palm  of  the  hand  near  the 
thumb,  and  sends  off  digital  branches,  which  accompany 
the  digital  arteries  to  all  the  fingers,  except  the  little  and  the 
ulnar  side  of  the  ring  finger.  The  ulnar  ?ierve  winds  round 
behind  the  internal  condyle,  between  the  heads  of  the  flexor 
carpi  ulnaris,  and  descends  along  the  internal  side  of  the 
ulnar  artery  to  the  hand,  where  it  terminates,  by  dividing 
into  a  small  superficial  and  a  large  deep  branch.  The  mus- 
culo-spiral or  radial  nerve  is  seen  beneath  the  supinator  lon- 
gus,  descending  along  the  outer  side  of  the  radial  artery, 
and  supplying  the  adjacent  muscles ;  near  the  elbow  it 
gives  off  the  posterior  interosseous  nerve,  and  a  little  below 
the  middle  of  the  fore-arm  it  passes  beneath  the  tendon  of 
the  supinator,  and  becomes  cutaneous,  being  distributed  to 
the  integuments  of  the  thumb  and  back  of  the  hand.  (See 
Anatomy  of  the  Nervous  System.) 


CHAPTER    VI. 

DISSECTION  OF   THE  ABDOMEN. 
SECTION  I. 

OF  THE  MUSCLES  ON  THE  ANTERIOR  AND  LATERAL  PARTS 
OF  THE  ABDOMEN, 

DIVIDE  the  integuments  from  the  sternum  to  the  pelvis, 
from  the  crest  of  the  ilium  on  each  side  to  the  umbilicus, 
also  from  this  point  upwards  and  outwards  on  each  side 
over  the  cartilages  of  the  ninth  and  tenth  ribs,  as  high  as 
midway  between  the  axilla  and  the  border  of  the  thorax ; 
dissect  off  the  flaps  ;  the  subcutaneous  cellular  membrane 
will  be  found  dense  and  strong,  so  as  to  have  received  the 
name  of  superficial  fascia ;  this  may  be  removed  along 


DUBLIN    DISSECTOR.  137 

with  the  integuments  from  the  superior  and  lateral  parts 
of  the  abdomen,  but  inferiorly  and  anteriorly  it  may  be 
suffered  to  remain  for  further  examination,  a  knowledge 
of  its  structure  and  connexions  being  of  practical  impor- 
tance in  the  disease  of  hernia.  The  superficial  fascia 
is  continued  from  the  surface  of  the  thorax,  over  the  ab- 
dominal muscles;  weak  and  thin  above,  it  increases  in 
density  as  it  descends  ;  from  the  abdomen  it  extends  on 
either  side  over  Poupart's  ligament  to  the  thigh,  which  it 
invests,  and  in  the  centre  over  the  organs  of  generation  : 
in  the  male  a  process  of  it  passes  round  the  spermatic 
cord  on  each  side,  descends  into  the  scrotum,  and  is  con- 
tinuous with  the  fascia  of  the  perineeum,  and  from  the  li- 
nea  alba  a  thick  portion  runs  to  the  dorsum  of  the  penis, 
invests  this  organ,  and  serves  as  a  suspensory  ligament  to 
it.  In  the  female  it  is  loaded  with  fat  in  this  situation,  and 
descends  into  the  labia.  As  this  fascia  passes  over  Pou- 
part's ligament,  it  is  connected  to  it,  through  the  medium 
of  a  thin  transparent  but  strong  membrane,  which  ascends 
from  the  fascia  lata  of  the  thigh,  and  is  soon  lost  on  the 
abdominal  muscles  ;  to  this  the  superficial  fascia  is  attach- 
ed, so  as  to  give  the  latter  the  appearance  of  adhering  to 
Poupart's  ligament,  although  it  really  is  not  so.  This 
structure  is  sometimes  called  Scarpa's  fascia,  as  that  writer 
has  described  it  under  the  name  of  the  "Aponeurosis  of 
the  fascia  lata,"  it  is  very  unequally  developed  in  different 
subjects ;  some  of  the  inguinal  ganglia  separate  this  from 
the  superficial  fascia,  so  also  does  a  femoral  hernia,  in  its 
ascent  on  the  surface  of  the  abdomen.  About  an  inch 
below  this  ligament,  in  the  groin,  the  superficial  adheres 
intimately  to  the  fascia  lata;  in  this  situation  ifee  former 
is  very  thick  and  laminated,  forming  capsules  for  the  in- 
guinal lymphatic  ganglia,  and  is  connected  to  the  fascia 
lata, -by  vessels  and  nerves  which  perforate  the  latter  in 
their  course  to  and  from  these  ganglia,  the  superficial  fas- 
cia and  integuments  ;  the  fascia  lata  here  also  is  very 
weak,  and  rather  cellular^  so  that  the  superficial  and  deep 
fascias  are  continuous  or  identified  in  this  situation ;  soon 
afterwards,  however,  they  become  distinct.  The  super- 
ficial fascia  is  thinner  along  the  sides  than  it  is  on  the 
forepart  of  the  abdomen  :  its  cutaneous  surface  is  cellular, 
and  closely  connected  to  the  integuments,  particularly  in 
the  median  line  ;  its  posterior  surface  is  more  compact  and 
smooth  ;  several  blood-vessels  ramify  between  the  skin  and 
this  membrane  ;  three  set  on  each  side,  viz.  the  external 
circumflex  ilii,  external  epigastric,  and  external  pudic  ar- 
teries ;  these  all  arise  in  the  groin,  from  the  fermoral  ar- 
tery, or  from  some  of  its  branches,  and  ascend  over  Pou- 
12* 


138  DUBLIN    DISSECTOR. 

part's  ligament:  the  first  ramifies  towards  the  anterior 
spinous  process  of  the  ilium;  the  second,  which  is  the 
largest  of  the  three,  ascends  towards  the  umbilicus ;  and,  the 
third  passes  transversely  towards  the  pubis  ;  these  several 
arteries  supply  the  integuments,  and  inosculate  with  the 
deep  seated  vessels  of  the  same  name ;  they  are  each  ac- 
companied by  one  or  two  veins,  which  are  often  found  re- 
markably tortuous.  The  superficial  fascia  supports  and 
connects  the  fleshy  and  tendinous  fasciculi  of  the  abdomi- 
nal muscles ;  it  also  possesses  a  good  deal  of  elasticity, 
which  assists  these  muscles  in  the  contraction  of  the  parie- 
tes  of  the  abdomen,  Remove  the  integuments  and  fascia 
from  the  surface  of  the  abdominal  muscles,  and  continue 
the  dissection  as  far  back  as  within  two  or  three  inches  of 
the  spine.  In  dissecting  the  external  oblique  muscle  at  its 
upper  and  anterior  part,  care  must  be  taken  not  to  raise  its 
aponeurosis,  which  is  so  thin,  as  it  passes  over  the  anterior 
part  of  the  thorax,  that  it  may  be  mistaken  for  condensed 
cellular  membrane.  In  order  to  expose  the  external  obli- 
que muscle,  make  its  fibres  tense  by  putting  a  block  under 
the  loins,  and  dissect  in  a  line  nearly  parallel  to  its  fibres ; 
to  clean  the  posterior  portion,  the  subject  should  be  turned 
a  little  to  the  opposite  side.  The  abdominal  muscles  con- 
sist of  five  pair,  viz.  obliqui  externi,  and  interni,  transver- 
sales,  recti,  and  pyramidales. 

[These  muscles  are  found  in  three  layers,  in  the  first  one  pair,  in 
the  second  three  .pair,  and  in  the  third  one  pair. 

FIRST    LAYER,  OWE    PAIR. 

^Obliquus  Externus,  or  Descendens. 

SECOND   LAYER,    THREE    PAIR. 

Obliquus  Internus,  or  Ascendens. 
Rectus  Abdominis. 
Pyramidalis. 

THIRD    LAYER,    ONE    PAIR. 

Transversalis  Abdominis.] 

OBLIQUUS  EXTERNUS,  or  DESCENDENS,  broad,  thin,  and 
somewhat  square,  extends  over  the  anterior  and  lateral 
parts  of  the  abdomen,  fleshy  above  and  behind,  tendinous 
before  and  below ;  it  arises  by  eight  or  nine  triangular 
fleshy  slips,  sometimes  there  are  only  seven,  from  the  low- 
er edges  and  external  surface  of  the  eight  or  nine  inferior 
ribs,  at  a  little  distance  from  their  cartilages;  the  five  su- 
perior indigitate  with  corresponding  portions  of  the  serra- 
tus  magnus ;  and  the  three  inferior  with  those  of  the  latis- 
simus  dorsi,  by  which  they  are  a  little  overlapped.  The 
superior  fibres  are  thin,  aponeurotic,  and  weak,  and  pass 


1WBLIN    DISSECTOR.  139 

horizontally  inwards;  a  tendinous  and  fleshy  slip  often 
connects  this  portion  to  the  great  pectoral  muscle:  the 
middle  are  the  longest,  and  descend  obliquely  forwards 
and  inwards ;  the  posterior  are  strong  and  fleshy,  and  de- 
scend almost  vertically:  the  superior  and  middle  fibres 
end  in  a  broad  tendon,  which  commences  at  a  little  dis- 
tance external  to  the  linea  semilunaris  ;  this  tendon  is  con- 
tinued over  the  forepart  of  the  abdomen,  covers  the  rectus 
muscle,  and  is  so  broad  inferiorly,  as  when  taken  with  its 
fellow  to  extend  from  one  .spine  of  the  ilium  to  that  of  the 
opposite  side,;  it  is  very  strong  inferiorly,  but  so  very  thin 
above,  where  it  covers  the  thoracic  portion  of  the  rectus, 
that  the  inexperienced  dissector  often  removes  it  along 
with  the  integuments.  The  external  oblique  is  inserted  ten- 
dinous into  the  ensiforni  cartilage,  linea  alba,  pubis,  Pou- 
part's  ligament,  which  is  formed  by  this  tendon,  and  into 
the  anterior  superior  spinous  process  of  the  ilium,  also 
tendinous  and  fleshy  into  the  outer  edge  of  the  two  anterior 
thirds  of  the  orest  of  the  ilium.  Use,  to  depress  the  ribs, 
and  compress  the  abdominal  viscera,  so  as  to  assist  in  ex- 
piration, and  in  the  evacuation  of  the  urine  and  faeces. 
When  both  muscles  act,  they  can  bend  the  trunk  for- 
wards ;  if  one  only  act,  it  will  bend  it  to  that  side,  and  it 
may  also  rotate  it  to  the  opposite  side.  This  muscle  is 
covered  by  the  skin  and  superficial  fascia,  its  posterior 
border  is  sometimes  overlapped  by  the  latissimus  dorsi ; 
in  some  cases,  however,  these  muscles  do  not  meet,  and  a 
small  part  of  the  internal  oblique  is  seen  in  the  triangular 
space  between  them. 

[Variety.  This  muscle  maybe  defective  at  different  points,  thus 
giving  a  tendency  to  the  formation  of  ventral  herniae.J 

On  the  dissected  tendons  of  this  pair  of  muscles,  we  may 
remark  the  following  particulars  ;  the  linea  alba  and  um- 
bilicus, linese  semilwmres,  linese  transversse,  the  external 
abdominal  or  inguinal  rings,  arid  Pouparf s  ligament  on 
each  side.  The  linea  alba  is  a  dense  ligamentous  cord,  ex- 
tending from  the  ensiform  cartilage  to  the  upper  part  of 
the  symphisis  pubis ;  it  is  formed  by  the  intimate  union, 
or  by  the  crossing  of  the  tendinous  fibres  of  the  two  ob- 
lique and  transverse  muscles  of  opposite  sides ;  its  great- 
est breadth  is  at  the  umbilicus,  from  this  to  the  pubis  it  de- 
creases ;  its  superior  portion  is  much  broader  than  its  in- 
ferior :  the  integuments  are  more  closely  connected  to  this 
line,  than  they  are  at  either  side ;  hence  the  more  fat  the 
subject,  the  more  indented  will  the  skin  appear  along  it. 
About  the  centre  of  the  linea  alba  is  the  umbilicus;  this,  in 
the  foetus,  was  a  foramen,  through  which  were  transmitted 


140  DUBLIN    DISSECTOR. 

the  umbilical  vein  from  the  mother,  and  the  umbilical  ar- 
teries and  the  urachus  from  the  child ;  before  the  integu- 
ments were  removed,  this  spot  appeared  depressed,  partic- 
ularly if  the  subject  have  been  very  fat ;  it  now  projects, 
and  seems  formed  of  dense,  cicatrized  cellular  tissue,  sur- 
rounded by,  and  connected  to  the  adjacent  tendinous  fibres. 
Umbilical  hernia  occurs  in  the  infant  through  this  open- 
ing, but  in  the  adult  in  its  immediate  vicinity. 

The  linea  alba  may  be  regarded  as  the  continuation  of 
the  sternum,  it  serves  as  a  fixed  point  for  the  oblique  and 
transverse  muscles  on  either  side,  also  as  a  ligament  to 
connect  the  thorax  to  the  pelvis,  and  to  support  the  former 
when  bending  the  trunk  backwards,  so  as  to  resist  or  pre- 
vent too  forcible  extension  of  the  spine.  In  the  inferior 
part  of  this  line  the  following  operations  may  be  perform- 
ed :  puncturing  the  bladder  in  retention  of  urine :  para- 
centesis,  or  tapping  of  the  abdomen,  in  ascites ;  and  the 
high  operation  for  lithotomy. 

The  inferior  fourth  or  fifth  part  of  the  linea  alba  is 
sometimes  deficient,  as  also  a  portion  of  the  muscles  on 
each  side ;  so  that  the  urinary  bladder  is  superficial,  and 
constantly  exposed :  in  such  cases  the  anterior  part  of 
this  viscus  also  is  usually  wanting,  and  therefore  its  cav- 
ity and  the  orifices  of  the  ureters  can  be  perceived  during 
life. 

The  linea  semilunarls  extends  from  the  tuberosity  of  the 
pubis  on  each  side  upwards  and  outwards,  about  four  in- 
ches from  the  linea  alba,  towards  the  cartilages  of  the 
eighth  and  ninth  ribs ;  it  appears  white,  and  somewhat  de- 
pressed, and  is  formed  by  the  tendon  of  the  internal  ob- 
lique, dividing  at  the  edge  of  the  rectus  into  two  layers,  to 
enclose  this  muscle  in  a  sort  of  sheath.  In  the  living  sub- 
ject this  line  may  be  traced  by  taking  the  point  midway 
between  the  umbilicus  and  the  anterior  superior  spinous 
process  of  the  ilium,  and  from  it  drawing  one  line  towards 
the  tuberosity  or  spine  of  the  pubis,  and  another  towards 
the  cartilage  of  the  ninth  rib.  The  operation  of  tapping 
ovarian  dropsy,  should  always  be  performed  here :  and 
this  situation  is  also  selected  by  some  as  the  best  for  per- 
forming paracentesis  in  case  of  ascites.  In  this  last  men- 
tioned disease,  however,  this  line  is  not  exactly  midway 
between  the  umbilicus  and  spine  of  the  ilium,  but  half  an 
inch  nearer  the  latter. 

The  linea  transrerscc  are  three  or  four  on  each  side,  they 
cross  the  rectus  muscle  from  the  linea  alba  to  the  linea 
semilunaris ;  they  are  tendinous  intersections  of  that  mus- 
cle, particularly  of  its  anterior  part,  which  adhere  so  inti- 
mately to  its  sheath,  as  to  give  to  the  latter  this  indented 


DUBLIN    DISSECTOR.  141 

appearance.  They  are  much  better  marked  in  some  than 
in  others ;  during  life  they  are  very  distinct,  when  the  ab- 
dominal muscles  are  in  strong  action.  These  lines  will  be 
again  noticed  in  the  dissection  of  the  rectus.  Between  the 
linea  alba  and  semilunaris  on  each  side  many  small  holes 
are  often  to  be  observed  in  the  tendon  of  the  external  ob- 
lique :  these  are  only  for  the  transmission  of  small  vessels 
and  nerves :  they  are  generally  of  a  square  form,  and  are 
much  larger  and  more  numerous  in  some  than  in  others. 
External  and  superior  to  the  pubis  on  each  side  we  may 
always  remark  the  opening  called  the  external  inguinal,  or 
abdominal  ring,  transmitting  in  the  rnale  subject  the  sper- 
matic vessels  and  cremaster  muscle,  and  in  the  female  the 
round  ligament  of  the  uterus.  This  opening  is  of  a  trian- 
gular form,  the  base  at  the  pubis,  the  apex  is  superior  and 
external ;  the  sides  are  called  the  pillars  of  the  ring,  one 
of  which  is  superior,  internal,  and  anterior ;  the  other,  or 
Poupart's  ligament,  is  inferior,  external,  and  posterior ;  the 
first,  or  superior  pillar,  is  broad,  and  inserted  into  the  sym- 
physis  and  into  the  opposite  pubis ;  some  fibres  are  con- 
tinuous with  the  fascia  lata  of  the  opposite  thigh ;  this  pil- 
lar decussates  with  that  of  the  opposite  side,  on  the  fore- 
part of  the  pubis,  and  both  send  fibres  to  the  dorsum  of  the 
penis ;  the  inferior  pillar  is  the  internal  or  pubic  portion 
of  Poupart's  ligament ;  the  apex  of  this  opening  is  round- 
ed by  a  series  of  fibres,  which  serve  to  connect  the  pillars 
to  each  other.  These  fibres  arise  from  Poupart's  ligament 
at  a  little  distance  from  the  spine  of  the  ilium,  pass  in 
curved  lines  upwards  and  inwards  across  the  upper  part 
of  the  ring,  and  are  lost  on  the  surface  of  the  tendon  ;  they 
serve,  by  preventing  the  separation  of  the  sides  of  the  ring, 
to  protect  this  part  of  the  abdomen  against  a  protrusion  of 
its  contents.  These  fibres  are  in  some  cases  so  closely 
connected,  as  to  merit  the  name  of  a  fascia  (the  intercolum- 
nal  fascia) ;  this,  in  old  cases  of  hernia,  has  been  found  of 
great  strength,  and  prolonged  for  some  distance  on  the 
hernial  sac,  and  intimately  connected  with  the  cremaster 
muscle  (fascia  spermatica) ;  it  is  this  fascia,  or  these  in- 
tercolumnal  bands,  that  obscure  this  opening  in  many 
cases,  and  deprive  it  of  that  defined  figure  usually  men- 
tioned by  writers,  or  delineated  in  plates.  The  tendon  of 
the  external  oblique  is  alone  concerned  in  the  formation 
of  the  external  abdominal  ring,  there  being  no  correspond- 
ing deficiency  in  the  internal  oblique  or  transverse  mus- 
cles ;  the  spermatic  cord,  or  round  ligament,  must  there- 
fore take  an  oblique  course  to  arrive  at  this  opening ;  this 
will  be  seen  in  the  next  stage  of  the  dissection. 

Pouparfs  or  Fallopius'   ligament^  or  the  crural  arch,  is  the 


142  DUBLIN     DISSECTOR. 

inferior  thickened  edge  of  the  tendon  of  the  external  ob- 
lique ;  it  is  very  strong,  and  when  the  lower  extremity  is 
extended,  and  the  foot  and  toes  everted,  it  appears  very 
tense ;  if  we  consider  it  as  a  distinct  ligament,  it  may  be 
described  as  having  an  attachment  to,  or  as  arising  from 
the  anterior  superior  spinous  process  of  the  ilium,  and 
thence  descending  obliquely  forwards  and  inwards  to  the 
pubis,  into  which  it  is  inserted  by  two  attachments,  one  an- 
teriorly into  the  tuborosity  or  spine ;  the  other  posteriorly  in- 
to the  linea  innominata  of  the  pubis,  or  the  commencement 
of  the  linea  ilio-pectinea :  the  first  or  iliac  end  of  Poupart's 
ligament  is  broad  and  continuous  above  with  the  tendon 
of  the  oblique,  and  below  with  the  fascia  lata ;  the  an- 
terior portion  of  the  pubal  end,  or  the  second  insertion,  is 
distinct  and  round,  and  can  be  felt  through  the  skin  ;  it 
lies  behind  the  cord,  and  is  connected  to  that  portion  of 
the  fascia  lata  which  covers  the  adductor  muscles  ;  the  pos- 
terior pubal  attachment,  or  the  third  insertion,  also  called 
Gimbernaut's  ligament,  is  broad  and  thin,  and  lies  superior, 
posterior  and  external  to  the  former ;  it  may  be  seen  by 
raising  the  cord  out  of  the  external  ring,  and  everting  Pou- 
part's ligament  a  little  ;  it  is  of  a  triangular  form,  the  apex 
is  anterior  towards  the  tuberosity  or  spine  of  the  pubis  ; 
the  base  is  external  and  posterior,  somewhat  crescentic, 
looking  towards  the  femoral  vessels  ;  to  it  some  fibres  from 
the  outer  or  iliac  part  of  the  fascia  lata  are  attached,  so  as 
to  elongate  it  in  this  direction  ;  this  third  insertion  of  Pou- 
part's ligament  forms  the  internal  boundary  of  the  femoral 
ring,  and  is  therefore  concerned  in  the  anatomy  of  femoral 
hernia,  as  will  be  seen  hereafter.  Poupart's  ligament 
owes  much  of  its  strength  to  its  connexion  with  the  fascia 
lata  of  the  thigh,  as  may  be  seen  at  present,  also  to  its  at- 
tachment to  the  fascioe  transversalis  and  iliaca,  which  will 
be  exposed  in  a  future  stage  of  the  dissection.  Poupart's 
ligament  is  of  use  in  strengthening  the  inferior  part  of  the 
abdomen,  and  affording  a  fixed  point  of  attachment  to  the 
deeper  muscles  and  to  the  different  aponeuroses ;  it  also 
protects  the  great  femoral  vessels  and  nerves  in  their  pas- 
sage from  the  abdomen  to  the  thigh,  and  its  third  insertion 
partly  fills  up  the  internal  portion  of  the  crural  arch. 
From  this  third  insertion,  and  from  the  pubis,  a  band  of 
fibres  may  be  observed  to  pass  upwards  and  inwards  be- 
hind the  superior  pillar  of  the  ring  towards  the  linea  alba  ; 
these  assume  in  general,  a  triangular  shape,  and  have 
received  the  name  of  the  triangular  ligament  or  fascia  ;  the 
base  is  inferiorly  at  the  linea  ileo-pectinea  ;  the  apex  is 
superior  and  internal  towards  the  linea  alba,  and  is  conti- 
nuous \vrth  the  external  oblique  tendon  of  the  opposite 


DUBLIN    DISSECTOR.  143 

side  :  this  fascia  serves  to  protect  the  abdomen  in  this  re« 
gion.  Raise  the  external  oblique,  by  dissecting  off  its  ser- 
rated origins  from  the  ribs,  detach  also  its  insertion  from 
the  crest  of  the  ilium,  and  from  the  internal  oblique  mus- 
cle, cleaning,  at  the  same  time,  the  surface  of  the  latter, 
throw  the  external  oblique  towards  the  opposite  side,  sepa- 
rating it  as  far  forwards  as  its  connexions  will  permit,  that 
is,  about  half  an  inch  internal  to  the  linea  semilunaris; 
divide  its  tendon  transversely  from  the  spine  of  the  ilium, 
towards  the  lower  third  of  the  rectus,  about  an  inch  above 
the  external  ring,  thus  preserving  Poupart's  ligament  arid 
the  external  ring  for  further  examination,  in  relation  to 
the  anatomy  of  hernia.  When  the  external  oblique  is 
raised,  we  see  the  inferior  ribs,  the  inferior  intercostal 
muscles,  the  internal  oblique,  and  the  cremaster. 

OBLIQUUS  INTERNUS,  or  ASCENDENS,  is  also  situated  at  the 
anterior  and  lateral  part  of  the  abdomen,  broader  before 
than  behind,  and  more  fleshy  below  than  above ;  it  arises 
tendinous,  but  soon  becomes  fleshy,  from  the  fascia  lumbo- 
rum,  from  all  the  crest  of  the  ilium,  and  from  the  two  ex- 
ternal thirds  of  the  grooved  or  abdominal  surface  of  Pou- 
part's ligament,  the  fibres  diverge  in  a  radiated  manner ; 
those  from  the  lumbar  fascia  and  posterior  part  of  the 
ilium  ascend  obliquely  forwards ;  those  from  the  anterior 
part  of  the  ilium  pass  transversely,  and  those  from  Pou- 
part's ligament  descend  obliquely  inwards  ;  the  fibres  con- 
tinue fleshy  further  forward  than  those  of  the  external  ob- 
lique ;  at  the  linea  semilunaris  they  end  in  a  flat  tendon, 
which,  at  the  edge  of  the  rectus,  divides  into  two  layers,  to 
enclose  this  muscle  ;  the  anterior  is  united  to  the  tendon 
of  the  external  oblique,  the  posterior  and  thinner  layer  is 
joined  to  the  tendon  of  the  transversalis  ;  about  midway 
between  the  umbilicus  and  the  pubis,  the  tendon  of  the  in- 
ternal oblique  does  not  divide,  but  the  whole  passes  in 
front  of  the  rectus,  along  with  the  tendon  of  the  transversa- 
lis, to  which  it  is  closely  connected;  a  little  above  the  pu- 
bis these  two  tendons  are  inseparably  joined,  and  are  call- 
ed the  conjoined  tendons.  The  internal  oblique  is  inserted, 
tendinous  and  fleshy,  into  the  cartilages  of  the  six  inferior 
ribs,  tendinous  into  the  ensiform  cartilage,  and  into  the 
whole  length  of  the  linea  alba  ;  the  conjoined  tendons  are 
inserted  into  the  symphisis  and  upper  edge  of  the  pubis, 
and  passing  external  to  the  rectus  are  also  inserted  into 
the  linea  innominata,  where  they  are  connected  with  Gim- 
bernaut's  ligament,  and  inseparably  joined  to  the  fascia 
transversalis  ;  these  conjoined  tendons  lie  posterior  to  the 
spermatic  cord  and  to  the  triangular  ligament,  and  afford 
much  security  to  that  part  of  the  abdomen  behind  the  ex- 


144  DUBLIN    DISSECTOR. 

ternal  abdominal  ring.  Use  of  the  internal  oblique  mus- 
cle, to  assist  the  external  oblique  in  expiration,  and  in  com- 
pressing the  abdominal  viscera,  also  in  bending  the  trunk 
forwards,  or  to  one  side  ;  it  can  also  rotate  the  trunk,  but 
in  doing  so,  it  co-operates  with  the  external  oblique  of  the 
opposite  side,  with  which  it  forms  a  sort  of  digastric  mus- 
cle ;  this  muscle  is  covered  by  the  external  oblique  and 
latissimus  dorsi;  it  lies  on  the  transversalis  muscle  ;  some 
small  vessels  ramify  between  them  :  a,  small  portion  of  the 
internal  oblique  is  sometimes  superficial,  between  the  ex- 
ternal oblique  and  latissimus  dorsi,  and  above  the  posterior 
part  of  the  ilium. 

[Variety.     This  muscle  also,  is  sometimes  deficient  at  some  parts.] 

Along  the  inferior  border  of  this  muscle  we  observe  the 
following : 

CREMASTER,  consists  of  a  fasciculus  of  pale  fleshy  fibres, 
which  arise  from  the  internal  surface  of  the  external  third 
of  Poupart's  ligament,  and  from  the  lower  edge  of  the  last 
described  muscle ;  a  few  fibres  also  sometimes  proceed 
from  the  lower  edge  of  the  transversalis  muscle ;  it  fre- 
quently too  has  a  tendinous  attachment  to  the  pubis,  be- 
hind the  external  abdominal  ring ;  the  fibres  all  pass  down- 
wards and  forwards  around  the  spermatic  cord,  but  chiefly 
along  its  outer  side,  many  of  them  in  the  form  of  arches 
reversed  or  concave  upwards ;  they  are  inserted  into  the 
tunica  vaginalis  ;  a  few  fibres  are  lost  in  the  scrotum.  Use, 
to  support,  compress,  and  raise  the  testicle  and  its  vessels  ; 
the  origin  of  this  muscle  is  covered  by  the  tendon  of  the 
external  oblique,  and  lies  on  the  fascia  transversalis ;  a 
small  but  long  nerve,  a  branch  from  one  of  the  lumbar 
nerves,  runs  between  its  fibres  ;  the  lower  part  of  the  mus- 
cle is  superficial  and  very  pale ;  in  cases  of  old  hernia, 
the  fibres  of  the  cremaster  are  found  greatly  increased  in 
thickness  and  are  often  of  a  yellow  colour ;  and  in  that 
form  of  the  disease  called  the  oblique,  or  common  inguinal 
hernia  this  muscle  always  forms  one  of  the  coverings  of 
the  sac.  The  cremaster  is  absent  in  the  female.  This 
muscle  is  probably  formed  incidentally,  the  testis,  in  its 
descent  to  the  scrotum,  carrying  before  it  the  lower  bor- 
der of  the  internal  oblique  ;  hence  too  the  arched  direction 
of  some  of  its  fasciculi.  Raise  off  the  internal  oblique 
from  the  transversalis  muscle  ;  commence  above  the  ante- 
rior part  of  the  crest  of  the  ilium,  where  the  muscles  are 
separated  by  cellular  membrane,  and  some  branches  of 
the  circumflex-ilii  vessels,  make  one  incision  from  the  ilium 
towards  the  cartilage  of  the  ninth  rib,  and  another  from 
the  ilium,  towards  the  lower  third  of  the  linea  semilunaris ; 


DUBLIN    DISSECTOR.  145 

carefully  dissect  off  the  posterior  part  of  the  muscle,  to- 
wards the  spine,  and  the  anterior  towards  the  rectus  ;  this 
portion  can  be  separated  from  the  transversalis,  a  little  be- 
yond the  linea  semilunaris. 

TRANSVERSALIS,  somewhat  square,  broader  anteriorly 
than  posteriorly,  arises  tendinous  from  the  fascia  lumbo- 
rum  and  the  posterior  part  of  the  crest  of  the  ilium,  fleshy 
from  the  remaining  anterior  part  of  the  crest,  and  from  the 
iliac  third  of  Poupart's  ligament ;  it  also  arises  tendinous 
from  the  two  last  ribs,  and  by  fleshy  slips  from  the  inner 
side  of  the  five  succeeding ;  these  indigitate  with  the  ori- 
gins of  the  diaphragm  ;  all  the  fibres  pass  transversely 
forwards,  except  the  most  inferior,  which  are  curved  a  lit- 
tle downwards  ;  they  all  end  in  a  flat  tendon,  which,  near 
the  linea  semilunaris,  joins  the  posterior  lamina  of  the  in- 
ternal oblique,  and  is  inserted  along  with  it  into  the  whole 
length  of  the  linea  alba,  into  the  upper  edge  of  the  pubis, 
and  into  the  linea  innominata ;  this  tendon  passes  behind 
the  rectus  superiorly  ;  but  inferiorly,  that  is,  about  mid- 
way between  the  umbilicus  and  the  pubis,  the  conjoined 
tendons  pass  anterior  to  this  muscle,  and  are  inserted  in  the 
manner  before  mentioned.  The  transversalis  abdominis 
is  covered  by  the  internal  and  external  oblique ;  it  lies  on 
the  fascia  transversalis  and  on  the  peritonaeum.  Use,  to 
compress  the  abdominal  viscera,  and  assist  in  expiration ; 
this  muscle  is  tendinous  before  and  behind,  fleshy  in  the 
middle,  also  above  and  below,  contrary  to  the  two  oblique 
muscles ;  the  posterior  tendon  is  described  by  some,  not 
improperly,  as  dividing  into  three  layers,  which  are  in  fact 
the  three  sheets  or  leaves  of  the  lumbar  fascia ;  the  poste- 
rior, very  strong,  is  continuous  with  the  fascia  lumborum  ; 
the  middle,  thinner  and  weaker,  is  attached  to  the  trans- 
verse processes  of  the  lumbar  vertebrae  ;  and  is  separated 
from  the  former  by  the  lumbar  muscles ;  and  the  anterior 
lamina,  which  is  the  weakest,  is  expanded  over  the  qua- 
dratus  lumborum,  and  the  inferior  part  of  the  diaphragm, 
and  is  connected  to  the  sides  of  the  bodies  of  the  lumbar 
vertebrae.  The  inferior  edge  of  the  transversalis  is  in  some 
degree  confounded  with  that  of  the  internal  oblique  ;  parti- 
cularly at  their  origin  from  Poupart's  ligament ;  it  seldom, 
however,  descends  as  low  as  that  muscle,  and  it  crosses 
the  spermatic  cord,  or  round  ligament,  just  as  either  of 
these  is  about  to  enter  the  abdomen :  the  conjoined  ten- 
dons also  often  admit  of  separation  inferiorly  near  the  ex- 
ternal ring,  when  the  tendon  of  the  transversalis  muscle 
may  be  traced  very  distinctly  behind  the  cord,  intimately 
united  to  the  transversalis  fascia.  Replace  the  oblique 
muscles,  divide  their  tendons  all  along  the  side  of  the  linea 

13 


146  DUBLIN    DISSECTOR. 

alba,  and  dissect  them  off  the  rectus  towards  the  linea  se- 
milunaris;  this  anterior  part  of  the  sheath  adheres  so 
closely  to  the  linese  transversse,  that  it  is  difficult  to  sepa- 
rate it  from  them. 

RECTUS,  long  and  flat,  broader  above  than  below,  arises 
by  a  flat  tendon,  which  is  sometimes  double,  from  the  up- 
per and  anterior  part  of  the  pubis,  ascends  parallel  to  its 
fellow,  becomes  broad  and  thin  above  the  umbilicus,  and 
is  inserted  into  the  anterior  part  of  the  thorax  by  three 
fasciculi,  the  internal  one  of  which  is  fixed  to  the  ensiform 
cartilage  and  costo-xiphoid  ligament ;  the  middle,  longer, 
and  thinner,  to  the  cartilage  of  the  sixth  rib ;  and  the  ex- 
ternal, still  broader  and  thinner,  to  the  cartilage  of  the 
fifth  rib.  Use,  to  bend  the  chest  towards  the  pelvis,  or  to 
raise  the  latter  towards  the  chest,  also  to  compress  the  ab- 
domen. The  rectus  is  covered  superiorly  by  the  great 
pectoral,  in  the  middle  by  the  tendon  of  the  external,  and 
the  anterior  layer  of  that  of  the  internal  oblique  muscle, 
and  inferiorly  by  the  external  oblique  and  the  conjoined  ten- 
dons of  the  internal  oblique  and  transVersalis,  also  by  the 
pyramidalis.  These  muscles  are  much  nearer  to  each 
other  below  than  above ;  they  are  each  enclosed  in  a  dis- 
tinct sheath,  which  consists,  anteriorly,  of  the  tendon  of 
the  external  oblique  and  the  anterior  lamina  of  the  inter- 
nal oblique,  posteriorly  of  the  posterior  layer  of  the  inter- 
nal oblique,  and  the  tendon  of  the  trans versalis.  This 
sheath  commences  at  the  edge  of  the  thorax,  and  terminates 
midway  between  the  umbilicus  and  the  pubis ;  below 
which,  all  the  tendons  pass  anterior  to  this  muscle.  If  this 
part  of  the  rectus  be  divided,  the  deficiency  in  the  back  of 
the  sheath  will  be  obvious,  as  it  generally  terminates  ab- 
ruptly by  a  lunated  edge ;  in  some  cases,  however,  it  ends 
gradually :  the  epigastric  vessels  ascend  within  this  sheath, 
on  the  posterior  surface  of  the  muscle.  The  sheath  of  the 
rectus  serves  to  confine  this  muscle  in  its  proper  place,  and 
t'o  prevent  it,  when  contracted,  from  injuring  the  abdomi- 
nal viscera  immediately  behind  it ;  it  also  strengthens  the 
parietes  of  the  abdomen,  and  prevents  the  more  frequent 
occurrence  of  hernia ;  the  deficiency  in  the  back  part  of 
the  sheath  below,  may  permit  the  abdominal  muscles  to 
exert  more  direct  influence  on  the  urinary  bladder  when 
distended.  The  rectus  is  intersected  by  three  or  four  irregu- 
lar, or  zigzag,  transverse,  tendinous  lines  ;  one  of  these  is 
always  to  be  found  opposite  the  umbilicus,  a  second  mid- 
way between  this  and  the  xiphoid  cartilage,  opposite  to 
which  a  third  is  always  placed  ;  if  a  fourth  exist,  it  will  be 
found  below  the  umbilicus  :  these  intersections  are  not  com- 
plete ;  they  are  generally  deficient  on  the  back  part  of  the 


DUBLIN    DISISSECTOR.  147 

muscle  ;  the  anterior  part  of  the  sheath  adheres  intimately 
to  each  of  them,  some  fleshy  fibres  pass  over  one  line  and 
are  inserted  into  those  above  and  below,  hence  the  .poste- 
rior fasciculi  are  longer  than  the  anterior;  by  means 
of  these  lines  the  rectus  is  a  sort  of  polygastric  muscle, 
and  is  enabled  to  act  in  distinct  or  separate  portions,  so 
as  to  compress  different  parts  of  the  abdomen  in  succes- 
sion, each  section  having  a  distinct  nerve. 

[Varieties.  This  muscle  is  attached  to  the  eighth  rib,  when  that 
bone  reaches  the  sternum,  as  is  sometimes  the  case ;  it  also  some, 
times  ascends  as  high  as  the  fourth  rib,  in  other  cases  as  high  as  the 
neck,  in  front  of  the  pectoralis  major.] 

Anterior  to  the  origin  of  the  rectus  is  the  following  small 
muscle : 

PYRAMIDALIS,  is  sometimes  absent,  it  arises  broad  and 
fleshy  from  the  pubis,  ascends  obliquely  inwards,  and  is 
inserted  narrow  and  tendinous  into  the  linea  alba,  midway 
between  the  umbilicus  and  pubis.  Use,  it  assists  the  rec- 
tus, and  makes  tense  the  linea  alba ;  it  is  covered  by  the 
tendon  of  the  external  oblique,  by  the  triangular  liga- 
ment and  the  conjoined  tendons :  it  appears  in  some 
cases  to  be  enclosed  in  a  splitting  of  the  latter. 

[Varieties.  This  muscle  is  often  wanting,  sometimes  there  are 
two,  three,  and  even  four  on  a  side.] 

Dissect  off  the  transversalis  muscle  in  a  direction  from 
the  ilium  towards  the  linea  semilunaris,  and  the  fascia 
transversalis  will  be  exposed  covering  the  peritonaeum ;  this 
fascia  is  connected  to  the  internal  lip  of  the  ilium  and  to 
the  whole  length  of  Pou part's  ligament,  as  far  as  the  third 
insertion  or  Gimbernaut's  ligament,  from  which  it  is  con- 
tinued behind  the  rectus  to  that  of  the  opposite  side ;  from 
these  attachments,  the  fascia  transversalis  ascends  between 
the  peritonaeum  and  the  transversalis  muscle,  as  high  as 
the  diaphragm,  and  as  far  back  as  the  psoas  magnus ;  it 
is  very  strong  and  tense  inferiorly  for  about  an  inch  above 
Poupart's  ligament,  but  superiorly  it  is  little  more  than 
condensed  cellular  membrane :  this  fascia  serves  to  sup- 
port the  peritonaeum,  particularly  at  the  inferior  part  of 
the  abdomen,  where  the  internal  oblique  and  transversalis 
muscles  are  deficient ;  the  spermatic  cord  or  the  round 
ligament  always  perforates  this  fascia  about  three  quarters 
of  an  inch  above  Poupart's  ligament,  and  about  an  inch 
and  a  half  from  the  tuberosity  of  the  pubis ;  this  perfora- 
tion is  called  the  internal  abdominal  ring,  and  is  situated 
about  midway  between  the  spine  of  the  ilium  and  the 
symphisis  pubis;  it  is  not  a  distinct  opening,  for  the  edges 
are  prolonged  along  the  cord,  and  lost  in  its  cellular  cover- 


148  DUBLIN    DISSECTOR. 

ing.  The  interval  between  the  internal  and  external  ab- 
dominal rings  is  traversed  by  the  spermatic  cord,  and  is 
named  the  inguinal  or  spermatic  canal,  to  the  anatomy  of 
which  the  student  should  particularly  attend,  as  the  disease 
of  inguinal  hernia  is  situated  here,  in  the  treatment  of  which 
a  correct  knowledge  of  this  region  will  be  required.  The 
spermatic  or  inguinal  canal  commences  at  the  internal  ring, 
and  leads  obliquely  downwards,  forwards,  and  inwards  to 
the  external  ring,  where  it  terminates ;  this  passage  is 
bounded  anteriorly  by  the  skin  and  fascice,  the  tendon  of 
the  external  oblique,  and  by  the  inferior  fleshy  margin  of 
the  internal  oblique  and  transverse  muscles,  posteriorly 
by  the  transversalis  fascia  and  by  the  conjoined  tendons 
of  the  two  last  named  muscles,  inferiorly  by  Pou part's  li- 
gament and  its  third  insertion,  superiorly  this  space  is 
closed  by  the  apposition  of  its  opposite  sides ;  in  the  male 
the  spermatic  cord  and  cremaster  muscle,  and  in  the  female 
the  round  ligament  of  the  womb  passes  through  this  canal, 
the  obliquity  or  valve-like  structure  of  which  serves  to 
protect  the  abdomen  against  a  protrusion  of  its  contents. 
Inguinal  hernia  occurs  more  frequently  in  the  male  than 
in  the  female  sex,  in  consequence  of  the  spermatic  cord 
and  the  inguinal  rings  in  man  being  larger  than  the  liga- 
mentum  teres  or  these  openings  in  the  female  :  there  are 
two  species  of  this  disease,  oblique  and  direct.  Oblique 
inguinal  hernia  is  the  more  common  form  ;  in  this  case,  the 
peritonaeum  or  hernial  sac,  with  its  contents,  protrude 
through  the  internal  ring  along  the  anterior  part  of  the 
spermatic  vessels,  carrying  before  it  the  surrounding  cel- 
lular tissue  and  a  prolongation  of  the  fascia  transversalis 
from  the  edges  of  the  opening ;  this  covering  of  the  her- 
nial sac  is  called  the  fascia  propria  of  inguinal  hernia,  and 
by  some  the  fascia  infundibuliforme.  When  the  tumour 
has  arrived  at  the  lower  edge  of  the  transversalis  and  inter- 
nal oblique  it  insinuates  itself  between  the  cremaster  mus- 
cle and  the  vessels  of  the  cord,  along  which  it  descends  to 
the  external  ring,  where  it  is  in  general  delayed  for  some 
time ;  the  form  of  this  opening  and  the  inter-columnar  fas- 
cia preventing  its  free  passage  through  it;  as  the  sac, 
however,  descends  towards  the  scrotum  these  inter-colum- 
nar fibres  become  closely  united  to  the  cremaster,  and  are 
gradually  elongated  on  the  surface  of  the  tumour. 

If  the  sac  of  an  oblique  inguinal  hernia  which  has  passed 
the  external  ring  be  carefully  dissected,  it  will  be  found 
covered  by  the  following  parts ;  beneath  the  integuments 
the  superficial  fascia,  in  general  much  thickened  and  divisi- 
ble into  several  laminae,  will  be  seen  to  surround  the  tumour ; 
on  dissecting  off  this,  the  fibres  of  the  cremaster,  in  general 


DUBLIN    DISSECTOR.  ]  49 

also  thickened,  will  be  observed  spread  on  the  forepart  and 
sides  of  the  sac,  the  inter-columnar  bands  from  the  external 
oblique  tendon  will  be  found  closely  connected  to  this  mus- 
cle, and  both  will  form  a  sort  of  capsule  for  the  sac,  sus- 
pending it  towards  the  abdomen ;  if  this  covering  be  divided, 
the  fascia  propria  will  appear  closely  investing  the  tumour, 
and  so  adhering  to  it  as  to  be  separated  with  difficulty  from 
it ;  this  covering  can  often  be  divided  into  several  layers,  it 
presents,  however,  great  difference  in  different  cases;  be- 
neath this,  the  hernial  sac  or  the  peritoneum  will  be  found, 
which  also  in  cases  of  old  hernia  will  be  considerably  thick- 
ened ;  on  opening  the  hernial  sac,  its  contents,  either  omen- 
turn  or  intestine,  will  be  seen.  The  student  should  next  at- 
tend to  the  situation  of  the  epigastric  vessels  and  their  rela- 
tion to  the  parts  concerned  in  oblique  inguinal  hernia ;  these 
vessels  are  placed  behind  the  fascia  transversalis  between  it 
and  the  peritoneum,  and  in  general  can  be  discerned  through 
the  fascia ;  if  not,  a  little  dissection  will  render  them  appa- 
rent ;  two  veins  usually  accompany  the  artery,  one  on  either 
side ;  sometimes  there  is  but  one  epigastric  vein,  and  that  is 
on  the  pubal  or  inner  side  of  the  artery  ;  the  epigastric  artery 
arises  from  the  external  iliac  near  Poupart's  ligament ;  it 
first  descends  a  little  forwards  and  inwards,  then  ascends 
toward  the  rectus  muscle,  immediately  behind  the  fascia 
transversalis,  and  very  near  to  the  inner  or  pubal  side  of  the 
internal  abdominal  ring ;  in  oblique  inguinal  hernia  the  neck 
of  the  sac  is  nearly  in  contact  with  the  epigastric  vessels, 
which  thus  bound  it  on  its  internal  side,  hence  the  rule  of 
practice,  in  performing  the  operation  for  the  relief  of  stran- 
gulated oblique  inguinal  hernia,  when  the  stricture  is  seated 
in  the  neck  of  the  sac,  is,  to  direct  the  edge  of  the  knife  or 
bistoury  upwards  and  outwards.  Direct  or  ventro-inguinal 
hernia  protrudes  directly  through  the  external  ring  without 
descending  along  the  spermatic  channel :  the  occurrence  of 
this  disease  is  in  a  great  degree  guarded  against  by  the  fascia 
transversalis,  and  by  the  conjoined  tendons  which  lie  imme- 
diately behind  the  external  ring :  the  edge  of  the  rectus>  the 
triangular  ligament,  and  the  spermatic  cord  may  be  also  all 
enumerated  as  additional  protections  to  this  part  of  the  abdo- 
men :  in  this  species  of  hernia  the  sac  will  be  found  covered 
only  by  the  integuments,  superficial  fascia,  and  some  ten- 
dinous and  aponeurotic  bands  it  may  have  carried  before  it ; 
it  is  not  covered  by  the  cremaster,  and  in  general  it  descends 
along  the  inner  and  anterior  side  of  the  cord,  that  is,  the 
cord  will  be  found  external  and  inferior  or  posterior  to  it, 
but  in  some  few  cases  the  cord  has  been  found  passing 
across  the  neck  of  the  sac,  that  is,  anterior  to  it ;  the  sac  is 
never,  however,  found  between  the  cremaster  muscle  and 
13* 


150  DUBLIN    DISSECTOR. 

the  spermatic  vessels.  The  epigastric  vessels  lie  to  the  iliac 
or  outer  side  of  the  neck  of  the  sac ;  in  dividing  the  latter, 
therefore,  in  case  this  operation  be  required  during  life,  the 
edge  of  the  knife  should  be  directed  upwards  and  inwards. 
When  the  disease  of  oblique  inguinal  hernia  has  continued 
for  a  considerable  length  of  time,  the  spermatic  canal  will 
be  found  altered  in  many  respects  from  its  natural  condi- 
tion; it  will  have  become  dilated  and  shortened,  and  the 
abdominal  rings  expanded  and  approximated  so  as  to  render 
it  difficult  to  distinguish  the  oblique  from  the  direct  inguinal 
hernia.  This  is  the  condition  of  the  inguinal  canal  in  the 
infant ;  on  account  of  the  narrow  pelvis,  the  canal  is  then 
short,  the  rings  are  more  nearly  opposed,  and  of  course,  if 
the  same  exciting  causes  were  present,  hernia  would  be  more 
frequent  in  its  occurrence. 

In  connexion  with  inguinal  hernia,  the  student  may  next 
study  the  anatomy  of  the  groin  in  reference  to  crural  hernia, 
or  he  may  postpone  this  dissection  until  the  contents  of  the 
abdomen  have  been  examined  and  removed ;  we  shall,  how- 
ever, here  subjoin  the  description  of  the  parts  concerned  in 
this  disease :  remove  the  integuments  from  the  anterior  part 
of  the  upper  third  of  the  thigh,  the  superficial  fascia  will  be 
seen  descending  over  Poupart's  ligament  to  invest  the  lower 
extremity ;  in  the  groin  this  fascia  is  very  thick,  and  may 
be  divided  into  several  layers,  which  are  separated  by  lym- 
phatic ganglia  and  the  superficial  inguinal  vessels;  this 
fascia  may  be  easily  raised  from  the  fascia  lata  on  the  outer 
and  inner  sides  of  the  thigh,  but  in  the  middle  of  the  groin 
and  about  an  inch  below  Poupart's  ligament,  these  fasciae 
are  almost  inseparably  joined ;  when  the  superficial  fascia 
shall  have  been  dissected  off  the  forepart  of  the  thigh,  we 
shall  see  several  lymphatic  ganglia,  the  saphena  vein  and 
some  small  blood  vessels  lying  on  the  fascia. 

The  form  and  boundaries  of  the  inguinal  region  also 
may  then  be  more  distinctly  seen ;  the  term  crural  is  some- 
times applied  to  this  space,  and  that  of  inguinal  to  the  smaller 
region  above  Poupart's  ligament ;  I  prefer  naming  the  latter 
spermatic,  and  the  former  inguinal  or  superior  crural.  The 
inguinal  region  is  triangular,  the  base  is  Poupart's  ligament ; 
the  apex  is,  inferiorly,  formed  by  the  meeting  of  the  sartorius 
and  adductor  muscles,  at  the  lower  part  of  the  upper  third 
of  the  thigh ;  the  external  side  is  very  prominent,  and  con- 
sists of  the  sartorius,  iliacus,  rectus  and  other  muscles,  all 
covered  by  the  fascia  lata ;  the  internal  or  pubic  side  is  flat 
and  on  a  plane  posterior  to  the  iliac ;  it  is  formed  by  the 
pectinseus  and  adductor  muscles,  also  covered  by  the  fascia 
lata.  The  inguinal  lymphatic  ganglia  are  irregular  in  num- 


DUBLIN     DISSECTOR.  15 

ber,  and  size,  they  are  in  general  about  twelve  in  number, 
and  may  be  divided  into  a  superficial  and  a  deep  set ;  the 
former  are  the  more  numerous,  and  may  be  arranged  from 
their  situation  into  the  superior  and  inferior ;  the  superior 
are  small,  four  or  five  in  number,  lie  parallel  to  Poupart's 
ligament,  some  above,  others  below  it ;  the  inferior  are 
two  or  three  in  number,  larger  than  the  former,  and  placed 
perpendicularly  or  parallel  to  the  saphena  vein ;  in  general 
one  lies  behind  this  vessel ;  the  deep  inguinal  ganglia  are  be- 
neath the  fascia  lata,  are  three  or  four  in  number,  and  are 
closely  connected  to  the  sheath  of  the  femoral  vessels,  chiefly 
to  its  inner  side ;  in  general  one  occupies  the  femoral  ring. 
The  saphena  vein  is  the  principal  cutaneous  vein  of  the  lower 
extremity ;  it  will  be  seen  in  a  future  dissection  to  arise  from 
the  dorsum  and  inner  side  of  the  foot,  and  to  ascend  in  front 
of  the  inner  ankle  along  the  inner  side  of  the  leg,  and  pass- 
ing behind  the  inner  condyle  of  the  femur  it  continues  to 
ascend  along  the  inner  and  anterior  part  of  the  thigh  to 
within  about  an  inch  and  a  half  or  two  inches  of  Poupart's 
ligament,  when  it  begins  to  pass  through  an  opening  in  the 
fascia  lata,  (the  saphenic  opening,)  it  then  joins  the  femoral 
vein  about  an  inch  or  an  inch  and  a  half  below  the  crural 
arch.  The  saphenic  opening  in  the  fascia  lata  will  be  very 
distinctly  seen  if  the  vein  be  divided  on  the  thigh  and  raised 
towards  Poupart's  ligament,  it  presents  a  well-marked  semi- 
lunar  edge,  the  concavity  looking  upwards ;  the  edge,  though 
apparently  sharp,  yet  if  carefully  examined  will  be  found 
reflected  backwards  on  the  shea'th  of  the  femoral  vessels ; 
remove  the  inguinal  ganglia,  clean  the  surface  of  the  fascia 
lata,  to  the  connexions  of  which  in  this  region  the  student 
should  next  attend.  The  fascia  lata  may  be  observed  to  be 
united  to  the  spine  of  the  ilium,  to  the  whole  length  of  Pou- 
part's ligament,  also  to  the  linea  innominata  and  spine  of 
the  pubis ;  it  covers  the  muscles  on  either  side  of  the  groin, 
and  the  vessels  in  the  middle ;  for  the  purpose  of  more  par- 
ticular examination,  this  fascia  may  be  divided  into  three 
portions,  the  internal  or  pubic  or  pectineal  portion,  the  ex- 
ternal or  iliac,  and  the  middle  or  cribriform  ;  the  internal  or 
pubic  portion  covers  the  pectinseus,  gracilis,  and  adductor 
muscles,  and  is  inserted  internally  into  the  ramus  of  the 
ischium  and  pubis ;  superiorly  into  the  linea  innominata  or 
ilio-pectinea,  anterior  to  Gimbernaut's  ligament ;  externally 
it  passes  behind  the  sheath  of  the  femoral  vessels,  and  at  the 
edge  of  the  psoas  tendon  divides  into  two  lamince,  one  passes 
beneath  that  tendon,  and  is  attached  to  the  capsular  ligament 
of  the  hip-joint ;  the  other  passes  over  that  tendon  and  is 
continued  into  the  deep  surface  of  the  fascia  iliaca.  The 
middle  portion  of  the  fascia  lata  is  very  thin,  and  has  been 


152  DUBLIN    DISSECTOR. 

termed  the  cribriform  fascia ;  this  extends  from  the  saphena 
vein  to  Poupart's  ligament,  and  is  connected  on  either  side 
to  the  pubic  and  iliac  portions  of  the  fascia  lata.  The  cri- 
briform fascia  covers  the  femoral  vessels,  and  is  perforated 
by  the  lymphatic  vessels  passing  to  the  iliac  ganglia  ;  this 
portion  of  the  fascia  lata  is  more  closely  connected  than  any 
other  to  the  superficial  fascia :  indeed  in  structure  it  resem- 
bles the  superficial  more  than  the  fascia  lata,  nor  are  its 
fibres  directly  continued  from  those  of  the  fascia  lata  ;  some 
have,  therefore,  considered  the  cribriform  fascia  as  a  deep 
lamina  of  the  superficial  fascia ;  in  many  cases,  however, 
it  has  an  aponeurotic  structure,  and  appears  to  be  clearly 
derived  from  the  iliac  portion,  and  inserted  into  the  pubic 
portion  of  the  fascia  lata ;  it  presents  much  variety  in  this 
respect.  The  external  or  iliac  portion  of  the  fascia  lata  is 
very  dense  and  strong,  it  is  continued  from  the  external  sur- 
face of  the  thigh,  and  is  intimately  attached  superiorly  to 
the  spine  of  the  ilium,  and  to  Poupart's  ligament ;  and 
uniting  with  the  cribriform  fascia,  is  continued  in  front  of 
the  femoral  vessels,  along  with  the  inferior  fibres  of  Pou- 
part's ligament,  and  is  inserted  along  with  these  into  the 
linea  innominata,  thus  assisting  to  form  the  external  part  or 
the  base  of  Gimbernaut's  ligament.  If  the  cribriform  fascia 
be  removed  along  with  the  superficial  fascia,  then  the  iliac 
portion  of  the  fascia  lata  will  present  the  appearance  of  a 
crescentic  or  falciform  process,  extending  across  the  femoral 
vessels,  the  concavity  of  which  process  will  look  downwards 
and  inwards :  the  inferior  cornu  joins  the  external  cornu  of 
the  saphenic  opening,  and  the  superior  cornu  is  inserted 
along  with  the  posterior  fibres  of  Poupart's  ligament,  or 
Gimbernaut's  ligament,  into  the  linea  innominata,  on  the 
internal  border  of  the  crural  ring ;  although  this  crescentic 
process  appears  to  present  a  defined  edge,  yet  if  the  latter 
be  examined  closely  it  will  be  found  reflected  backwards 
on  the  sheath  of  the  vessels  and  on  the  muscles,  in  the  same 
manner  as  the  apparent  edge  at  the  lower  part  of  the  saphe- 
nic opening. 

Next  direct  your  attention  to  the  internal  surface  of  the 
crural  arch,  and  to  the  connexion  between  it  and  the  deep 
fasciaB  of  the  abdomen,  viz.  the  transversalis  and  iliaca  ; 
divide  the  fascia  transversalis  from  the  spine  of  the  ilium 
towards  the  rectus  muscle ;  dissect  it  carefully  down  from 
the  peritonaeum,  then  push  up  this  membrane,  together 
with  the  caecum  or  sigmoid  flexure  of  the  colon,  out  of  the 
iliac  fossa,  to  which  they  are  connected  by  very  loose  cel- 
lular membrane  ;  we  thus  obtain  a  view  of  the  internal 
surface  of  Poupart's  ligament,  and  of  the  parts  which  pass 
beneath  it,  and  which  naturally  fill  the  space  or  cavity  of 


DUBLIN     DISSECTOR.  153 

the  crural  arch :  first,  observe  the  fascia  transversalis  at- 
tached to  the  inner  lip  of  the  ilium  and  to  Poupart's  liga- 
ment from  the  spine  of  that  bone,  as  far  as  the  pubis,  into 
the  linea  innominata  of  which  it  is  inserted  ;  here  also  it 
is  inseparably  joined  to  the  conjoined  tendons  of  the  inter- 
nal oblique  and  transverse  muscles  ;  as  this  fascia  is  pass- 
ing anterior  to  the  iliac  or  femoral  vessels,  a  portion  of  it 
extends  beneath  Poupart's  ligament,  in  front  of  these  ves- 
sels, so  as  to  form  the  anterior  part  of  their  sheath ;  this  pro- 
cess of  the  fascia  transversalis  soon  becomes  thin  and  in- 
distinct, and  is  lost  in  the  cribriform  part  of  the  fascia  lata. 
The  fascia  iliaca  is  a  tolerably  strong  aponeurosis  ;  it  co- 
vers the  iliac  and  psoas  muscles,  passes  behind  the  iliac 
vessels,  and  adheres  to  the  upper  margin  of  the  pelvis  ;  ex- 
ternally it  is  connected  to  the  inner  edge  of  the  ilium,  and 
inferiorly  it  is  attached  to  Poupart's  ligament,  and  to  the 
fascia  transversalis,  from  the  spine  of  the  ilium  as  far  in- 
wards as  the  iliac  artery ;  here  it  presents  a  semilunar 
edge,  separates  from  Poupart's  ligament,  and  from  the  fas- 
cia transversalis,  passes  behind  the  femoral  vessels,  forms 
the  posterior  part  of  the  sheath,  adheres  to  the  pubis,  and  to 
the  capsule  of  the  hip  joint,  and  is  connected  to  and  conti- 
nuous with  the  pubic  or  pectinseal  portion  of  the  fascia 
lata.  The  fasciae  transversalis  and  iliaca  may  be  com- 
pared to  a  funnel,  containing  in  the  superior  wide  portion 
the  peritonaeum  and  its  contents,  and  enclosing  in  the  in- 
ferior narrow  part,  or  pipe,  the  femoral  vessels,  and  one  or 
two  lymphatic  ganglia  ;  of  this  funnel  the  fascia  transver- 
salis forms  the  anterior,  and  the  fascia  iliaca  the  posterior 
wall ;  these  fasciae  may  now  be  seen  to  be  perfectly  conti- 
nuous with  each  other,  between  the  vessels  and  the  spine 
of  the  ilium,  different  names  only  being  applied  to  differ- 
ant  portions  of  one  extensive  aponeurosis  ;  as  the  iliac  and 
transverse  fasciae  are  continued  one  into  the  other,  exter- 
nal to  the  iliac  artery,  a  white  line  may  be  observed  ;  this 
is  the  circumflex  ilii  artery  enclosed  in  a  sort  of  canal  be- 
tween these  fascice  and  Poupart's  ligament,  to  which  these 
aponeuroses  are  united. 

The  student  should  next  consider  how  the  space,  com- 
monly called  the  crural  arch,  is  naturally  filled  ;  that  por- 
tion of  it  between  the  spine  of  the  ilium  and  the  iliac  or 
femoral  artery  is  occupied  by  the  psoas  and  iliac  muscles ; 
imbedded  between  these  muscles  is  the  anterior  crural 
nerve ;  on  the  pubic  side  of  these  muscles  is  the  femoral 
artery,  next  to  which  is  the  femoral  vein,  and  at  a  little 
distance  to  the  pubal  side  of  this  vessel  is  Gimbernaut's 
ligament,  which  closes  the  internal  part  of  this  space ;  thus, 
almost  all  the  crural  arch  is  filled,  except  a  small  portion 


154  DUBLIN    DISSECTOR. 

between  the  femoral  vein  and  the  third  insertion  of  Pou- 
part's  ligament;  this  space  is  the  femoral  or  crural  ring; 
this  is  somewhat  of  a  triangular  form,  the  base,  externally, 
is  the  femoral  vein,  the  apex  internally  is  Gimbernaut's 
ligament ;  it  is  bounded  anteriorly  by  Poupart's  ligament, 
and  by  the  superior  fibres  or  cornu  of  the  falciform  pro- 
cess of  the  fascia  lata,  and  posteriorly  by  the  pubis,  cover- 
ed by  the  pectinseal  muscle,  and  by  the  pectina3al  portion 
of  the  fascia  lata ;  the  spermatic  cord  or  the  ligamenturn 
teres  lies  on  the  anterior  boundary  of  this  opening,  Gim- 
bernaut's ligament  prevents  femoral  hernia  occurring  in- 
ternal to  this  space,  which  is  the  only  part  in  the  crural 
arch  where  a  hernia  can  descend,  and  even  here  this  acci- 
dent is  in  a  great  degree  guarded  against,  as  a  lymphatic 
ganglia  generally  occupies  this  situation,  and  a  layer  of 
condensed  cellular  membrane  extends  across  the  opening  ; 
this  must  be  carried  down  before  the  hernial  sac,  so  as  to 
form  a  covering  for  it,  and  hence  it  has  been  named  the 
fascia  propria;  this  fascia,  though  often  weak  and  indis- 
tinct in  the  natural  and  healthy  state,  becomes  very  thick 
and  strong  in  cases  of  old  femoral  hernia  :  the  fascia  pro- 
pria may  be  described  as  arising  thin  and  delicate  from 
the  fascia  iliaca  on  the  external  side  of  the  iliac  vessels  ; 
passing  over  these  vessels  it  descends  internally  into  the 
pelvis;  inferiorly  it  is  continued  along  these  vessels  to 
Poupart's  ligament,  covers  the  femoral  ring,  and  then  as- 
cending'is  lost  on  the  inner  surface  of  the  fascia  transver- 
salis.  Crural  hernia  cannot  occur  external  to  the  ring, 
as  there  the  femoral  vessels  fill  up  the  space,  and  strong 
partitions  pass  from  the  fascia  transversalis  to  the  fascia 
iliaca  on  the  inner  side  of  the  vein,  and  between  it  and  the 
artery ;  these  septa  prevent  the  distention  of  the  sheath ; 
the  fascia  propria  also  rounds  off  the  angle  betwreen  the 
fascia  transversalis  and  the  forepart  of  the  vessels,  and 
prevents  a  hernia  occurring  in  front  of  the  artery  or  vein  ; 
external  to  these  vessels  the  crural  arch  is  completely 
closed  by  the  close  connexion  between  the  fasciaa  trans- 
versalis and  iliaca  and  Poupart's  ligament,  in  front  of  the 
psoas  and  iliac  muscles.  Femoral  hernia  then  can  occur 
only  at  the  femoral  or  crural  ring ;  this  disease  is  more 
frequent  in  the  female  than  in  the  male,  the  crural  arch 
and  ring  being  larger  in  the  former  than  in  the  latter; 
femoral  hernia  descends  through  a  sort  of  canal  which 
commences  at  the  crural  ring,  and  ends  at  the  saphenic 
opening  in  the  fascia  lata,  through  which  the  sac  pro- 
trudes ;  the  hernial  sac  in  descending  carries  before  it  the 
fascia  propria,  descends  in  the  sheath  of  the  vessels  along 
the  inner  side  of  the  vein,  and  may  remain  in  this  situa- 


DUBLIN    DISSECTOR.  155 

tion  for  a  considerable  time ;  as  the  tumour  increases  in 
size  it  bursts  through  the  sheath,  and  either  tears  or  dilates 
some  opening  in  the  cribriform  fascia,  and  then  turns  for- 
wards into  the  groin  ;  if  the  tumour  increase  still  further,  it 
is  found  to  turn  upwards  over  Poupart's  ligament,  and  to  rest 
on  the  lower  part  of  the  tendon  of  the  external  oblique  ;  the 
form  of  the  crural  ring,  the  course  of  the  superficial  epigas- 
tric vessels,  and  the  close  connexionfl&etween  the  superficial 
and  cribriform  fasciae  account  for  its  ascending  in  this 
manner.  If  we  dissect  off  the  integuments  from  a  femoral 
hernia  of  long  standing,  we  shall  find  beneath  them  the 
superficial  fascia  so  increased  in  thickness  and  vase ularity 
as  to  present,  a  compact  and  almost  fleshy-like  appearance  ; 
when  this  shall  have  been  divided,  the  tumour  can  be 
brought  down  off  the  abdomen  into  the  groin,  and  will  be 
found  covered  by  a  dense  and  smooth  capsule,  which  often 
presents  a  glossy  appearance  ;  this  is  the  fascia  propria ; 
in  dissecting  off  this,  it  will  in  general  be  found  to  consist 
of  several  laminae,  which  sometimes  separate  so  easily  and 
appear  so  distinct  as  to  lead  an  inexperienced  operator  to 
suppose  that  the  hernial  sac  itself  is  exposed.  These  then 
are  the  coverings  of  the  sac,  which  is  thus  placed  external 
or  superficial  to  the  fascia  lata :  the  neck  of  the  sac,  how- 
ever, it  is  to  be  recollected,  lies  deep  within  the  sheath  of 
the  vessels,  and  is,  therefore,  covered  by  the  fascia  trans- 
versalis,  and  by  the  superior  cornu  of  the  falciform  pro- 
cess of  the  fascia  lata.  Let  the  student  now  review  the 
dissection  that  has  been  made ;  let  him  move  the  thigh  in 
different  directions,  and  he  will  remark  that,  when  it  is  ro- 
tated inwards,  Poupart's  and  Gimbernaut's  ligaments,  as 
well  as  the  fascia  lata  feel  relaxed,  and  that  the  crural 
ring  will  feel  larger  or  more  dilatable ;  let  him  also  ob- 
serve the  relation  of  the  femoral  vein,  the  epigastric  ves- 
sels and  the  spermatic  cord  or  round  ligament  to  this  open- 
ing ;  pass  up  the  finger  from  the  groin  into  the  crural  ring, 
and  suppose  that  the  stricture  on  femoral  hernia  was  seat- 
ed here,  and  that  this  opening  required  to  be  dilated,  he 
will  now  perceive  that  this  may  be  done  with  most  safety 
by  directing  the  edge  of  the  bistoury  forwards  and  a  little 
inwards,  so  as  to  divide  the  external  edge  or  base  of  Gim- 
bernaut's ligament,  which  edge  is  composed  of  the  inser- 
tion of  the  superior  cornu  of  the  falciform  process  of  the 
fascia  lata  ;  the  stricture  on  femoral  hernia  may,  however, 
be  seated  lower  down  than'in  the  neck  of  the  sac ;  it  may 
be  situated  in  that  opening  of  the  cribriform  fascia  through 
which  the  hernial  sac  has  protruded  ;  in  such  a  case,  the 
stricture  may  be  divided  by  directing  the  edge  of  the  knife 
directly  inwards  along  the  surface  of  the  pectinseus  muscle 


156  DUBLIN    DISSECTOR. 

The  following  measurements  of  the  parts  engaged  in, 
or  referred  to  in  the  foregoing  account  of  the  anatomy  of 
the  inguinal  and  femoral  hernisehave  been  extracted  from 
Cooper's  valuable  work  on  Hernia,  and  have  been  sanc- 
tioned by  several  other  writers  on  the  same  subject :  I  have 
tested  these  very  frequently,  and  though  I  can  bear  testi- 
mony to  their  general  accuracy,  I  must  observe,  I  have 
found  deviations  to  have  occurred  so  frequently,  and  in 
cases  where  there  was  no  a  priori  reason  to  expect  such, 
that  I  do  not  consider  these  numbers  as  facts  of  much  value, 
or  of  any  material  practical  importance. 

Male.  Female. 
From  the  symp.  pubis  to  the  ant.  sup.  spinous  process  of  the 

ilium, 5i|  in.    6  in. 

to  the  tuberosity  of  pubis,   -    -    1£  1| 

to  the  inner  margin  of  ext.  ab- 

abdominal  ring,       -    -    -    -    OJ  1 

to  the  inner  edge  of  internal 
abdnm.  ring,  ------3  3 

to  the  middle  of  iliac  artery,    3£  3$ 

to  the  middle  of  iliac  vein,      -    2|  2$ 

to  the  origin  of  epigastric  ar- 
tery, --------         3  3^ 

to  the  epig.  art.  on  the  inner 

edge  of  ext.  abdoin.  ring,     -    2$  2£ 

to  the  middle  of  lunated  edge 

of  fascia  lata,     -----    3^  »$ 

to  the  middle  of  crural  ring,    -    2j  2| 

From  ant.  edge  of  crural  arch  to  saphona  major  vein,   -----    i  j| 

From  symp.  pubis  to  centre  of  oririce  of  femoral  hernia!  sac,    -    -    2  2j 

From  centre  of  orilice  of  do.  to  external  iliac  artery,    -----    i  j| 

to    centre  of   ext.    iliac 

vein, -    0£  0$ 

to    origin  of   epigastric 

artery,       -----    oif  1 

to  inner  edge  of  int.  ab- 
dominal ring,      -    -    -    1  ij. 
From  tuberosity  of  pubis  to  centre  of  orifice  of  fern,  hernial  .sac,  .    1              l£ 

(.Inat.  and  Surg.  Treatment  of  Jbdom.  Hernia^  by  Sir  A.  COOPER.  Bart.   2nd 
edit,  by  C.  A.  Keys.) 


SECTION  II. 

DISSECTION    OF    THE    VISCERA    OF    THE    ABDOMEN. 

THE  abdomen  is  the  largest  cavity  in  the  body ;  it  is  of 
an  oval  form  ;  its  capacity,  and  in  some  degree  its  figure, 
differ  at  different  ages  and'in  different  subjects ;  it  is  bound- 
ed superiorly  by  the  diaphragm,  anteriorly  and  laterally 
by  the  abdominal  muscles,  inferiorly  by  the  true  and  false 
pelvis,  and  posteriorly  by  the  lumbar  vertebrae,  the  crura 
of  the  diaphragm,  and  the  psoae  and  quadrati  lumborum 
muscles.  Although  the  expression  "cavity  of  the  abdo- 


DUBLIN    DISSECTOR.  157 

men"  is  in  common  use,  it  is  not  correct,  for  during  life 
there  is  no  cavity,  as  the  diaphragm  and  abdominal  muscles 
by  their  alternate  action  keep  up  such  a  constant  and  uni- 
form pressure  on  the  viscera,  that  these  and  the  parietes  are 
always  in  perfect  contact.  The  abdomen  contains  the  per- 
itonaeum and  the  organs  of  digestion ;  the  kidneys,  renal 
capsules  and  ureters;  also  the  thoracic  duct,  the  sympa- 
thetic nerves,  the  aorta,  vena  cava,  and  the  numerous 
branches  of  these  vessels.  The  abdomen  is  generally  di- 
vided by  writers  into  nine,  but  by  some  into  twelve  re- 
gions ;  by  drawing  two  transverse  lines,  one  between  the 
extremities  of  the  cartilages  of  the  ninth  ribs,  and  the  other 
between  the  anterior  superior  spinous  processes  of  the  ossa 
ilii,  we  may  define  three  regions ;  the  epigastric  above,  the 
umbilical  in  the  middle,  and  the  hypogastric  below ;  and 
then  by  drawing  a  vertical  line  on  each  side  from  the  ex- 
tremity of  the  ninth  rib  to  the  anterior  superior  spinous 
process  of  the  ilium,  we  shall  subdivide  each  of  these  re- 
gions into  three  parts :  the  three  divisions  of  the  epigastric 
region  are  the  epigastrium,  or  scrobiculus  cordis  in  the  cen- 
tre, and  the  right  and  left  hypochondriac  regions  on  either 
side:  the  epigastrium  is  immediately  below  the  ensiform 
cartilage,  and  the  hypochondriac  regions  are  covered  by 
the  false  ribs ;  the  lateral  portions  of  the  umbilical  division 
are  the  lumbar  regions ;  the  middle  of  the  hypogastric  re- 
gion is  the  hypogastrium,  and  the  lateral  portions  are  the 
iliac  regions ;  the  lower  part  of  the  hypogastrium  is  called 
by  some  the  pubic  region,  and  the  lower  part  of  each  iliac 
division  is  called  inguinal  region,  or  more  properly  spermatic, 
(the  term  inguinal  being  commonly  applied  to  the  upper 
and  anterior  part  of  the  thigh,)  and  contains  the  iliac  ves- 
sels, and  in  the  male  the  spermatic  cord,  and  in  the  female 
the  round  ligament  of  the  uterus. 

The  viscera,  which  constantly  or  occasionally  occupy 
the  regions  of  the  abdomen  will  be  seen  when  the  peri- 
tonseal  cavity  has  been  opened,  and  with  these  the  student 
should  make  himself  familiar,  as  this  knowledge  may  be 
of  practical  importance  in  cases  of  wounds  penetrating 
this  cavity,  or  in  making  an  examination  during  life 
to  detect  any  suspected  organic  disease.  Dissect  the 
abdominal  muscles  off'  the  peritonaeum;  these  can  be 
easily  separated  laterally  and  inferiorly;  but  anterior- 
ly, particularly  near  the  umbilicus,  it  will  be  found 
very  difficult  to  detach  the  sheath  of  the  rectus  from  this 
membrane.  The  external  surface  of  the  peritoneum, 
which  is  thus  exposed,  appears  rough  and  cellular,  from  its 
connexion  to  the  superincumbent  muscles  ;  three  ligamen- 
tous  cords  are  seen  extending  along  it  anteriorly  and  infe- 
14 


158  DUBLIN    DISSECTOR. 

riorly,  from  the  summit  and  sides  of  the  urinary  bladder 
towards  the  umbilicus ;  the  central  one  of  these  is  the  re- 
mains of  the  urachus,  and  that  on  each  side  is  the  obliter- 
ated umbilical  or  hypogastric  artery ;  anteriorly  and  su- 
periorly we  perceive  another  ligamentous  substance,  as- 
cending from  the  umbilicus  obliquely  backwards,  and  to 
the  right  side ;  this  is  the  remains  of  the  umbilical  vein ; 
it  is  at  first  placed  between  the  peritonaeum  and  the  mus- 
cles, but  it  soon  sinks  deep  towards  the  liver,  carrying 
around  it  a  fold  of  peritonaeum,  named  the  suspensory  liga- 
ment of  the  liver,  which  will  be  seen  when  the  peritonaeum 
is  opened ;  the  epigastric  vessels  also  may  be  observed  as- 
cending from  each  inguinal  region,  and  branches  of  the 
internal  mammary  arteries  descending  on  the  surface  of 
this  membrane.  Next  open  the  peritonaeum  by  an  incision 
from  the  ensiform  cartilage  to  the  umbilicus,  and  from  this 
point  carry  another  on  each  side  obliquely  downwards,  to 
the  spine  of  the  ilium  :  on  throwing  down  the  inferior  flap 
thus  formed,  we  remark  on  its  internal  surface  the  projec- 
tions of  the  three  ligamentous  cords  which  were  before 
noticed  as  ascending  from  the  bladder  to  the  umbilicus ; 
we  may  also  remark  how  the  external  of  these  cords,  or 
the  obliterated  umbilical  artery  on  each  side,  throws  the 
lower  part  of  the  peritonaeum  into  pouches,  two  on  each 
side,  the  external  and  internal  inguinal  pouches  or  fosscc  ;  the 
former  lies  between  the  ilium  and  the  obliterated  hypogas- 
tric vessels,  the  latter  between  this  cord  and  the  fundus 
of  the  bladder.  The  external  pouch  is  large  and  very  con- 
cave internally,  and  appears  to  protrude  towards  the  in- 
guinal canal :  the  existence  of  this  pouch  may  conduce  to 
the  production  of  oblique  inguinal  as  well  as  of  femoral 
hernia :  the  internal  pouch  lies  behind  the  external  ring, 
and  becomes  protruded  in  direct  or  ventro-inguinai  hernia. 
When  the  peritonaeum  has  been  fully  opened,  we  perceive 
its  inner  surface  smooth  and  polished  like  all  serous  mem- 
branes, and  filling  its  cavity  we  see  the  numerous  digestive 
organs ;  these,  though  apparently  within  this  bag,  are  real- 
ly behind  it,  and  only  protrude  the  posterior  side  of  this 
large  sac  into  the  cavity ;  nothing  is  contained  within  the 
peritonseum  but  the  serous  fluid,  which  is  constantly  exhaled, 
for  the  purpose  of  lubricating  its  opposite  sides.  We  also 
obtain  a  partial  view  of  the  following  organs.,  which  in 
general  occupy  the  same  situation  during  life  as  we  per- 
ceive them  now  to  hold.  Filling  the  right  hypochondrium 
is  the  liver,  with  the  fundus  of  the  gall  bladder  projecting 
a  little  below  it.  In  the  epigastric  region  we  see  a  portion 
of  the  liver  also,  resting  on  the  stomach,  and  below  it  we 
see  the  pylorus  and  the  commencement  of  the  duodenum ; 


DUBLIN    DISSECTOR.  159 

in  the  left  hyponchondrium  lie  the  spleen  and  great  ex- 
tremity of  the  stomach ;  in  the  right  and  left  lumbar  re- 
gions we  find  the  colon,  ascending  through  the  former,  and 
descending  through  the  latter,  behind  which  is  each  kidney ; 
the  duodenum  also  partly  occupies  the  right  lumbar  region ; 
through  the  proper  umbilical  region  the  transverse  colon 
runs,  not  fixed,  however,  in  any  particular  part  of  it,  and 
from  this  intestine  we  perceive  the  great  omentum  descend- 
ing towards  the  lower  part  of  the  abdomen,  presenting, 
however,  very  different  appearances  in  different  subjects : 
in  some  being  expanded  over  the  small  intestines,  so  as 
nearly  to  conceal  them ;  in  others  being  coiled  up  into  a 
narrow  fold,  and  often  concealed  in  some  recess  between 
the  surrounding  viscera :  the  convolutions  of  the  jejunum 
and  ileum  intestines  occupy  the  lower  part  of  the  umbilical, 
and  extend  indifferently  into  the  hypogastric,  and  iliac  re- 
gions ;  the  csecum  or  caput  coli  is  fixed  in  the  right,  and 
the  sigmoid  flexure  of  the  colon  in  the  left  iliac  fossa ;  the 
rectum  and  other  pelvic  viscera  occupy  the  hypogastric 
regions,  but  will  of  course  change  their  own  situation  as 
well  as  that  of  the  small  intestines,  according  as  they  are 
contracted  or  distended.  The  student  may  next  examine 
the  anatomy  of  the  peritonaeum;  this  is  the  largest  serous 
sac  or  membrane  in  the  body  ;  it  lines  the  abdominal  mus- 
cles, and  covers  almost  all  the  abdominal  viscera ;  that 
portion  which  adheres  to  the  parietes  is  called  the  parietal, 
and  that  covering  the  viscera  the  visceral  layer.  The  peri- 
tonaeum is  a  shut  sac,  and  therefore,  when  opened  presents 
one  continued  surface,  which  may  be  traced  throughout 
the  whole  extent  without  any  interruption ;  it  covers  the 
viscera  in  such  a  manner  that  they  lie  external  or  pos-. 
terior  to  it ;  the  familiar  example  of  the  double  night-cap 
on  the  head  has  been,  not  unaptly,  adduced,  to  explain  how 
the  viscera  may  be  covered  by  the  peritonaeum,  and  yet 
really  lie  beneath  it  or  behind  it.  Let  us  now  trace  this 
membrane  through  its  entire  extent,  commencing  at  the 
umbilicus ;  from  the  transverse  incision  that  was  made  into 
it  in  this  situation,  we  may  perceive  it  to  ascend  on  the  in- 
ternal surface  of  the  transverse  and  recti  muscles,  as  high 
as  the  margin  of  the  thorax  ;  then  bending  back,  it  adheres 
to  the  inferior  surface  of  the  diaphragm,  and  continues 
very  far  back  on  this  muscle,  particularly  in  the  left  hy- 
pochondrium ;  from  the  diaphragm  it  is  reflected  on  the 
spleen  on  the  left  side,  on  the  stomach  in  the  centre,  and 
on  the  liver  on  the  right  side ;  it  is  also  reflected  on  this  last 
named  viscus  by  a  distinct  fold,  the  falciform  or  suspenso- 
ry ligament,  from  the  umbilicus,  and  from  the  abdominal 
muscles  on  the  right  side  of  the  linea  alba ;  as  the  perito- 


160  DUBLIN    DISSECTOR. 

nseum  is  reflected  from  the  diaphragm  on  each  side  of  these 
organs  in  the  epigastric  and  hypochondriac  regions,  it 
forms  folds,  which  to  a  certain  extent  serve  as  ligaments  ; 
these  will  be  noticed  more  particularly  in  the  examination 
of  the  individual  viscera. 

Having  covered  the  organs  in  the  upper  division  of  the 
abdomen,  it  is  continued  downwards  in  the  following  man- 
ner :  having  invested  both  surfaces  of  the  liver  as  far  as 
its  transverse  fissure ;  it  is  conducted  along  and  around  the 
vessels  of  this  gland  towards  the  lesser  curvature  of  the 
stomach  ;  this  fold,  which  thus  surrounds  the  hepatic  ves- 
sels, is  called  the  lesser  or  the  gastro-hepatic  omentum ;  it 
is  also  sometimes  named  the  capsule  of  Glisson ;  at  the 
lesser  arch  of  the  stomach  the  two  laminae  of  this  process 
separate  to  enclose  the  stomach,  the  posterior  layer  giving 
a  serous  covering  to  the  back  part  of  this  organ,  and  in 
like  manner  the  anterior  layer  covering  its  anterior  sur- 
face, on  which  it  is  continuous  with  that  portion  of  perito- 
naeum \vhich  has  descended  from  the  diaphragm,  and  with 
that  which  is  also  continued  from  the  spleen  to  the  sto- 
mach. The  peritonsenm  having  thus  enclosed  the  stomach 
and  its  vessels  between  the  two  layers  of  the  lesser  omen- 
tum, we  next  observe  that  these  laminae  having  passed  the 
great  curvature  of  the  stomach  touch  each  other,  and  being 
joined  by  the  peritonaeum  from  the  lower  end  of  the 
spleen,  descend  under  the  name  of  the  gastro-colic  or  the 
great  omentum,  to  the  lower  part  of  the  abdomen :  in  ge- 
neral it  descends  lower  on  the  left  side  than  on  the  right ; 
it  then  turns  on  itself,  and  ascends  obliquely  backwards  to 
the  arch  of  the  colon,  along  the  convex  edge  of  which  its 
laminae  separate  to  enclose  this  intestine  and  its  vessels ; 
along  the  concave  edge  of  the  colon  these  laminae  again 
unite,  and  increasing  in  density  form  that  process  which 
is  called  the  transverse  meso-colon,  which  passes  back- 
wards to  the  spine :  opposite  the  duodenum  this  process 
separates  into  an  ascending  and  descending  layer ;  the  in- 
ferior division  of  the  duodenum  lies  between  these  ;  the 
ascending  layer  proceeds  in  front  of  the  lower  and  middle 
divisions  of  the  duodenum,  up  to  the  back  part  of  the  right 
lobe  of  the  liver,  where  it  becomes  continuous  with  the 
peritonseal  tunic  of  that  viscus  and  with  the  posterior  layer 
of  the  lesser  omentum  which  is  descending  along  the  back 
part  of  the  hepatic  vessels.  The  descending  layer  of  the 
transverse  meso-colon  expands  into  each  lumbar  region, 
in  which  it  attaches  the  lumbar  portions  of  the  colon  by  a 
duplicature  called  the  right  and  left  lumbar  meso-colon ; 
in  the  centre  the  inferior  layer  of  the  transverse  meso-co- 
lon adheres  to  the  vertebral  column,  and  to  the  great  ves- 


DUBLIN    DISSECTOR.  161 

sels  which  lie  upon  it,  and  is  thence  reflected  forwards  and 
downwards,  over  the  small  intestines  and  their  vessels, 
and  returns  around  these  to  the  spine,  thus  forming  a  very 
important  and  remarkably  folded  or  plaited  process  named 
the  mesentery.  From  the  inferior  surface  of  the  mesen. 
tery  the  peritonaeum  extends  into  either  iliac  region,  and 
descends  into  the  pelvis  in  the  middle ;  it  serves  to  connect 
the  caecum  in  the  right,  and  the  sigmoid  curve  of  the  co- 
lon in  the  left  iliac  fossa ;  in  the  pelvis  the  peritonaeum 
descends  around  the  rectum,  forming  the  process  named 
the  meso-rectum ;  opposite  the  lower  third  of  the  sacrum, 
it  is  reflected  to  the  lower  and  back  part  of  the  bladder, 
and  in  the  female  to  the  upper  and  back  part  of  the  vagi- 
na, from  which  it  ascends  on  the  uterus,  and  forms  on  each 
side  of  this  organ  the  broad  ligament  which  supports  the 
Fallopian  tube  and  the  ovary  ;  the  peritonaeum  is  then  re- 
flected from  the  fore  part  of  the  uterus  to  the  back  of  the 
bladder,  ascends,  both  in  the  male  and  female,  along  the 
posterior  surface  and  sides  of  this  viscus  to  its  superior 
fundus,  from  which,  and  from  the  iliac  fossae,  it  is  conti-. 
nued  to  the  abdominal  muscles ;  forms  the  inguinal 
pouches,  and  may  then  be  traced  on  the  inner  surface  of 
the  recti  and  transverse  muscles  up  to  the  umbilicus,  where 
the  sac  was  opened.  The  different  folds  which  the  perjto, 
naeum  forms  in  this  course  are  termed  processes,  the  prin- 
cipal  of  which,  in  addition  to  the  ligaments  of  the  several 
organs,  which  shall  be  noticed  in  the  description  of  the 
latter,  are  the  lesser  omentum,  the  great  omentum,  the 
splenic  omentum,  the  colic  omentum,  the  appendices  epi-. 
ploicae,  the  transverse,  and  the  right  and  left  lumbar  meso- 
colons,  the  mesentery,  meso-caecum  and  meso-rectum. 

The  lesser  or  gastro-hepatic  omentum  consists  of  two  lamU 
nse,  which  extend  from  the  transverse  fissure  of  the  liver 
to  the  lesser  curvature  of  the  stomach  and  to  the  upper 
part  of  the  duodenum ;  it  contains  between  its  layers  the 
vessels  of  the  liver,  viz.  the  hepatic  artery  to  the  left  side, 
the  ductus  choledochus  to  the  right,  and  the  vena  portse 
behind  and  between  both  ;  at  its  connexion  to  the  stomach, 
it  encloses  the  coronary  vessels  of  this  organ  ;  the  lesser 
omentum  lies  anterior  to  the  foramen  of  Winslow ;  this 
omentum  seldom  contains  much  fat. 

/The  great  or  gastro-colic  omentum  also  consists  of  two  la- 

/minse,  which  descend  from  the  lower  end  of  the  spleen,  and 

from  the  anterior  and  posterior  surface  of  the  stomach ; 

between  these  laminae  are  several  long  and  tortuous  ves-» 

sels,  descending  from  the  vessels  of  the  stomach,  and  some 

adipose  substance,  the  quantity  of  which  varies  very  much 

in  different  subjects ;  the  great  omentum  descends  in  front 

14* 


162  DUBLIN    DISSECTOR. 

of  the  large  and  small  intestines  to  the  lower  part  of  the 
abdomen,  in  general  lower  on  the  left  than  on  the  right 
side  ;  (this  explains  the  reason  why  the  omentum  is  more 
frequently  found  in  a  hernial  sac  on  the  left  than  on  the 
right  side ;)  it  then  turns  upwards  and  backwards  until  it 
reaches  the  transverse  arch  of  the  colon ;  that  portion  of 
omentum,  therefore,  which  is  inferior  to  the  colon,  consists 
of  four  laminae,  two  descending  and  two  ascending  ;  these, 
in  the  young  subject,  can  be  separated  from  each  other, 
and  a  distinct  cavity  can  be  seen  between  them ;  this  is 
part  of  the  cavity  or  bag  of  the  omentum  which  communi- 
cates with  the  general  cavity  of  the  peritonaeum  by  the 
opening  of  Winslow,  and  which  will  be  more  particularly 
described  presently  ;  at  the  arch  of  the  colon  the  two  as- 
cending laminae  of  the  great  omentum  separate  to  enclose 
this  intestine,  and  again  uniting,  form  the  commencement 
of  the  following  process. 

The  transverse  meso-colon  extends  from  the  concave  bor- 
der of  the  arch  of  the  colon  backwards  to  the  spine  ;  this 
process  is  very  strong  and  dense,  it  encloses  the  vessels  of 
the  colon  and  forms  a  sort  of  division  or  partition  in  the 
abdomen  between  the  epigastric  and  umbilical  regions  ; 
when  the  transverse  meso.colon  has  arrived  at  the  spine,  its 
two  laminae  separate,  one  descends,  the  other  ascends  ;  the 
descending  layer  is  very  strong,  expands  laterally  into  the 
right  and  left  lumbar  regions,  in  each  of  which  it  is  reflect- 
ed either  partially  or  perfectly  around  the  ascending  and 
descending  colon,  and  thus  forms  a  short  fold  or  process 
very  irregular  in  different  subjects,  termed  the  right  and 
left  lumbar  meso-colons ;  the  inferior  or  descending  layer  of 
the  transverse  meso-colon  is  continued  obliquely  down- 
wards in  the  middle  line  to  form  the  mesentery,  a  process 
which  we  shall  trace  when  we  have  pursued  the  superior 
or  ascending  layer  of  the  meso-colon  to  its  termination. 
This  lamina  is  thin  and  delicate ;  it  ascends  in  front  of 
the  inferior  and  middle  portions  of  the  duodenum,  and  of 
the  pancreas  ;  it  also  covers  the  aorta  and  vena  cava,  and 
continues  along  this  latter  vessel  to  the  liver,  on  the  Spige- 
lian  lobe  of  which  it  expands,  and  on  it  and  on  the  right 
lobe,  behind  the  foramen  of  Winslow,  it  becomes  conti- 
nuous with  the  peritonaeum,  which  has  been  reflected  on 
the  back  part  of  the  liver  from  the  diaphragm.  As  this 
ascending  layer  proceeds  in  front  of  the  pancreas,  it  is 
continuous  on  each  side  with  the  posterior  layer  of  the 
lesser  omentum  which  covers  the  back  part  of  the  stomach. 
The  ascending  layer  may  be  best  seen  and  traced  by  di- 
viding the  great  omentum  a  little  below  the  stomach,  and 
raising  this  organ  towards  the  thorax;  we  shall  thus  lay 


DUBLIN    DISSECTOR.  163 

open  the  cavity  of  the  omentum,  and  shall  be  able  to  trace 
the  parieties  of  this  bag  through  their  whole  extent. 

The  cavity  of  the  omentum  extends  from  the  transverse  fis- 
sure of  the  liver  superiorly,  to  the  lower  border  of  the 
great  omentum  inferiorly  ;  it  is  bounded  anteriorly  by  the 
lesser  omentum,  the  stomach,  and  the  anterior  or  descend- 
ing portion  of  the  great  omentum ;  inferiorly  it  is  formed 
by  the  great  omentum  turning  on  itself;  and  posteriorly  it 
is  bounded  by  the  ascending  portion  of  the  great  omentum, 
by  the  colon,  by  the  transverse  meso-colon,  and  by  the  su- 
perior or  ascending  layer  of  this  process,  which  terminates 
at  the  liver.  The  cavity  of  the  omentum  communicates 
with  the  general  peritonseal  cavity  through  the  foramen  of 
Winslow  ;  this  opening  is  situated  in  the  lower  part  of  the 
right  hypochondriac  region  just  above  the  right  lumbar ; 
it  is  somewhat  oval,  bounded  anteriorly  by  the  lesser 
omentum  and  by  the  hepatic  vessels,  posteriorly  by  the 
termination  of  the  ascending  layer  of  the  meso-colon  which 
invests  the  vena  cava,  superiorly  by  the  lobulus  caudatus 
of  the  liver,  and  inferiorly  by  the  superior  portion  of  the 
duodenum ;  if  the  membrane  composing  the  omenta  be 
perfect,  and  if  air  be  forced  through  this  opening,  it  will 
descend  behind  the  stomach,  and  will  inflate  the  omental 
cavity  ;  the  great  omentum,  however,  in  general  is  so  crib- 
riform that  this  experiment  cannot  be  performed ;  the  prin- 
cipal use  of  this  cavity  is  most  probably  to  afford  a  ser- 
ous surface  or  cavity  for  the  stomach  to  move  or  to  distend 
into  posteriorly  during  the  progress  of  digestion. 

The  splenic  omentum  extends  from  the  fissure  in  the 
spleen  to  the  great  end  of  the  stomach,  and  is  continuous 
inferiorly  with  the  great  omentum ;  the  splenic  vessels 
and  the  vasa  brevia  are  contained  between  the  laminae  of 
this  process. 

The  colic  omentum  is  a  fold  of  peritonaeum  which  de- 
scends from  the  upper  part  of  the  right  or  ascending 
colon ;  it  generally  lies  posterior  to  the  great  omentum  ;  it 
is  composed  of  two  laminae,  between  which  are  contained 
blood-vessels  and  adipose  substance. 

The  appendices  epiploica  are  attached  all  along  the  large 
intestine ;  but  principally  to  the  transverse  arch  of  the 
colon ;  they  are  small  prolongations  of  the  peritonaeum, 
filled  with  a  soft  fatty  substance  ;  they  are  never  found  at- 
tached to  the  small  intestine ;  they  vary  very  much  in  dif- 
ferent subjects  in  number  and  size;  their  use  is  not  as- 
certained. 

The  mesentery  is  the  largest  and  most  remarkable  process 
of  the  peritonaeum ;  it  is  continuous  with  the  descending 
layer  of  the  meso-colon,  and  extends  from  the  left  side  of 


164  DUBLIN    DISSECTOR. 

the  second  lumbar  vertebra  obliquely  downwards  to  the 
right  iliac  fossa ;  this  is  the  root  of  the  mesentery ;  from 
this  it  expands  very  much,  and  is  folded  round  the  jejunum 
and  ileum  intestines,  and  then  returns  again  to  the  spine  or 
to  the  inferior  surface  of  the  root ;  the  laminee  of  the  me- 
sentery can  be  easily  separated  ;  between  them  we  find  the 
mesenteric  arteries,  veins  and  nerves,  also  numerous  absor- 
bent vessels  and  ganglia  ;  the  mesentery  serves  to  support 
the  convolutious  of  the  small  intestines  and  the  numerous 
vessels  passing  to  and  from  these. 

The  meso-cacum  is  a  fold  of  peritonaeum  which  attaches 
the  caecum  to  the  right  iliac  fossa ;  this  process,  however, 
is  frequently  imperfect ;  the  posterior  portion  of  this  intes- 
tine being  sometimes  deprived  of  a  serous  coat,  and  con- 
nected to  the  iliac  muscle  by  cellular  membrane. 

The  meso-rectum  is  a  short  fold  of  peritonaeum  which  con- 
nects the  superior  portion  of  the  rectum  to  the  upper  and 
anterior  part  of  the  sacrum ;  it  encloses  the  hsemorrhoidal 
vessels  and  nerves. 

The  viscera  of  the  abdomen  are  the  digestive  and  urina- 
ry organs ;  the  former  we  shall  examine  first ;  they  may 
be  divided  into  the  membranous  and  glandular.  The 
membranous  viscera  are  the  stomach  and  intestinal  tube  ; 
the  latter  is  divided  into  the  small  and  large  intestine  ;  the 
small  intestine  is  subdivided  into  the  duodenum,  jejunum, 
and  ileum ;  the  large  intestine  into  the  ca3cum,  colon,  and 
rectum.  The  glandular  viscera  are  the  liver,  spleen,  and 
pancreas.  We  shall  consider  the  membranous  viscera  first, 
and  commence  with  the  description  of  the  stomach,  which 
is  the  most  important  part  of  the  digestive  apparatus,  the 
principal  change  in  the  food  being  accomplished  in  this 
organ. 

The  stomach  is  placed  between  the  oesophagus  and  the 
duodenum,  and  communicates  with  both ;  it  is  situated  in 
the  left  hypochondriac  and  epigastric  regions,  and  a  small 
portion  of  it  extends  into  the  right  hypochondrium  ;  from 
the  left  side  it  passes  across  the  epigastric  region,  obliquely 
downwards  and  forwards,  and  near  its  right  or  pyloric  ex- 
tremity it  bends  a  little  upwards  and  backwards.  Tho 
stomach  is  connected  to  the  diaphragm  by  the  oesophagus 
and  by  the  peritonaeum ;  to  the  spleen  by  the  splenic  omen- 
turn  ;  to  the  liver  by  the  lesser  omentum,  and  to  the  arch 
of  the  colon  by  the  great  omentum.  If  the  stomach  be 
moderately  distended  with  air  or  fluid,  its  form  and  con- 
nexions can  be  better  understood;  it  will  then  appear 
somewhat  of  a  conical  figure,  the  base  to  the  left  side,  the 
apex  to  the  right,  the  intermediate  part  being  somewhat 
curved ;  it  will  present  two  extremities,  the  left  and  right ; 


DUBLIN    DISSECTOR.  165 

two  orifices,  the  cardiac  and  pyloric  [or  cesophageal  and 
duodenal ;]  two  surfaces,  an  anterior  or  superior,  a  poste- 
rior or  inferior ;  and  two  curvatures  or  edges,  the  lesser  or 
concave,  the  greater  or  convex.  The  left  or  splenic  extremity 
is  very  large,  swells  into  the  left  hypochondrium  beneath 
the  ribs,  so  as  nearly  to  conceal  the  spleen ;  the  right  or 
pyloric  extremity  is  much  smaller,  is  cylindrical  and  slightly 
convoluted  like  an  intestine ;  it  lies  anterior  and  inferior  to 
the  left  or  splenic  end,  and  extends  to  the  fundus  of  the 
gall  bladder  or  to  the  edge  of  the  lobulus  quadratus  of  the 
liver;  it  sometimes  descends  into  the  umbilical  region. 
The  cardiac  orifice  is  the  highest  point  of  the  stomach  ;  it  is 
situated  between  the  left  or  great  end  and  the  lesser  cur- 
vature, about  three  inches  distant  from  the  former ;  it  is 
surrounded  by  vessels  and  nerves. 

The  pyloric  orifice  is  between  the  stomach  and  the  duode- 
num ;  it  lies  to  the  right  side  of  the  spine ;  it  is,  in  general, 
in  contact  with  the  liver  and  gall-bladder,  and  anterior  to 
the  pancreas ;  it  lies  inferior,  anterior,  and  to  the  right  side 
of  the  cardiac  orifice ;  it  has  a  peculiar  firm,  hard  feel. 
The  anterior  surface  looks  upwards  aud  forwards,  and  is  in 
contact  with  the  diaphragm,  the  ribs  and  the  left  lobe  of 
the  liver.  The  posterior  surface  looks  backwards  and  down- 
wards, and  rests  on  the  meso-colon.  The  lesser,  or  concave 
edge  of  the  stomach,  looks  backwards  and  upwards  to- 
wards the  spine  and  lobulus  Spigelii  of  the  liver ;  this  edge, 
near  the  pylorus,  is  convex,  the  great  edge  being  concave 
opposite  to  this  ;  the  lesser  omentum  is  attached  to  it,  and 
the  coronary  vessels  run  along  it.  The  great  or  convex  edge 
looks  forwards  and  downwards  towards  the  colon;  to  it 
the  great  omentum  and  the  epiploic  vessels  are  attached  : 
in  the  empty  or  contracted  state  of  the  stomach,  these  edges 
are  thin  and  directed  almost  vertically,  but  when  the 
stomach  is  distended,  they  become  enlarged  and  round, 
and  continuous  with  the  surfaces. 

The  stomach  is  composed  of  three  tunics,  a  serous,  a 
muscular,  and  a  mucous  ;  these  are  connected  to  each  other 
by  two  laminse  of  cellular  membrane ;  the  serous  or  peri- 
ton&al  coat  is  derived,  as  was  before  explained,  from  the  la- 
minse of  the  lesser  omentum,  separating  at  the  lesser  cur- 
vature, expanding  over  its  surfaces,  and  uniting  along  the 
convex  edge,  to  form  the  great  omentum :  the  serous  coat 
is  loosely  united  to  the  edges,  but  almost  inseparably  so  to 
the  middle  of  each  surface  and  to  the  pyloric  extremity ;  a 
layer  of  very  fine  cellular  tissue  connects  this  to  the  fol- 
lowing tunic,  the  muscular ;  this  consists  of  fibres,  which 
run  in  three  different  directions ;  the  first  or  superficial  are 
longitudinal ;  they  are  continued  from  the  oesophagus,  and 


166  DUBLIN    DISSECTOR. 

are  very  strong  along  the  curvatures,  particularly  on  the 
lesser ;  the  middle  layer  of  fibres  run  circularly ;  they 
commence  at  the  left  extremity,  or  cul  de  sac,  and  are  ar- 
ranged in  nearly  parallel  rings;  they  are  very  strong 
about  the  centre,  where  they  often  cause  a  constricted  ap- 
pearance around  the  stomach,  as  if  dividing  it  into  two  por- 
tions; the  circular  fibres  again  increase  in  thickness  as 
they  approach  the  pylorus :  these  fibres  do  not  form  per- 
fect circles ;  the  extremities  of  each  fasciculus  turn  ob- 
liquely to  one  side  ;  the  third  set  of  fibres  take  a  very  irre- 
gular or  oblique  direction ;  they  are  most  distinct  on  the 
great  end,  or  culde  sac,  and  appear  as  a  continuation  of  the 
circular  fibres  of  the  oesophagus.  Beneath  the  muscular 
tunic  is  the  second  lamina  of  cellular  tissue,  which  con- 
tains the  minute  divisions  of  the  nerves  and  vessels  of  the 
stomach,  and  has  been,  by  some,  called  the  nervous  coat 
of  the  stomach.  The  internal,  or  mucous  or  villous  coat  is 
very  soft,  and  of  a  pale  red  or  rose  colour,  sometimes  in- 
terspersed with  such  very  vascular  patches  as  might  lead 
the  inexperienced  to  mistake  them  for  the  effects  of  inflam- 
mation :  in  order  to  examine  this  tunic  of  the  stomach,  this 
organ  should  be  removed  from  the  subject,  everted  and 
washed.  This  membrane  will  be  found  covered  with  a 
viscid  fluid,  and  thrown  into  numerous  rugse,  and  will  ap- 
pear very  different  from  that  lining  the  oesophagus ;  at  the 
pylorus  it  forms  a  circular  fold,  [the  phylosie  valve]  which 
is  thin  and  floating  ;  external  to  this  is  a  circular  fasciculus 
of  muscular  fibres,  which  have  a  peculiar  dense  feel :  this 
fold  of  mucous  membrane  narrows  the  opening  into  the 
duodenum,  and  when  assisted  by  the  surrounding  muscular 
fibres,  can  perfectly  intercept  the  passage  from  the  stomach 
into  the  intestine ;  in  the  cellular  tunic,  external  to  this 
membrane,  particularly  along  the  curvatures,  are  many 
small  mucous  glands,  which  open  on  the  mucous  surface ; 
these  are  the  glandules  Brunneri:  the  mucous  coat  of  the 
stomach  secretes  the  fluid  called  the  gastric  juice,  which 
is  generally  believed  to  have  the  remarkable  properties  of 
being  powerfully  solvent  and  anti-putrescent.  In  the 
stomach  the  food  undergoes  the  first  important  change  in 
digestion,  being  here  converted  into  a  soft  homogeneous 
pulpy  mass,  called  chyme. 

[Cases  have  been  recorded  of  double  and  even  triple  stomachs,  in 
the  human  subject ;  but  this  appearance  is  deceptive,  and  is  merely  the 
result  of  a  contraction  of  the  organ  at  one  or  more  points  of  its  cir- 
cumference, dividing  it  into  separate  compartments.  The  volume 
of  the  organ  differs  very  much  in  different  individuals,  and  in  the  same 
individual  under  different  circumstances.  The  average  capacity  of 
the  adult  stomach  in  a  medium  state  of  distension  is  probably  from 


DUBLIN    DISSECTOR.  167 

two  to  three  pints ;  this  capacity  however  may  be  doubled,  or  tripled 
by  distension:  as  compared  with  the  inferior  animals,  the  human 
stomach  is  smaller  than  that  of  the  herbivorous,  and  greater  than 
that  of  the  carnivorous  animals,  which  is  one  of  the  arguments  in 
favor  of  the  opinion  that  man  is  omnivorous.  The  lower  part  of  the 
stomach  sometimes  presents  a  remarkably  sacculated  appearance 
without  evidence  of  disease.] 

The  duodenum  is  the  next  portion  of  the  alimentary 
canal ;  this  is  the  first  and  shortest  division  of  the  small 
intestines ;  it  extends  from  the  pylorus  to  the  root  of  the 
mesentery,  where  the  jejunum  commences ;  it  lies  partly 
in  the  right  hypochondriac,  and  partly  in  the  right  lumbar 
and  in  the  umbilical  regions  ;  it  takes  a  semicircular  course 
around  the  head  of  the  pancreas :  this  course  may  be  di- 
vided into  three  parts ;  the  first,  or  superior  transverse ; 
the  second,  or  perpendicular,  and  the  third  or  inferior 
transverse.  The  superior  transverse  portion  ascends  from  the 
pylorus  obliquely  backwards  and  to  the  right  side,  beneath 
the  edge  of  the  liver,  so  as  to  touch  the  gall-bladder ;  here 
the  intestine  makes  a  sudden  turn,  (the  superior  angle,) 
and  the  middle  or  perpendicular  portion  of  it  commences ; 
this  descends  in  front  of  the  right  kidney,  as  low  as  the 
third  lumbar  vertebra,  where  it  makes  a  second  turn  (the 
inferior  angle)  from  which  the  inferior  transverse  portion  ex- 
tends obliquely  upwards,  and  to  the  left  side,  and  at  the 
first  lumbar  vertebra  ends  in  the  jejunum.  The  duodenum 
differs  from  the  remainder  of  the  small  intestine,  in  being 
fixed  in  its  situation,  and  being  only  partially  covered  by 
the  peritonaeum,  and  being  of  much  larger  calibre,  parti- 
cularly near  the  inferior  angle ;  its  muscular  coat  is  very 
strong,  and  the  valvulee  conniventes  very  numerous  and 
large.  The  superior  transverse  portion  is  more  contracted 
than  any  other  part  of  it ;  it  is  covered  on  both  surfaces 
by  the  peritonaeum  like  the  stomach,  and  is,  therefore, 
more  moveable  than  the  rest  of  the  intestine.  The  perpen- 
dicular portion  is  concealed  by  the  omentum,  and  by  the 
colon,  and  is  covered  by  the  ascending  layer  of  the  meso- 
colon;  this  portion  lies  on  the  right  kidney,  and  on  the 
vena  cava,  and  has  no  peritonaeum  posterior  to  it ;  it  is, 
therefore,  fixed,  and  is  dilatable  ;  the  biliary  and  pancreatic 
ducts  perforate  the  inner  side  of  this  division  of  the  duo- 
denum ;  these  pass  through  its  coats  very  obliquely,  and 
open  into  the  intestine,  sometimes  distinctly,  and  at  other 
times  conjointly,  on  a  small  papilla,  opposite  the  inferior 
angle.  The  inferior  transverse  part  of  the  duodenum 
passes  across  the  aorta  and  the  right  renal  vessels ;  like 
the  middle  portion,  it  is  only  partially  covered  by  the  peri- 
tonaeum, being  placed  between  the  layers  of  the  meso- 


168  DUBLIN    DISSECTOR. 

colon;  its  lower  border  may  be  seen  without  dissection, 
projecting  through  the  inferior  layer  of  the  meso-colon ; 
the  superior  mesenteric  vessels  pass  in  front  of  the  termi- 
nation of  this  part  of  the  duodenum,  and  appear  to  com- 
press it  against  the  aorta,  so  as  to  retard  the  passage  of  its 
contents  into  the  jejunum.  In  the  duodenum,  the  chyme 
is  mixed  with  the  biliary  and  pancreatic  fluids,  and  a  sepa- 
ration takes  place  between  the  chyle  and  the  excrementi- 
tious  part  of  the  food. 

The  jejunum  and  ileum  intestines  are  covered  by  the 
omentum :  if  we  raise  this  process  and  the  arch  of  the 
colon,  and  place  them  on  the  edge  of  the  thorax,  the  con- 
volutions of  these  intestines  will  be  seen  in  the  umbilical, 
hypogastric,  and  iliac  regions  ;  convex  anteriorly,  concave 
posteriorly,  and  attached  to  the  mesentery;  the  jejunum 
commences  in  the  left  lumbar,  and  the  ileum  ends  in  the 
right  iliac  region.  There  is  no  exact  division  between 
these  two  intestines ;  the  upper  two-fifths  are  named  the 
jejunum,  and  are  placed  higher  in  the  abdomen  than  the 
ileum,  which  is  the  name  given  to  the  three  remaining 
fifths.  The  jejunum  is  redder,  feels  thicker,  and  is  larger 
than  the  ileum,  which  is  pale  and  thin :  these  differences 
are  striking  when  we  compare  the  commencement  of  the 
jejunum  with  the  terminating  portion  of  the  ileum  ;  in  the 
intermediate  space,  however,  they  are  gradually  lost ;  they 
depend  on  the  greater  vascularity  and  number  of  valvulae 
conniventes  in  the  jejunum  than  in  the  ileum. 

The  large  intestine  forms  about  one-fifth  of  the  intestinal 
canal,  and  is  subdivided  into  the  ca3cum,  colon,  and  rectum  ; 
the  large  intestine  differs  from  the  small  not  merely  in  size, 
but  in  having  a  peculiar  cellular  and  sacculated  appearance, 
particularly  when  distended ;  small  processes  also  (the  ap- 
pendices epiploicae)  are  attached  along  its  whole  course  : 
three  strong  muscular  bands,  running  in  a  longitudinal  di- 
rection, may  also  be  observed,  chiefly  in  the  caecum  and 
colon,  they  appear  to  pucker  the  large  intestine,  so  as  to 
give  it  the  cellular  structure  before  mentioned :  these  bands, 
in  addition  to  a  muscular  property,  possess  some  elasticity 
also ;  in  some  animals  indeed  they  are  decidedly  elastic. 
The  large  intestines  are  paler  than  the  small,  and  much 
thinner,  having  but  few  valvulse  conniventes. 

The  caecum,  or  caput  coli,  is  situated  in  the  right  iliac  fossa, 
in  which  region  it  is  fixed  by  the  peritonaeum,  which  in 
general  covers  it  only  anteriorly  and  laterally,  while  cellu- 
lar membrane  connects  it  posteriorly  to  the  iliac  and  psoas 
muscles ;  in  some,  however,  the  peritoneum  covers  this 
pouch  all  round,  and  connects  it  to  the  iliac  fossa  loosely 
by  a  process  named  the  meso-csecum;  it  is  always  covered 


DUBLIN    DISSECTOR.  159 

anteriorly  by  the  abdominal  muscles,  and  sometimes  by  the 
convolutions  of  the  ileum ;  it  lies  beneath  the  right  kidney, 
and  is  continuous  with  the  ileum  and  the  colon.  The  caecum 
is  somewhat  triangular,  the  apex  below,  the  base  above  at 
the  colon,  on  its  external  surface  are  three  irregular  protu- 
berances, one  anteriorly,  and  two  posteriorly ;  from  its 
lower  and  posterior  part  a  small  tortuous  process  named 
app&idix  vermiformis,  about  the  size  of  a  goose  quill,  hangs 
into  the  pelvis ;  it  is  attached  to  and  communicates  with 
the  caecum  just  below  the  ileum ;  a  sort  of  mesentery  con- 
nects it  in  its  situation  :  its  use  is  not  ascertained. 

[The  position  of  the  appendix  is  by  no  means  invariable ;  it  some- 
times  lies  behind  the  caecum,  extending  up  towards  the  liver,  or  else 
projecting  beyond  the  caecum  on  its  right  side  ;  in  other  cases  it  lies 
behind  the  termination  of  the  ileum,  or  even  in  front  of  it.  Intestinal 
worms  have  been  found  in  it  and  it  is  sometimes  ulcerated.] 

The  ileum  joins  the  left  or  inner  side  of  the  caecum  at  a 
very  acute  angle  ;  it  appears  to  perforate  the  latter,  the  pe- 
ritoneum and  external  muscular  fibres  of  the  ileum  being 
continued  into  the  corresponding  parietes  of  the  caecum, 
while  the  circular  fibres  and  mucous  coat  of  the  ileum  pro- 
trude into  the  caecum  to  form  valves,  as  may  be  seen  by 
opening  the  latter  in  a  perpendicular  direction,  on  the  op- 
posite, that  is,  on  the  right  side,  and  washing  out  its  con- ' 
tents  ;  we  then  perceive  the  opening  of  the  ileum,  narrow, 
like  a  transverse  slit,  looking  obliquely  downwards  and 
outwards,  towards  the  right  os  ilii,  and  protected  by  two 
semilunar  folds  of  mucous  membrane,  which  enclose  a  few 
muscular  fibres.  The  inferior  fold,  or  ileo-ccccal  valve,  is  the 
larger,  is  placed  somewhat  vertical,  and  secures  the  ileum 
against  any  matter  re-entering  it  from  the  caecum  ;  the  su- 
perior fold,  or  ileo-colic  valve  is  smaller,  and  placed  rather 
horizontal ;  it  secures  the  ileum  against  regurgitation  from 
the  colon ;  these  semilunar  folds  are  united  to  each  other  at 
their  extremities,  (commissures^  and  from  each  commissure 
a  prominent  fold  is  continued  round  on  the  inner  side  of 
the  caecum ;  these  folds  are  called  the  frsena  or  retinacula 
of  these  valves,  in  consequence  of  which,  and  of  the  com- 
missures, the  distention  of  the  caecum  closes  the  ileo-caecal 
foramen  ;  the  caecum  is  provided  with  the  same  .longitudi- 
nal bands  as  the  colon  ;  it  has  no  valvulae  conniventes. 
The  colon  extends  from  the  caecum  to  the  rectum ;  it  is  di- 
vided into  four  portions,  the  right  or  ascending,  the  middle 
or  transverse  arch,  the  left  or  descending,  and  the  sigmoid 
flexure  ;  there  is,  however,  no  mark  of  distinction  whatever 
as  to  structure  between  these  different  divisions. 

The  ascending  colon  extends  from  the  caecum  to  the  inferior 
15 


170  DUBLIN    DISSECTOR. 

surface  of  the  right  lobe  of  the  liver,  which  it  marks  with 
a  superficial  depression  ;  this  portion  of  the  colon  is  con- 
cave anteriorly,  and  covered  by  the  peritonaeum  and  by  the 
abdominal  muscles ;  it  lies  on  the  right  kidney  ;  the  duo- 
denum is  connected  to  it  internally  ;  the  superior  extremity 
is  generally  tinged  with  bile  from  being  in  contact  with  the 
gall  bladder. 

The  transverse  arch  of  the  colon  extends  tortuously  from 
the  right  hypochondrium,  across  the  inferior  part  of  the 
epigastric  or  the  umbilical  region  into  the  left  hypochon- 
drium ;  it  is  covered  by  the  abdominal  muscles,  and  lies 
anterior  to  the  small  intestines :  on  the  right  side  it  is  con- 
nected to  the  liver,  in  the  middle  to  the  stomach  and  to  the 
great  omentum ;  and  its  left  extremity,  which  is  superior 
and  posterior  to  the  right,  is  attached  to  the  spleen  by  peri- 
toneum ;  the  appendices  epiploicse  are  very  numerous  on 
this  part  of  the  colon. 

The  left  or  descending  colon  extends  from  the  spleen  to  the 
iliac  region,  is  longer  than  the  right,  and  is  connected  to 
the  kidney  and  psoas  by  peritonaeum  and  cellular  mem- 
brane. 

The  sigmoid  flexure  is  connected  so  loosely  in  the  iliac 
fossa,  that  a  great  portion  of  it  often  lies  in  the  pelvis :  this 
part  of  the  colon  is  partially  covered  by  the  small  intes- 
tines, and  connected  to  the  psoas  and  iliac  muscles,  to  the 
ureter  and  spermatic  vessels. 

The  rectum  extends  from  the  sigmoid  flexure  of  the  colon 
to  the  anus ;  it  commences  opposite  the  left  ilio-sacral  arti- 
culation, and  descends  obliquely  towards  the  middle  line  as 
far  as  the  lower  end  of  the  sacrum :  it  then  bends  forwards 
towards  the  perinseum,  and  lastly  turning  downwards,  it 
ends  at  the  anus.  The  rectum  is  connected  posteriorly  to 
the  sacrum  and  coccyx  by  the  meso-rectum  superiorly,  and 
by  vessels  and  nerves  inferiorly ;  anteriorly  the  rectum  is 
connected  to  the  peritonaeum  above,  and  below,  in  the  male 
subject,  to  the  inferior  fundus  of  the  bladder,  the  vesicuke 
seminales,  and  the  prostate  gland:  in  the  female  to  the 
uterus  and  the  vagina :  along  the  sides  of  the  rectum  is  a 
considerable  quantity  of  cellular  tissue,  and  several  vessels, 
particularly  tortuous  veins;  inferiorly  the  levatores  ani 
muscles  cover  the  sides  of  this  intestine,  and  its  lower  ex- 
tremity is  surrounded  by  the  orbicular  and  cutaneous 
sphincters.  The  rectum  is  separated  from  the  bladder  in 
the  male,  and  from  the  uterus  in  the  female  by  the  cul  de 
sac  of  the  peritonaium,  which  may  or  may  not  contain  some 
of  the  small  intestine  according  to  the  state  of  the  pelvic 
viscera  ;  the  rectum,  therefore,  is  only  partially  covered  by 
the  peritonaeum ;  in  the  superior  third  this  membrane  co- 


DUBLIN    DISSECTOR.  171 

vers  the  intestine  all  around,  forming  the  meso-rectum  be- 
hind it ;  in  the  middle  third  it  is  only  connected  to  the  fore 
part,  and  somewhat  to  its  sides  ;  and  to  its  inferior  third  it 
is  wholly  un-attached.  The  rectum  is  also  sacculated  like 
the  colon,  but  the  cells  present  a  different  arrangement  in 
consequence  of  the  peculiar  disposition  of  the  lining  mem- 
brane ;  it  is  found  in  general  much  dilated  about  an  inch 
above  the  anus. 

In  order  to  examine  the  structure  of  the  intestinal  canal, 
let  the  student  remove  the  following  portions  of  intestine, 
including  each  part  between  ligatures,  having  first  distend- 
ed them  with  air  ;  a  portion  of  duodenum,  of  jejunum  near 
its  commencement,  of  ileum  near  its  termination,  of  the 
arch  of  the  colon,  and  of  the  upper  part  of  the  rectum  ; — 
first,  the  duodenum  possesses  three  coats  connected  to  each 
other  by  cellular  membrane  ;  the  peritonseal  or  serous,  the 
muscular  and  the  mucous  ;  the  first  has  been  already  men- 
tioned as  giving  but  a  partial  covering  to  this  intestine ;  the 
muscular  coat  of  the  duodenum  is  formed  of  strong  red 
fibres,  which  take  a  circular  direction  ;  there  are  very  few 
longitudinal  fibres  to  be  observed  along  it,  except  on  the 
superior  transverse  portion :  lay  open  a  part  of  this  intes- 
tine, and  the  internal  mucous  coat  will  be  found,  like  that 
of  the  stomach,  thrown  into  soft  folds  which  lie  nearly  pa- 
rallel to  each  other  in  a  circular  direction ;  these  are  named 
valvulse  conniventes.  Second,  the  jejunum  and  ileum  also 
possess  three  tunics  and  intermediate  cellular  tissue ;  the 
serous  or  peritonseal  coat  almost  perfectly  surrounds  them 
except  the  small  triangular  space  along  the  concave  side 
where  the  vessels  and  nerves  divide,  and  which  space  ad- 
mits of  the  more  easy  distention  of  the  intestine  ;  the  mus- 
cular coat  is  not  so  strong  as  on  the  duodenum,  but  more 
evidently  consists  of  two  sets  of  fibres ;  the  longitudinal  are 
the  most  superficial,  they  are  very  pale  and  indistinct,  ex- 
cept along  the  anterior  or  convex  side  of  the  intestine  ;  the 
circular  fibres  lie  beneath  these ;  they  are  more  distinct 
but  also  very  pale :  no  fibre  passes  perfectly  round  the 
tube.  The  mucous  coat  is  paler  than  in  the  stomach,  and 
is  thrown  into  numerous  folds,  particularly  in  the  jejunum ; 
these  folds  are  smaller  and  less  numerous  in  the  ileum  ;  the 
muscular  coat  in  the  latter  intestine  also  is  paler  and 
weaker  than  in  the  former.  The  folds  of  mucous  mem- 
brane,  called  valvulse  conniventes,  are  larger  in  the  jeju- 
num than  in  the  duodenum  or  ileum ;  in  the  first  they  will 
be  found  to  be  a  quarter  of  an  inch  deep  in  some  situa- 
tions; in  others,  however,  much  less;  they  form  arches 
which  encircle  about  three-fourths  of  the  intestine,  and 
end,  some  in  a  point,  others  are  forked  or  pass  off  oblique- 


172  DUBLIN    DISSECTOR. 

ly  into  adjacent  folds :  these  valves  are  of  use  in  delaying 
the  food  in  its  passage  along  the  canal,  thus  affording  to 
the  absorbents  a  better  opportunity  to  imbibe  all  the  nu- 
tritious matter  of  the  chyle  it  may  contain ;  in  proportion 
also  as  the  intestine  become  distended,  these  valves  be- 
come more  tense,  and  project  into  the  canal,  so  as  to  sepa- 
rate the  food  into  smaller  portions,  and  thus  expose  the  en- 
tire mass  to  the  action  of  the  absorbents  :  on  each  of  these 
valves  are  a  number  of  small  conical  projections  called 
vim :  when  these  are  examined  through  a  magnifying  glass, 
small  pores  are  observable ;  these  are  the  mouths  of  the 
lacteal  or  absorbent  vessels.  Very  small  mucous  glands 
are  attached  to  the  external  surface  of  the  mucous  mem- 
brane of  the  intestine  throughout  its  whole  length  ;  larger 
glands  may  be  noticed  in  different  situations,  some  scatter- 
ed singly,  others  collected  into  clusters ;  the  former,  or  the 
glandule  solitaries  or  Brunneri,  are  most  distinct  in  the 
duodenum ;  the  latter,  or  the  glandula  aggregates  or  Peye- 
riy  are  most  obvious  in  the  ileum,  particularly  near  its  ter-. 
mination.  Third,  the  large  intestine,  in  some  situations,  as 
has  been  already  observed,  is  but  partially  covered  by  peri- 
tonaeum ;  this  membrane  is  more  loosely  connected  to  the 
transverse  arch  of  the  colon  than  it  is  to  the  small  intes- 
tine, and  is  un-attached  along  two  triangular  spaces,  one 
along  the  concave  border  between  the  Iamina3  of  the  meso- 
eolon,  the  other  along  the  convex,  between  the  layers  of  the 
great  omentum ;  this  circumstance  favours  the  distention 
of  the  colon.  The  muscular  coat  of  the  large  intestine  also 
consists  of  longitudinal  and  circular  fibres;  the  former, 
however,  are  collected  into  three  fasciculi,  all  of  which  com- 
mence at  the  vermiform  process,  and  pass  along  the  ca3- 
cum  and  colon  to  the  rectum  :  on  this  intestine  the  fibres 
separate,  increase  in  thickness  and  number,  and  form  a 
more  perfect  tunic ;  near  the  anus  these  fibres  are  con- 
founded with  those  of  the  levator  ani  muscle  of  each  side. 
The  internal  or  mucous  coat  of  the  large  intestine  is  pale, 
and  forms  but  few  and  imperfect  folds ;  in  the  rectum  it 
becomes  more  vascular  and  villous,  and  presents  several 
longitudinal  folds,  as  also  three  or  four  very  remarkable, 
in  a  horizonal  direction,  these  are  so  disposed,  being  at  in- 
tervals and  on  opposite  sides,  as  to  convert  the  canal  into  a 
sort  of  spiral  passage.  As  the  food  is  propelled  along  the 
intestinal  canal,  the  chyle  is  absorbed  by  the  numerous 
lacteal  vessels  to  which  it  becomes  exposed  ;  it  is  also  mixed 
with  a  quantity  of  fluid  (succus  intestinalis)  secreted  by  the 
mucous  glands,  and  by  the  vessels  of  the  mucous  membrane  ; 
in  the  large  intestine  the  food  first  presents  the  feculent 
properties,  and  in  its  passage  along  this  part  of  the  canal, 


DUBLIN    DISSECTOR.  173 

the  absorbent  vessels  continue  to  take  up  any  chyle  that 
may  have  escaped  the  preceding,  as  well  as  the  watery 
parts  of  the  food. 

The  peritonaeum  and  abdominal  viscera  present  many 
morbid  appearances.  Peritonitis  or  inflammation  of  the 
peritonaeum  is  denoted  by  an  increased  and  a  reddish  vas.- 
cularity  of  the  membranes,  a  number  of  small  red  vessels 
can  be  distinctly  seen ;  it  loses  its  transparency,  and  be- 
comes somewhat  thick  and  pulpy ;  the  parietal  and  visce- 
ral layers  are  sometimes  found  agglutinated  by  coagulable 
lymph  which  also  cements  the  several  intestinal  convolu- 
tions, but  sometimes  the  cavity  is  filled  with  serous,  or 
sero-purulent  fluid,  with  shreds  of  lymph :  peritonitis  more 
frequently  ends  in  some  such  eifusion  than  in  the  adhesive 
process,  the  contrary  is  more  frequent  in  pleuritis ;  peri- 
tonitis also  sometimes  exhibits  gangrenous  patches,  but  if  it 
have  been  chronic,  adhesive  bands  and  false  membranes 
are  very  apparent.  In  ascites  or  dropsy  of  this  membrane, 
the  tissue  of  the  latter  appears  sound,  sometimes  remark- 
ably clear  or  pearly ;  in  this  disease,  some  of  the  viscera, 
particularly  the  liver,  are  usually  found  in  an  anormal 
state. 

The  omentum  is  sometimes  the  seat  of  general  induration., 
or  of  particular  tumours,  adipose,  sarcomatous  and  fungoid. 
The  stomach  may  be  the  seat  of  an  acute  inflammation,  or 
gastritis,  the  coats  appear  more  thick  and  vascular  than 
usual,  and  blood  is  sometimes  seen  effused  between  its  tu- 
nics. Ulcers  are  frequently  found  in  the  stomach,  of  an 
oval  or  circular  form,  with  thin  and  firm  edges :  indepen- 
dent of  disease,  the  stomach  not  unfrequently  presents 
considerable  red  patches  on  its  mucous  surface ;  the  coats 
are  also  sometimes  nearly  destroyed  in  some  places,  pre- 
senting a  soft  and  ragged  appearance ;  this  is  caused  by 
the  gastric  fluid  digesting  or  dissolving  the  coats  of  the 
stomach  after  death.  Both  the  cardiac  and  pyloric  ends  of 
the  stomach  are  the  frequent  seat  of  cancer ;  this  principal- 
ly involves  the  mucous  and  muscular  tissues,  on  the  for- 
mer, large  fungoid  masses  are  thrown  out  which  more  or 
less  constrict  or  obstruct  the  orifices  of  the  organ,  and  im- 
pair its  functions. 

The  intestinal  tube  is  subject  to  numerous  diseases,  in 
most  of  which  the  effects  of  inflammation  are  more  or  less 
visible :  inflammation  or  enteritis  is  denoted  by  increased 
vascularity  of  the  mucous  surface  and  thickening  of  the 
tunics,  in  some  cases  the  peritonaeum  is  also  engaged  ;  the 
colour  of  the  intestine  is  a  deep  or  dark  red ;  acute  inflam- 
mation sometimes  ends  in  gangrene  and  effusion,  sometimes 
in  ulceration.  The  whole  of  the  intestinal  surface  may  bo 
15* 


174  DUBLIN    DISSECTOR. 

the  seat  of  ulceration ;  in  the  small  intestines,  the  ulcers 
are  generally  small,  and  are  often  found  in  the  situation  of 
the  mucous  glands ;  in  the  large  intestines  the  ulceration  is 
usually  in  larger  patches,  and  in  cases  of  dysentery  is  of- 
ten very  extensive.  The  intestinal  tunics  are  occasionally 
the  seat  of  malignant  tubercle,  which  may  obstruct  the 
course  of  the  contents  of  the  tube ;  of  all  parts  of  the  in- 
testinal canal  the  rectum  is  most  frequently  the  seat  of 
scirrhus  and  its  consequences. 

[The  gastro- enteric  mucous  membrane,  is  of  much  importance  in 
its  pathology,  and  it  is  therefore  necessary  to  understand  fully  its 
physiological  state,  as  to  thickness,  consistence  and  color;  the  two 
former  as  a  general  rule  are  in  direct  ratio,  but  differ  much  in  dif. 
ferent  situations.  The  color  also  varies  much  in  a  state  of  health,  as 
well  as  in  disease.  The  entire  thickness  of  the  intestinal  walls,  is  less 
in  the  lower  part  of  the  jejunum,  the  ileum,  and  the  colon,  than  in 
the  stomach,  duodenum,  upper  part  of  the  ileum  and  rectum.  The 
thickness  of  the  mucous  membrane  is  greatest  in  the  duodenum,  and 
next  in  some  parts  of  the  stomach  and  rectum ;  in  the  small  intestines 
its  thickness  gradually  diminishes,  from  the  duodenum  to  the  ileum, 
in  the  lower  part  of  which  it  becomes  very  thin.  In  the  large  intes. 
tine,  the  mucous  membrane  is  thin  from  its  commencement  until  we 
reach  the  middle  of  the  transverse  portion  of  the  arch,  from  which 
point  it  increases  in  thickness  as  far  as  the  sigmoid  flexure,  where  it 
is  again  thin,  and  lastly  in  the  rectum,  it  is  again  nearly  as  thick  as 
in  the  duodenum.  The  mucous  coat  of  the  stomach  about  the  oeso- 
phagus, and  in  the  great  cul  de  sac,  is  thin,  soft,  and  can  only  be  sepa- 
rated in  shreds,  whereas  towards  the  right  side,  and  the  pyloric  ex 
tremity,  it  is  from  two  to  three  times  as  thick,  more  resisting,  and 
can  be  separated  for  a  much  greater  extent :  the  gastro  enteric  mu- 
cous coat  has  no  epithelium,  this  ending  above  at  the  termination  of 
the  oesophagus,  and  being  again  found  below,  near  the  verge  of  the 
anus.  As  already  stated  it  is  a  general  rule,  that  the  consistence  of 
this  membrane  is  in  direct  ratio  to  its  thickness ;  this  however  is  not 
true  of  the  duodenum,  where  it  is  thickest,  yet  its  tenacity  is  so  slight 
that  it  can  only  be  raised  in  fragments.  The  consistence  is  greater 
near  the  pyloric  than  the  cesophageal  portion  of  the  stomach ;  in  the 
lower  part  of  the  jejunum  and  the  ileum  its  consistence  is  greater  than 
in  the  duodenum,  while  in  the  large  intestine  it  is  again  less.  The 
consistence  throughout  is  greater  in  the  adult,  than  in  the  fetus. 
The  color  of  this  membrane  varies  at  different  periods  of  life,  and  ap- 
pears to  be  deep,  in  proportion  to  the  activity  of  the  arterial  develop- 
ment and  circulation ;  accordingly  in  the  foetus  and  child,  it  is  of  a 
deep  rose  color,  in  the  adult  it  is  much  whiter,  and  in  the  old  subject 
it  is  of  a  greyish,  or  ash  color ;  again  the  color  differs  with  the  state 
of  the  system,  being  deeper  in  those  in  strong  health,  and  of  the  san- 
guine temperament,  than  in  others  in  whom  the  reverse  obtains. 

The  color  also  is  affected  by  the  process  of  digestion,  by  which  it 
is  changed  from  a  pale  pink  or  almost  white,  to  a  deep  red  almost 
vermilion  hue,  the  intensity  however  depending  upon  the  stimulating 
quality  of  the  food  used ;  this  change  of  color  seems  to  affect  the 


DUBLIN    DISSECTOR.  175 

stomach,  duodenum,  and  upper  part  of  the  jejunum,  while  the  other 
portions  of  the  canal  are  but  little  altered.  The  color  of  the  gastro- 
enteric  mucous  membrane,  depends  also  upon  the  kind  of  death.  In 
those  who  have  died  of  long  continued  diseases,  it  is  apt  to  be  of  a 
pale  blanched  appearance ;  in  persons  who  die  suddenly  and  from 
violence,  as  hanging,  drowning  &c.,  it  is  found  of  a  deep  red  color. 
Lastly  the  color  is  affected  by  different  substances  taken  into  the 
stomach,  as  infusion  of  logwood,  spirits  of  lavender,  nitrate  of  silver 
&c.,  the  two  former  cause  a  deep  red  color,  the  latter  a  greyish  or 
slate  color. 

There  is  also  a  post  mortem  redness,  of  the  membrane,  depending, 
upon  the  accumulation  of  blood  at  the  more  dependent  parts.  All 
these  facts  are  of  importance  in  legal  medicine.  The  submucous 
cellular  tissue  is  so  distinct  and  developed,  that  it  deserves  to  be  con- 
sidered  as  a  proper  tunic,  the  third  coat  of  the  stomach  and  intes- 
tines ;  it  gives  great  strength  and  resistance  to  the  organs,  and  serves 
as  a  skeleton  for  the  attachment  of  the  muscular  fibres ;  this  coat  is 
very  distinct  in  the  purely  carnivorous  animals,  the  vessels  ramify 
upon  this  tunic,  before  being  distributed  to  the  mucous  membrane, 
and  the  muciparous  glands  are  imbedded  in  it,  although  they  open 
upon  the  surface  of  the  lining  membrane.  These  follicles  are  more 
fully  developed  in  children  than  in  adults,  and  in  preparing  them  may 
be  rendered  more  distinct  by  the  application  of  warm  vinegar.  The 
single  follicles  are  larger  in  the  duodenum,  than  in  the  stomach,  in 
the  rest  of  the  small  intestines,  they  are  also  larger,  than  in  the 
stomach,  but  smaller  than  in  the  duodenum,  or  large  intestines.  The 
glandules  agminate  of  Peyer,  or  elliptical  plates  as  they  are  called 
from  their  form,  are  almost  confined  to  the  lower  half  of  the  ileum, 
and  vary  in  number  from  eighteen  to  twenty-five  ;  they  also  vary  in 
size,  being  from  half  an  inch,  and  even  a  fourth,  to  two  inches  in 
length,  and  from  two  or  three  to  ten  lines  in  breadth,  they  are  always 
found  along  the  convex  edge  of  the  intestine  opposite  the  attach- 
ment of  the  mesentery,  and  are  entirely  wanting  in  the  large  intes- 
tine. These  organs  are  supposed  to  be  physiologically  different  from 
the  solitary  follicles,  because  they  present  certain  pathological  differ- 
ences. The  plates  are  found  enlarged,  prominent,  and  even  ulcerated 
in  phthisis,  typhus  fever,  and  scarlatina  maligna.  The  intestines 
may  communicate  with  the  cavity  of  the  peritoneum,  either  by  per- 
foration or  laceration,  the  former  of  which  is  the  result  of  ulceration 
of  the  coats,  the  latter  of  external  violence,  and  may  occur  without 
any  external  marks  upon  the  abdomen  :  the  parts  most  liable  to  la- 
ceration, are  the  jejunum  and  upper  part  of  the  ileum.  Any  of  the 
viscera  of  the  abdomen  may  be  involved  in  a  hernial  tumour,  but 
most  commonly  the  omentum,  or  the  lower  part  of  the  small  intestine 
is  protruded.  The  small  and  large  intestines  are  both  the  seat  of  in- 
tussusception, but  the  ileum  is  most  liable  to  it ;  its  extent  varies  from 
an  inch  or  two  to  even  three  feet,  and  sometimes  the  invaginated  por- 
tion sloughs  off  and  is  discharged.  There  is  one  form  of  this  affec- 
tion, which  appears  to  occur  in  articulo  mortis,  presenting  no  signs 
of  inflammation  ;  there  may  be  from  one  to  twelve  of  these  displace- 
ments in  the  same  subject,  and  it  may  occur  in  either  direction. 
Earthy  concretions,  are  sometimes  found  in  the  alimentary  canal,  of 


176  DUBLIN    DISSECTOR. 

the  human  subject  as  well  as  of  inferior  animals ;  they  vary  in  size 
from  that  of  a  pea  to  that  of  an  orange,  and  one  case  is  recorded  in 
which  the  body  weighed  four  pounds  ;  the  number  also  varies,  there 
being  generally  but  two  or  three,  but  sometimes  ten  or  fifteen,  they 
usually  exhibit  a  central  nucleus.  In  the  college  museum  there  are 
two  specimens  from  the  inferior  animals,  (presented  by  Dr.  Sabine 
of  this  city,  who  has  a  very  choice  private  collection  of  Morbid  Ana. 
tomy  and  Natural  History,)  one  of  which  taken  from  the  stomach  of 
a  liorse  has  for  its  nucleus,  what  appears  to  be  a  bit  of  corn  cob,  its 
diameter  is  about  four  inches,  it  is  formed  of  concentric  laminae,  looks 
like  marble  and  receives  a  high  polish.  The  hair  balls  found  in  the 
stomach  of  the  ox,  appear  to  be  formed  by  an  accumulation  of  hair 
coated  over  with  numerous  layers  of  concrete  mucus,  which  form  a 
complete  capsule. 

In  post  mortem  examinations  of  the  abdomen,  some  portion  of  the 
intestine,  is  often  seen  very  much  contracted,  so  as  almost  to  oblite- 
rate its  cavity  and  yet  no  evidences  of  disease  are  present,  this  occurs 
in  coils  of  the  small  intestine  but  more  often  in  the  large,  in  the  fol- 
lowing order  as  to  frequency,  the  left  part  of  the  transverse  portion 
of  the  arch  of  the  colon,  the  descending  portion,  the  sigmoid  flexure, 
and  the  upper  part  of  the  rectum.  This  condition  appears  to  depend 
upon  the  close  contraction  of  the  muscular  fibres  upon  the  empty  in- 
testine. Hemorrhoids,  prolapsus  ani,  fissura  ani,  and  fistula  in  ano, 
are  all  diseases  occuring  in  the  lower  part  of  the  rectum,  and  about 
the  anus.  Intestinal  worms,  of  different  kinds,  may  be  found  in  the 
alimentary  tube,  at  almost  any  point  between  the  mouth  and  the 
anus.  The  existence  of  worms  in  the  cavity  of  the  peritonaeum  with- 
out perforation  or  laceration,  was  demonstrated  to  me  a  year  since, 
in  the  post  mortem  examination  of  a  horse,  which  died  of  acute 
pleuritis.  These  worms  were  found  principally  on  the  peritoneal 
covering  of  the  liver,  but  were  moving  freely  in  the  cavity  ;  there- 
were  from  ten  to  fifteen  of  them  varying  in  length  from  two  and  a 
half  or  three,  to  six  inches,  and  from  one  to  two  lines  in  diameter. 
There  was  no  evidence  of  disease  about  the  peritoneum;  lam  not 
aware  that  any  thing  of  this  kind  has  been  seen  in  the  human  sub- 
ject. Anomalies  not  unfrequently  occur,  in  the  development  of  the 
alimentary  canal,  and  many  of  them  are  analogous,  to  the  natural 
conformation  of  inferior  animals.  The  large  intestines  are  sometimes 
entirely  wanting,  the  ileum  ending  in  a  blind  cul  de  sac ;  sometimes 
the  rectum  only  is  wanting,  at  others,  the  anus  is  simply  imperforate. 
The  rectum  sometimes  terminates  in  the  bladder,  in  the  vagina  or 
in  the  urethra ;  in  a  case  of  the  latter  kind  which  occured  in  a  male 
child,  the  subject  lived  one  year,  and  then  died  from  inflammation 
arising  from  neglect  of  the  parts.  The  vermiform  appendix  is  some- 
times entirely  wanting,  and  not  unfrequently  the  small  intestines  pre- 
sent processes  or  blind  canals,  from  one  to  three  or  four  inches  in 
length.] 

The  glandular  viscera  of  the  abdomen  which  are  subser- 
vient to  digestion  are  the  liver,  spleen,  and  pancreas. 

The  liver  is  the  largest  secreting  gland  in  the  body ;  it 
fills  the  right  hypochondrium,  extends  though  the  anterior 


DUBLIN    DISSECTOR.  177 

part  of  the  epigastric  region  into  the  left  hypochondrium 
as  far  as  the  cardiac  orifice  of  the  stomach,  beyond  which, 
however,  it  frequently  extends,  even  to  the  spleen  ;  it  is  sit- 
uated below  the  diaphragm,  and  above  the  right  kidney, 
the  stomach,  duodenum,  and  lesser  omentum ;  it  is  support- 
ed in  this  situation  by  several  folds  of  peritoneum,  termed 
ligaments  of  the  liver,  viz.  the  falciform,  round,  right,  left 
and  coronary  ;  these  connect  it  to  the  diaphragm  and  ab- 
dominal muscles,  and  the  lesser  omentum  attaches  it  to  the 
stomach  and  duodenum. 

The  suspensory  or  falciform  ligament  is  a  fold  of  perito- 
neum attached  anteriorly  by  its  convex  border  to  the  linea 
alba,  to  the  rectus  muscle  of  the  right  side,  and  to  the  dia- 
phragm; it  passes  obliquely  backwards  and  to  the  right 
side,  and  is  attached  by  its  posterior  or  concave  edge  to  the 
upper  or  convex  surface  of  the  liver,  on  which  its  laminae 
separate,  and  expand  over  each  side  of  this  organ ;  en- 
closed in  the  inferior  edge  of  this  fold  is  the  obliterated 
umbilical  vein,  which  substance  in  the  adult  is  named  the 
ligamentum  teres :  this  which  is  enumerated  as  the  second 
ligament  of  the  liver,  ascends  from  the  umbilicus,  obliquely 
backwards,  and  to  the  right  side,  and  is  inserted  into  a 
notch  in  the  thin  or  anterior  edge  of  the  liver,  which  notch 
is  the  commencement  of  the  umbilical  or  horizontal  fissure 
of  the  liver.  The  right  and  left  lateral  ligaments  are  trian- 
gular folds,  connecting  the  right  and  left  lobes  of  the  liver 
to  the  diaphragm  :  the  left  lateral  ligament  lies  anterior  to 
the  cardiac  orifice  of  the  stomach :  the  right  lateral  liga- 
ment is  directly  above  the  right  kidney.  The  coronary  lig- 
ament is  situated  at  the  upper  extremity  of  the  falciform 
process,  and  consists  of  two  laminse  of  peritoneum,  which 
separate  from  each  other,  and  connect  the  superior  thick 
edge  of  the  liver  to  the  diaphragm  ;  between  the  laminse  of 
this  process  the  liver  is  deprived  of  a  serous  covering,  and 
is  in  contact  with  the  diaphragm ;  this  space  lies  anterior 
to  the  inferior  vena  cava.  The  liver  is  of  an  irregular 
form ;  it  is  longer  transversely  than  from  before  back- 
wards ;  its  posterior  edge  is  very  thick,  and  in  contact  with 
the  diaphragm ;  its  anterior  edge  is  thin,  convex,  and  on  a 
level  with  the  edge  of  the  right  hypochondrium,  and  with 
the  lower  part  of  the  epigastric  region ;  two  notches  may 
be  observed  in  this  edge ;  one  below  the  falciform  ligament, 
into  which  the  round  ligament  or  obliterated  umbilical  vein 
enters,  the  other  corresponds  to  the  gall  bladder. 

[The  size  and  weight  of  the  liver  are  very  much  affected  by  dis- 
ease, and  by  the  state  of  its  own  circulation,  which  also  affects  its 
color.  In  a  state  of  health  its  average  weight  is  from  three  and  a 
quarter, to  four  and  a  quarter  pounds :  the  transverse  diameter  is  from 


178  DUBLIN    DISSECTOR. 

fen  to  twelve  inches,  the  antero-posterior  from  six  to  seven,  and  the 
thickness  at  the  centre  and  posterior  edge  from  two  and  a  half  to  three 
and  a  half.  The  color  of  the  organ  varies  with  the  amount  of  blood  in  it, 
thus  in  the  foetus  the  organ  is  very  vascular  and  of  a  florid  red,  in  the 
adult  it  is  of  a  reddish  brown  color,  with  blue  or  black  spots,  on  the 
anterior  margin  and  inferior  surface  ;  in  persons  who  have  been  hung, 
it  is  said  to  be  of  a  deep  pink,  or  even  purple,  and  in  simple  conges- 
tion it  is  of  a  florid  red.  The  volume  of  the  organ  varies  with  its 
own  circulation,  thus  it  is  very  large  if  there  be  an  obstruction  to  the 
return  of  the  blood  to  the  heart.  It  is  also  proportionably  very  much 
greater  in  the  foetus  and  new  born  infant,  than  in  the  child  or  adult ; 
thus  it  is  said  that  in  the  foetus  of  three  weeks,  the  weight  of  the  liver 
is  equal  to  half  that  of  the  whole  body,  at  the  full  term  to  one  eigh- 
teenth, and  in  the  adult,  to  one  thirty-sixth.] 

The  superior  or  anterior  surface  is  smooth  and  convex, 
and  divided  by  the  suspensory  ligament  into  a  right  and 
left  portion,  and  is  contiguous  to  the  diaphragm.  The 
inferior  surface  is  very  irregular,  marked  by  several  pro- 
jections and  depressions ;  the  former  are  called  lobes,  and 
are  five  in  number,  viz.  first,  the  great  or  right  lobe ;  second, 
the  left,  separated  from  the  former  by  the  horizontal  fis- 
sure ;  third,  the  Spigelian  or  middle  lobe ;  this  is  situated  be- 
hind the  lesser  omentum,  and  above  and  behind  the  trans- 
verse fissure,  and  between  the  oesophagus  and  the  cava  ;  it 
is  connected  to  the  right  lobe  by  two  roots ;  one  is  thin  and 
placed  vertically  between  the  fissure  for  the  vena  cava  and 
that  for  the  ductus  venosus ;  the  other  is  thick  and  placed 
transversely,  and  is  called  lobulus  caudatus,  or  the  fourth 
lobe  of  the  liver ;  the  lobulus  caudatus  is  immediately  be- 
hind the  transverse  fissure,  and  extends  from  the  Spigelian, 
along  the  right  lobe  between  the  depressions  marked  by 
the  colon  and  right  kidney.  Fifth,  the  lobulus  quadratus  or 
anonymus,  is  at  the  anterior  part  of  the  right  lobe,  in  front 
of  the  transverse  fissure,  and  between  the  gall  bladder  and 
horizontal  fissure. 

The  principal  depressions  or  fissures  on  the  inferior 
surface  of  the  liver  are  the  following  :  first  the  transverse 
fissure  which  is  situated  between  the  lobulus  quadratus 
and  caudatus,  and  extends  from  the  horizontal  fissure 
transversely  to  the  right ;  the  vessels  and  nerves  of  the 
liver  enter  the  gland  in  this  fissure  ;  second  the  horizontal 
fissure  extends  from  the  notch  in  the  anterior  edge  of  the 
liver,  backwards  and  upwards  between  the  right  and  left 
lobes ;  the  anterior  part  of  this  fissure  contains  the  ob- 
literated umbilical  vein,  the  posterior  part  the  obliterated 
ductus  venosus ;  third,  the  fissure  for  the  vena  cava  is  between 
the  lobulus  Spigelii  and  the  right  lobe ;  this,  at  the  ante- 
rior part  of  the  horizontal  fissure,  is  frequently  like  a 


DUBLIN    DISSECTOR.  179 

foramen  in  the  liver,  being  surrounded  by  the  substance 
of  the  gland :  fourth,  the  depression  for  the  gall  bladder  is  on 
the  inferior  surface  of  the  right  lobe,  and  to  the  right  side 
of  the  lobulus  quadratus ;  the  substance  of  the  liver  is 
sometimes  deficient  over  this  bag ;  fifth  and  sixth,  super- 
ficial depressions  on  the  under  surface  of  the  right  lobe ; 
the  anterior  corresponds  to  the  colon,  the  posterior  to  the 
right  kidney  and  its  capsule ;  these  depressions  are  indis- 
tinctly marked  in  some  subjects ;  they  are  separated  from 
each  other  by  the  extremity  of  the  lobulus  caudatus ; 
seventh,  a  superficial  depression  on  the  under  surface  of 
the  left  lobe,  corresponding  to  the  anterior  surface  of  the 
stomach ;  eighth,  a  broad  notch  in  the  posterior  edge  of 
the  liver,  corresponding  to  the  spine  and  to  the  right  crus 
of  the  diaphragm ;  the  venae  cavse  hepaticse  leave  the  liver 
in  this  situation.  The  liver  is  of  a  peculiar  brown  colour, 
interspersed  with  yellow;  in  some  subjects  it  is  much 
darker  than  in  others :  in  the  very  young  it  is  red  and  soft, 
and  in  the  old  it  is  generally  pale  and  yellow,  and  often 
hard  and  brittle ;  it  has  two  coats,  a  serous  and  fibrous ; 
the  serous  or  peritonseal  tunic  covers  the  whole  surface  of 
the  liver,  except  in  those  situations  where  the  vessels, 
either  pervious  or  obliterated,  are  situated,  and  between 
the  laminse  of  the  corronary  ligament,  also  in  the  depres- 
sion in  which  the  gall  bladder  is  lodged.  The  second,  or 
fibrous  coat,  is  the  immediate  capsule  to  the  gland ;  it  is 
thin,  little  more  than  condensed  cellular  membrane ;  it  is 
most  distinct  and  strong  where  the  serous  coat  is  deficient ; 
it  covers  the  whole  surface  of  the  liver,  and  adheres  to  it 
by  innumerable  shreds  or  processes,  which  pass  into  its 
substance;  it  also  accompanies  the  three  vessels  of  the 
liver  which  enter  or  leave  the  transverse  fissure,  and  forms 
a  capsule  or  sheath  around  their  ramifications  throughout 
the  entire  organ;  this  sheath  receives  the  name  of  the 
capsule  of  Glisson;  it  surrounds  the  vessels  very  loosely, 
and  also  encloses  loose  cellular  tissue ;  hence  it  is,  that  if 
these  vessels  be  divided  by  a  perpendicular  incision  through 
the  liver,  they  will  be  found  to  collapse  and  recede ;  where- 
as, if  the  venae  cavse  hepaticse,  which  run  from  the  thin 
towards  the  thick  edge  of  the  liver,  be  divided  by  a  trans- 
verse incision  through  the  liver,  they  will  not  recede  or 
collapse,  but  remain  perfectly  open,  in  consequence  of  the 
absence  of  this  sheath,  and  of  their  close  adhesion  to  the 
substance  of  the  gland.  The  structure  of  the  liver  con- 
sists of  numerous  small  granulations  of  a  brown  and  yel- 
low colour,  connected  together  by  the  branches  of  the  he- 
patic arteries,  veins,  and  ducts ;  these  grains  are  called 
acini  of  the  liver,  in  each  of  them  a  branch  of  the  hepatic 


180  DUBLIN    DISSECTOR. 

artery  and  vena  portarum  terminate,  and  out  of  each 
proceed  a  branch  of  the  hepatic  veins  and  ducts.  Through 
the  liver,  therefore,  four  sets  of  vessels  ramify,  in  addition 
to  numerous  lymphatics,  viz.  the  branches  of  the  hepatic 
arteries,  vense  portarum,  hepatic  ducts  and  hepatic  veins  : 
the  venas  portarum  are  supposed  to  be  the  vessels  from 
which  the  bile  is  secreted ;  the  hepatic  arteries  nourish 
the  substance  of  the  liver  ;  the  hepatic  ducts  carry  the  bile 
from  this  organ,  and  the  vense  cavas  hepatica3  return  the 
blood  which  has  circulated  through  the  liver,  to  the  inferior 
vena  cava,  just  as  this  vessel  is  passing  through  the  dia- 
phragm. The  vena  cav&  hepatica,  three  or  four  in  number, 
are  seen  escaping  from  the  liver  at  the  superior  thick  edge, 
behind  the  coronary  ligament,  and  immediately  joining  the 
inferior  or  ascending  vena  cava.  The  three  other  vessels 
of  the  liver  may  be  seen  between  the  layers  of  the  lesser 
omentum,  the  artery  lying  to  the  left  side,  the  biliary  duct 
to  the  right,  the  vena  portarum  behind  and  between  both ; 
the  artery  and  vein  descend  obliquely  inwards  towards  the 
spine,  behind  the  pancreas.  The  hepatic  artery  is  a  branch 
of  the  coeliac  axis,  and  the  vena  portarum  commences  in 
front  of  the  last  dorsal  vertebra,  and  behind  the  pancreas, 
from  the  confluence  of  the  splenic  and  mesenteric  veins 
The  right  and  left  hepatic  ducts,  on  clearing  the  transverse 
fissure,  unite  and  form  the  hepatic  duct,  which  descends  for 
about  one  inch  and  a  half  along  the  right  side  of  the  les- 
ser omentum,  and  is  then  joined  by  the  cystic  duct,  from 
the  gall  bladder :  the  union  of  these  forms  the  ductus  corn- 
munis  choledochus ;  this  vessel,  about  three  inches  long, 
descends  vertically  behind  the  pylorus,  the  upper  part  of 
the  duodenum  arid  the  pancreas,  and  is  imbedded  in  the 
substance  of  the  latter,  about,  the  middle  of  the  internal  or 
concave  side  of  the  middle  division  of  the  duodenum,  this 
duct  perforates  the  coats  of  this  intestine  in  a  very  oblique 
direction,  and  opens  on  a  small  papilla  internally,  opposite 
the  lower  angle  of  the  duodenum :  as  the  ductus  choledo- 
chus is  about  to  perforate  the  duodenum,  it  is  in  general 
joined  by  the  duct  from  the  pancreas. 

No  viscus  in  the  abdomen  presents  such  frequent  and  varied 
morbid  appearances  as  the  liver ;  acute  inflammation,  or 
hepatitis  is  but  rarely  met  in  the  dead  body  ;  it  is  denoted 
by  a  deep  red  or  purple  colour,  a  firm,  heavy  feel,  and  in 
the  opinion  of  some,  by  an  increase  of  size ;  the  investing 
capsule  is  easily  detached,  and  the  parenchyma  appears 
very  granular  and  vascular:  inflammation  may  end  in 
suppuration,  which,  in  general,  is  collected  into  a  very 
large  abscess,  the  contents  of  which  may  have  been  dis- 
charged into  the  colon,  the  stomach,  or  some  of  the  intes- 


DUBLIN    DISSECTOR.  181 

tines  ;  abscess  of  the  liver  also  sometimes  points  external, 
ly,  and  in  some  rare  cases,  opens  into  the  cavity  of  the 
pleura,  or  into  some  of  the  bronchial  tubes.  The  liver  is 
the  seat  of  different  sorts  of  tubercles,  viz.  small  and  dif- 
fused, large  and  circumscribed,  scrofulous,  scirrhous,  fun- 
goid, hydatid,  melanotic,  &c. :  hydatid  cysts  containing 
several  small  hydatids  are  not  uncommon  in  this  organ. 

[The  liver  is  also  liable  to  hypertrophy  and  atrophy,  which  are 
usually  connected,  with  either  an  indurated  or  a  softened  state  of 
the  organ  ;  it  is  also  the  seat  of  a  fatty  degeneration,  and  occasionally 
the  worm  called  liver  fluke  is  found  in  it,  but  much  more  frequently 
in  inferior  animals  ;  it  is  also  the  seat  of  scirrhosis,  in  which  disease 
it  presents  a  tuberculated  or  nutmeg  like  appearance  ;  cartilaginous 
and  osseous  depositions  are  also  found.] 

The  gall  bladder  is  situated  in  the  right  hypochondrium 
in  a  depression  on  the  inferior  surface  of  the  right  lobe  of 
the  liver :  this  membranous  sac  is  of  a  pyriform  figure ; 
the  large  extremity  or  fundus  being  directed  forwards  and 
downwards ;  in  some  persons  it  projects  below  the  liver 
against  the  abdominal  muscles ;  it  is  generally  contiguous 
to  the  pylorus  and  to  the  colon ;  the  smaller  extremity  or 
neck  of  the  gall  bladder  is  directed  upwards,  backwards, 
and  inwards,  is  a  little  convoluted,  and  ends  in  the  cystic 
duct,  which  is  about  an  inch  and  a  half  long :  this  duct 
bends  downwards  and  inwards,  and  joins  the  hepatic  duct 
at  an  acute  angle,  the  union  of  which  forms,  as  was  before 
mentioned,  the  ductus  choledochus.  The  gall  bladder  is 
closely  united  to  the  liver  by  the  peritonseum,  which  pass- 
es over  it;  also  by  cellular  membrane  and  small  blood- 
vessels ;  it  is  composed  of  a  partial  serous  and  a  perfect 
cellular  coat,  and  is  lined  by  a  mucous  membrane;  the 
latter  has  a  peculiar  honey-comb-like  appearance,  and  in 
the  duct  is  disposed  in  a  spiral  lamina  ;  there  is  no  appear- 
ance of  a  muscular  coat.  This  viscus  serves  as  a  reservoir 
for  the  bile,  when  this  fluid  is  not  required  in  the  intestinal 
canal.  The  bile  is  secreted  in  the  liver,  and  flows  down 
the  hepatic  duct,  and  if  not  required  in  the  duodenum,  or  if 
obstructed  in  the  ductus  choledochus,  it  passes  into  the 
cystic  duct  to  the  gall  bladder,  where  it  resides  a  longer  or 
shorter  time,  during  which  period  its  watery  part  is  absorb- 
ed ;  at  the  end  of  some  time,  when  the  bile  is  required  to 
assist  in  digestion,  it  is  forced  out  of  the  gall  bladder,  and 
then  flows  again  along  the  same  cystic  duct  to  the  ductus 
choledochus,  and  so  to  the  duodenum.  The  bile  is  not 
secreted  in  the  gall  bladder,  nor  can  it  possibly  enter  or 
leave  this  viscus  by  any  other  channel  than  through  the 
cystic  duct. 

The  morbid  appearances  observed  in  the  gall  bladder  are, 


T82  DUBLIN    DISSECTOR. 

great  distention,  in  consequence  of  obstructed  ductus  cho- 
ledochus,  or  almost  total  obliteration  of  its  cavity  in  con- 
sequence of  obstructed  cystic  duct.  This  viscus  also  fre- 
quently contains  biliary  calculi ;  when  there  is  but  one 
calculus  it  is  usually  large  and  of  an  oval  form,  and  either 
fills  the  cavity,  or  partly  obstructs  the  duct ;  there  are 
frequently  several  calculi  present,  in  this  case  they  present 
every  variety  of  form  and  size,  as  also  several  smooth  sides 
and  angles,  the  probable  effect  of  rubbing  against  each 
other. 

The  spleen  is  situated  in  the  left  hypochondrium,  between 
the  stomach  and  ribs,  beneath  the  diaphragm,  and  above 
the  kidney  and  the  colon  ;  it  is  in  contact  with  and  connect- 
ed to  the  diaphragm  by  the  peritonaeum,  also  to  the  stomach 
and  pancreas  by  vessels  and  by  the  peritonaeum.  The  spleen 
is  somewhat  ovaf;  convex  towards  the  ribs,  and  concave 
towards  the  stomach  ;  on  the  latter  surface  there  are  sever- 
al holes,  and  about  the  centre  of  it  a  depression  or  fissure 
for  the  entrance  and  exit  of  blood  vessels ;  all  this  surface, 
however,  is  not  concave,  the  part  anterior"  to  the  vessels 
only  being  so,  while  the  part  posterior  to  them  is  convex ; 
the  colour  of  the  spleen  is  somewhat  purple  or  livid;  it  is 
covered  by  peritonaeum,  and  beneath  this  by  a  fibrous  cap- 
sule, which  invests  its  entire  surface,  and  also  passes  into 
its  substance  along  with  the  blood-vessels,  and  assists  in 
forming  the  cells  of  which  this  organ  is  composed  :  these 
cells  are  found  to  contain  a  quantity  of  blood,  partly  co- 
agulated ;  also  a  number  of  small  grains,  which  may  be 
separated  by  maceration,  but  the  nature  of  which  is  not 
well  understood ;  the  spleen  has  no  excretory  duct.  The 
exact  use  or  function  of  this  viscus  is  not  yet  ascertained  ; 
sometimes  two  or  more  small  bodies,  of  the  same  colour 
and  structure  as  the  spleen,  are  found  in  its  vicinity,  be- 
tween the  laminse  of  the  omentum. 

[The  color  of  the  spleen  varies  from  a  pale  grey  to  a  dark  brown, 
or  deep  blue,  it  is  influenced  by  disease,  age,  and  the  kind  of  death. 
In  the  recent  subject  it  is  of  a  light  blueish  shade,  which  soon  changes 
to  a  deep  purple,  especially  on  exposure  to  the  air.  Its  weight  is 
variable  even  in  a  state  of  health,  rarely  exceeding  eight  ounces,  it  is 
sometimes  as  much  as  fourteen,  and  then  again  as  low  as  two.  It 
also  varies  much  in  volume,  in  the  majority  of  cases  however,  its 
length  is  from  four  and  a  half  to  five  inches,  its  width  from  two  and 
a  half  to  three,  and  its  thickness  one  and  a  half ;  its  volume  is  pro- 
portionably  greater  in  man  than  in  other  animals,  and  in  the  adult, 
than  in  the  foetus,  its  volume  seems  also  to  depend  upoiv  its  own  cir- 
culation in  connection  with  the  process  of  digestion.  Supernumerary 
spleens  sometimes  exist,  but  there  are  rarely  more  than  one  or  two 
of  them ;  still  cases  are  reported  in  which  there  have  been  seven,  ten, 
and  even  twenty ;  they  are  found  in  the  oment'tra  gastro-flplenicum, 


DUBLIN    DISSECTOR.  183 

and  are  about  the  size  of  a  nutmeg,  many  animals  have  more  than 
one  spleen.] 

The  spleen  is  not  often  found  diseased ;  the  greatest  possi- 
ble variety  as  to  size  and  consistence  is  observed,  without 
any  morbid  change  ;  in  some  cases  it  is  so  soft  as  to  break 
under  the  slightest  pressure  :  its  coats  are  subject  to  thick- 
ening and  induration,  cartilaginous  and  even  bony  tuber- 
cles or  patches  are  very  common  occurrences  in  its  fibrous 
capsule. 

The  pancreas  lies  behind  the  stomach,  and  may  be  exposed 
by  dividing  the  great  omentum  below  the  stomach,  and  rais- 
ing the  latter  organ  towards  the  thorax.  This  conglomerate 
gland  is  of  great  length,  about  seven  inches  long,  and  about 
an  inch  and  a  half  broad. 

[And  its  medium  thickness  is  six  lines,  it  is  however  thicker  at  its 
right  than  its  left  extremity.  Its  volume  is  proportionally  greater  in 
the  foetus  and  child  than  in  the  adult.  Its  color  varies  with  age,  in 
children,  it  is  of  a  rosy  tint,  in  adults  lighter,  and  in  old  age  of  a  pale 
yellowish  hue.l 

It  extends  from  the  lower  part  of  the  left  hypochondriac 
and  epigastric  regions,  obliquely  downwards  and  forwards 
into  the  umbilical  region,  where  it  is  surrounded  by  the  duo- 
denum ;  it  is  covered  by  the  stomach  and  the  ascending 
layer  of  the  meso-colon;  it  lies  anterior  to  the  left  cms  of 
the  diaphragm,  the  vena  portarum,  and  the  aorta,  and  over- 
laps the  concave  border  of  ,tke  duodenum,  to  which  it  ad- 
heres very  closely.  The  splenic  or  left  extremity  (its  tail) 
is  small,  compared  with  the  right,  which  is  broad  and  flat, 
and  is  named  the  head ;  the  anterior  surface  looks  a  little 
upwards,  the  inferior  edge  being  raised  forwards  by  the  su- 
perior mesenteric  artery  and  vein,  which  pass  behind  it ;  a 
groove  may  be  remarked  on  the  posterior  and  upper  part  of 
the  pancreas ;  this  contains  the  splenic  artery  and  vein. 
The  pancreatic  duct  may  be  seen  by  scraping  off  a  little  of 
the  posterior  surface  of  the  gland  about  its  centre.  This 
duct  is  remarkably  white  and  thin ;  it  commences  in  the 
small  extremity  of  the  gland,  and  extends  to  the  large  end, 
receiving  in  its  course  numerous  branches  on  each  side ;  it 
usually  joins  the  ductus  choledochus ;  it  sometimes,  how- 
ever, opens  into  the  duodenum  distinctly ;  attached  to  the 
head  of  the  pancreas  there  is  sometimes  a  glandular  mass 
of  the  same  structure  as  the  pancreas,  and  opening  by  a 
small  vessel  into  the  pancreatic  duct ;  this  is  named  the 
lesser  pancreas.  The  pancreatic  fluid  is  supposed  to  be  of 
use  in  diluting  the  bile,  and  rendering  it  and  the  contents  of 
the  duodenum  more  miscible  with  each  other.  The  struc- 


184  DUBLIN    DISSECTOR. 

ture  of  the  pancreas  is  similar  to  that  of  the  salivary  glands, 
and  is  thence  called  by  some,  the  abdominal  salivary  gland 
The  pancreas  is  not"  often  found  in  a  morbid  state.,  indura- 
tion of  its  structure  and  calculi  in  its  duct  may  be  occasi- 
onally noticed. 

OF  THE  VESSELS  AND  NERVES  OF  THE  ABDOMEN. 

THE  abdominal  aorta  gives  off  three  large  branches  to 
supply  the  organs  of  digestion,  viz.  the  coeliuc  axis,  the  su- 
perior mesenteric  and  inferior  mesenteric  arteries.  The 
c&liac  axis  may  be  seen  by  tearing  through  the  lesser  omen- 
tum  above  the  lesser  curvature  of  the  stomach,  to  arise  from 
the  forepart  of  the  aorta,  at  the  upper  edge  of  the  pancreas  ; 
it  is  about  half  an  inch  long,  and  divides  into  three  branches, 
viz.  the  gastric,  hepatic,  and  splenic  ;  the  gastric  artery  and 
its  branches  run  between  the  laminae  of  the  lesser  omen- 
turn,  along  the  concave  edge  of  the  stomach,  and  supply 
both  surfaces  of  this  organ.  The  hepatic  artery  accompa- 
nies the  vena  portarum  and  the  biliary  duct  to  the  trans- 
verse fissure  of  the  liver,  first  sending  off  a  small  branch 
to  the  pylorus  (pylorica  superior,)  next  a  large  branch 
(gastro-duodenalis,)  which  descends  behind  the  pylorus 
and  subdivides  into  two  branches,  the  pancreatico-duode- 
nalis  and  gastro-epiploica  dextra  ;  the  former  supplies  the 
pancreas  and  duodenum  ;  the  latter  runs  along  the  convex 
edge  of  the  stomach,  between  the  layers  of  the  great  omen- 
turn  ;  the  hepatic  artery  then  divides  into  the  right  and  left 
hepatic  arteries,  which  supply  the  right  and  left  lobes  of 
the  liver ;  the  right  hepatic  is  the  larger,  and  gives  off  a 
small  branch,  arteria  cystica,  to  the  gall  bladder.  The 
splenic  artery  is  the  longest  and  largest  branch  of  the  coeliac 
axis ;  it  passes  along  the  upper  and  posterior  part  of  the 
pancreas,  to  which  it  gives  many  branches  ;  near  the  spleen 
it  sends  off  the  gastro-epiploica  sinistra,  which  runs  along 
the  convex  edge  of  the  stomach,  between  the  layers  of  the 
great  omentum ;  the  splenic  artery  then  divides  into  five  or 
six  branches,  which  enter  the  foramina  in  the  concave  sur- 
face of  the  spleen  :  from  these  splenic  branches  five  or  six 
small  arteries,  the  vasa  brevia,  pass  to  the  left  or  great  end 
of  the  stomach.  The  superior  mesenteric  artery  arises  about 
half  an  inch  below  the  cceliac  axis,  behind  the  pancreas  ; 
it  descends  in  front  of  the  duodenum,  enters  the  mesentery, 
and  bends  obliquely  towards  the  right  iliac  fossa ;  from  its 
left  or  convex  side  it  sends  off  sixteen  or  eighteen  branches, 
which  supply  the  jejunum  and  the  ileum,  and  from  its  con- 
cave or  right  side  arise  three  branches,  the  ileo-colica,  co- 
lica  dextra,  and  media ;  these  arteries  supply  the  corres- 


DUBLIN    DISSECTOR.  185 

ponding  portions  of  the  colon,  and  inosculate  with  each 
other.  The  inferior  mesenteric  artery  arises  a  little  above  the 
division  of  the  aorta  into  the  iliac  vessels  ;  it  descends  into 
the  left  side,  and  divides  into  three  branches.  First,  the  co- 
lica  sinistra,  which  supplies  the  left  lumbar  colon,  and  in- 
osculates with  the  colica-media ;  second,  the  sigmoid  ar- 
tery, which  supplies  the  sigmoid  flexure  of  the  colon ;  and 
third,  the  superior  hsemorrhoidal,  which  is  distributed  to 
the  rectum. — These  arteries  are  accompanied  by  corres- 
ponding veins,  which  all  unite  to  form  the  vena  portarum ; 
the  inferior  mesenteric  vein  accompanies  the  artery  of  that 
name  to  the  aorta,  and  there  joins  the  superior  mesenteric 
-vein,  which  is  a  very  considerable  vessel;  this  common 
•trunk  then  ascends  behind  the  pancreas,  and  is  joined  by  a 
very  large  vein  from  the  spleen ;  the  confluence  of  the 
splenic  and  mesenteric  veins  forms  the  commencement  of 
the  vena  portarum;  this  vessel  ascends  obliquely  to  the 
:right  side,  surrounded  by  nerves  and  cellular  membrane, 
.-and  enclosed  in  the  lesser  omentum ;  near  the  transverse 
fissure  it  becomes  dilated  (the  sinus  of  the  vena  portarum)  and 
then  divides  into  the  right  and  left  branches ;  the  former  is 
^he  larger,  the  latter  the  longer  of  the  two  ;  each  branches 
out  through  the  liver,  surrounded  by  the  capsule  of  Glisson, 
.and  runs  in  a  transverse  direction  :  injection  shows  their 
:minute  branches  to  communicate  in  the  acini  with  the  pori 
biliarii,  or  with  'the,  commencements  of  the  hepatic  ducts. 

The  nerves  which  supply  the  digestive  organs  are  the 
: eighth  pair,  and  the  splanchnic  branches,  from  the  sympa- 
thetic.: the  eighth  pair  descend  along  the  oesophagus,  and 
;are  distributed  almost  wholly  to  the  stomach  ;  some  few 
branches  pass  along  the  lesser  omentum  to  the  liver.     The 
splanchnic  nerves  are  two  in  number,  a  right  and  left ;  they 
.are  each  formed  by  filaments  from  the  dorsal  ganglions 
of  the  sympathetic  nerve,  in  the  thorax  ;  they  enter  the  ab- 
<domen  either  along  with  the  aorta,  or  perforate  the  crura 
of  the  diaphragm  on  either  side  of  that  vessel ;  in  the  abdo- 
men each  nerve  soon  ends  in  a  large  ganglion,  the  semilu- 
lunar  ganglion,  from  which  numerous  branches  pass  across 
the  aorta,  around  the  coeliac  axis,  and  communicating  with 
each  other,  form  the  nervous  plexus,  named  solar  or  cceliac 
plexus,  from  which  a  fasciculus  of  nerves  extends  along 
each  of  the  branches  of  the  cseliac  artery  to  supply  the  vis- 
cera in  the  epigastric  region  :  thus  a  few  accompany  the 
gastric  artery,  and  communicate  with  the  eighth  pair  on 
the  stomach ;  several  surround  the  hepatic  artery,  and  by 
it  are  conducted  to  the  liver ;  in  like  manner  others  also 
pass  to  the  spleen.    From  the  lower  part  of  the  solar  plexus 
several  large  branches  descend  and  become  attached  to 
16* 


186  '  DUBLIN    DISSECTOR. 

the  superior  and  inferior  mesenteric  arteries,  form  plexuses 
around  these  vessels,  and  receive  additional  branches  from 
the  lumbar  or  abdominal  ganglions  of  the  sympathetic  ; 
these  nerves  then  twine  around  the  mesenteric  arteries  and 
their  branches,  and  are  thus  conducted  to  the  intestines,  in 
the  internal  tunic  of  which  they  terminate.  (See  Anatomy 
LL  the  Nervous  System.)  The  student  may  now  remove 
trie  abdominal  viscera.  Tie  the  lower  extremity  of  the 
u?sophagus  and  the  upper  end  of  the  rectum,  each  with  two 
ligatures,  and  divide  these  tubes  between  them  ;  dissect  out 
tne  vena  cava  from  the  liver,  cut  across  the  hepatic  ves- 
sels, the  co3liac  axis,  the  superior  and  inferior  mesenteric 
arteries  ;  and  then  separate  the  liver,  spleen,  pancreas,  and 
alimentary  canal,  from  their  connexions  to  the  parietes  of 
the  abdomen;  next  clean  the  surface  of  the  abdominal 
aorta  and  vena  cava,  the  right  and  left  kidney,  and  the  re- 
nal capsules.  The  abdominal  aorta  may  be  now  seen  to 
pass  into  the  abdomen,  between  the  crura  of  the  diaphragm, 
opposite  the  last  dorsal  vertebra;  it  then  descends  oblique- 
ly to  the  left  side  of  the  median  line,  and  divides  on  the 
body  of  the  fourth  lumbar  vertebra  into  the  right  and  left 
iliac  arteries.  The  abdominal  aorta  sends  off  the  follow- 
ing branches  :  first,  the  two  phrenic  arteries ;  second,  the 
cceliac  axis;  third, the  superior  mesenteric  artery  ;  fourth, 
the  two  renal  arteries  ;  fifth,  the  spermatic  arteries  ;  sixth, 
the  inferior  mesenteric  artery  ;  also  four  or  five  pair  of 
lumbar  arteries  from  its  posterior  part ;  and  lastly,  from, 
the  angle  of  its  division  the  middle  sacral  artery  descends. 
The  right  and  left  iliac  arteries  descend  obliquely  outwards 
and  backwards;  that  of  the  right  side  is  the  longer  of  the 
two;  opposite  each  ilio-sacral  articulation  each  common 
iliac  artery  divides  into  the  internal  and  external  iliac, 
The  external  proceeds  along  the  inner  side  of  the  psoas 
niMgnus,  and  passing  beneath  Poupart's  ligament,  become;- 
the  femoral  artery  ;  just  above  this  ligament  it  sends  off 
two  branches,  the  epigastric  and  the  circumflex  ilii.  The 
internal  iliac  artery  descends  into  the  pelvis,  and  gives  off 
several  branches,  which  shall  be  noticed  afterwards  in  the 
dissection  of  that  cavity.  The  veins  in  the  abdomen  cor- 
respond to  the  arteries ;  each  external  iliac  vein  ascends 
along  the  inner  side  of  the  artery  of  the  same  name,  and 
near  the  sacrum  is  joined  by  the  internal  iliac  rem,  which 
ascends  from  the  pelvis ;  the  union  of  these  on  each  side 
form  the  common  iliac  reins;  each  of  these  ascends  behind 
its  accompanying  artery,  and  opposite  the  right  side  of  thv 
fourth  or  fifth  lumbar  vertebra  these  veins  unite  and  form 
the  inferior  or  ascending  vena  cava ;  the  left  common  iliae 
vein  is  longer  than  the  right,  and  passes  behind  the  right 


DUBLIN    DISSECTOR.  187 

iliac  artery.  The  vena  cam  ascends  along  the  right  side 
of  the  aorta,  and  receives  the  spermatic,  renal,  and  lumbar 
veins ;  it  lies,  interiorly,  on  the  right  psoas  muscle,  and  on 
the  right  crus  of  the  diaphragm ;  superiorly,  it  inclines 
forwards  and  to  the  right  side,  and  enters  the  h'ssure  in  the 
liver ;  here  it  receives  the  venae  cavse  hepaticse ;  it  then 
passes  through  the  opening  in  the  tendon  of  the  diaphragm, 
and  arrives  at  the  right  auricle  of  the  heart.  On  each  side 
of  the  abdominal  aorta  the  sympathetic  nerves  may  be  seen  ; 
they  pass  from  the  thorax  into  the  abdomen,  beneath  the 
true  ligamentum  arcuatum,  and  then  descend  between  the 
crus  of  the  diaphragm  and  the  psoas  magnus  on  each  side  ; 
in  this  course  they  form  three  or  four  oval  ganglions.  At 
the  last  lumbar  vertebra  these  nerves  pass  outwards  and 
backwards,  and  then  descend  into  the  pelvis. 

The  commencement  of  the  vena  azygos  may  be  observed 
on  the  right  side  of  the  aorta ;  it  is  formed  by  the  first  or 
second  lumbar  veins,  which  communicate  with  the  renal 
and  inferior  lumbar  veins,  and  sometimes  with  the  inferior 
vena  cava.  The  vena  azygos  enters  the  thorax  between 
the  aorta  and  the  right  crus  of  the  diaphragm,  and  then 
yscends  along  the  posterior  mediastinum.  The  thoracic 
duct  also  may  be  seen  to  commence  in  the  abdomen  by  the 
union  of  several  absorbent  vessels  on  the  body  of  the  third 
lumbar  vertebra;  this  vessel  being  larger  here  than  it  is 
above,  has  received  the  name  of  receptaculum  chyli ;  this, 
however,  does  not  always  exist.  The  thoracic  duct  is  co- 
vered at  first  by  the  aorta,  it  then  ascends  obliquely  to  the 
right  side,  and  enters  the  thorax  between  the  aorta  and  ve- 
na azygos.  Let  the  student  next  examine  the  urinary  or- 
gans ;  these  consist — first  of  the  kidneys,  which  secrete 
the  urine  ;  second,  of  the  ureters,  which  convey  this  fluid 
to,  third,  the  urinary  bladder,  which  retains  it  for  a  longer 
or  shorter  time,  and  fourth  the  urethra,  which  discharges  it 
externally. 

DISSECTION    OF    THE    KIDNEYS    AND    URETERS. 

EACH  kidney  is  situated  in  the  posterior  part  of  each  lum- 
bar region,  behind  the  peritonaeum,  between  the  last  rib 
and  the  crest  of  the  ilium  ;  and  corresponds  to  the  two  last 
dorsal  and  two  first  lumbar  vertebra  ;  the  right  kidney  is 
often  a  little  lower  than  the  left,  particularly  if  the  liver  be 
larger  than  usual ;  they  are  each  imbedded  in  a  quantity 
of  soft  adipose  substance,  and  lie  on  the  diaphragm,  psoas, 
and  quadratus  lumborum  muscles  ;  the  right  kidney  is  also 
sometimes  in  contact  with  the  iliacus  intern  us  muscle  :  the 
ascending  colon  and  duodenum  lie  anterior  to  the  right, 
and  the  descending  colon  to  the  left  kidney ;  the  right  is  in 


188  DUBLIN    DISSECTOR. 

contact  with  the  liver  above,  and  with  the  caecum  below  ; 
and  the  left  with  the  spleen  above,  and  the  sigmoid  flexure 
of  the  colon  below.  The  anterior  surface  of  each  is  con- 
vex, the  posterior  is  flat ;  in  the  young  subject  the  surfaces 
are  very  uneven,  the  kidneys  at  that  age  being  lobulated. 
The  external  border  of  each  is  smooth  and  convex,  and 
directed  outwards  and  backwards ;  the  concave  edge  is  of 
much  less  extent,  looks  forwards  and  inwards,  and  contains 
the  arteries,  veins,  and  excretory  duct ;  the  veins  are 
usually,  but  by  no  means  constantly,  anterior ;  the  arte- 
ries, five  or  six  in  number,  are  behind  these  ;  and  the  ureter 
is  posterior  and  inferior  to  both.  The  superior  end  of  each 
kidney  is  larger  and  nearer  to  the  spine  than  the  inferior. 
The  kidney  is  partially  covered  by  peritonaeum,  to  which 
it  is  but  loosely  connected ;  it  has  also  a  capsule  of  cellular 
and  adipose  substance,  and  a  strong  smooth  fibrous  tunic, 
which  adheres  closely  to  its  substance,  preserves  its  form, 
and  is  continued  into  its  interior,  along  the  vessels,  as  far 
as  the  calyces  of  the  kidney. 

[The  usual  weight  of  these  organs  is  from  three  to  five  ounces, 
their  length  from  three  and  a  half  to  five  inches,  their  width  two,  to 
three,  and  their  thickness  a  little  over  an  inch  ;  their  color  is  a  reddish, 
brown.  One  of  these  organs,  is  sometimes  wanting,  in  which  case 
the  one  is  large.  Sometimes  there  is  a  third  kidney,  in  which  case 
two  are  on  one  side,  or  else  the  supernumerary  lies  in  front  of  the 
spine,  or  in  the  pelvis.  Sometimes  one  kidney  is  in  its  usual  situa- 
tion the  other  in  front  of  the  spine  :.  sometimes  the  two  are  united 
across  the  spine,  and  both  have  been  found  in  the  true  pelvis.  In  the 
foetus  and  unlil  the  third  year  afterbirth,  the  kidneys  are  distinctly 
lobulated,  as  in  inferior  animals ;  between  the  third  and  -.tenth  year, 
this  appearance  is  obliterated,  but  becomes  again  very  apparent,  iu 
certain  cases  of  disease.] 

Remove  one  kidney  from  the  subject,  and  divide  it  by  a 
perpendicular  incision  from  the  convex  to  the  concave  edge, 
the  gland  will  then  be  found  to  consist  of  two  distinct  sub- 
stances, the  external  or  vascular,  the  internal  or  mem- 
branous ;  the  external,  vascular,  or  cortical  substance,  forms 
a  covering  for  the  kidney  about  two  lines  thick,  and  sends 
longer  prolongations  into  the  body  of  the  gland,  between 
the  tubular  fasciculi.  The  cortical  substance  is  of  a  dark 
brown  red  colour,  particularly  along  its  internal  margin,  it 
can  be  separated  into  numerous  small  grains;  when  injected 
it  seems  wholly  composed  of  arteries  and  veins.  Internal  to 
this  is  the  tubular  substance,  which  consists  of  fine  vessels  of 
a  pale  colour,  and  very  dense  structure  ;  these  are  arranged 
in  conical  fasciculi,  about  eight  or  ten  in  number ;  the 
base  of  each  is  directed  towards  the  circumference,  the 
apex  towards  the  concave  edge  of  the  kidney  :  the  apices 


DUBLIN    DISSECTOR.  189 

of  these  cones  are  named  papillae, ;  each  papilla  is  perfo- 
rated by  several  small  holes,  through  which  the  urine  may 
be  observed  to  flow  when  the  tubular  cones  are  compressed. 
The  papillae  are  surrounded  by  membranous  sacs  called 
calyces;  each  calyx  contains  one  or  two  papillae,  and  they  are 
five  or  six  in  number  ;  they  are  dense  and  white,  composed 
externally  of  the  fibrous  coat  of  the  kidney,  and  internally 
of  a  fine  mucous  membrane,  which  is  continued  from  the 
ureter  along  the  pelvis  of  the  kidney,  lines  all  the  calyces, 
and  is  reflected  in  the  form  of  a  very  fine  membrane  over 
each  papilla,  and  most  probably  is  continued  into  the 
tubuli  uriniferi.  The  calyces  in  each  extremity,  as  also 
those  in  the  centre,  unite  into  three  small  tubes,  which  be- 
ing of  a  funnel  shape,  are  called  infundibula ;  these  have 
but  a  short  course,  and  soon  terminate  in  the  pelvis  of  the 
kidney.  The  pelvis  is  a  membranous  reservoir  formed  by 
the  union  of  the  calyces  or  the  infundibula,  of  a  flattened 
oval  figure,  placed  behind  the  blood-vessels  of  the  kidney, 
and  terminating  in  the  ureter,  which  it  resembles  in  struc- 
ture. Each  kidney  receives  a  very  large  artery  (the  renal 
or  emulgent)  from  the  aorta  :  this  divides  into  six  or  eight 
branches,  which  enter  the  notch  in  the  gland,  subdivide 
into  numerous  fine  vessels,  which  proceed  between  the 
tubular  portions  to  the  cortex,  in  which  they  terminate  in 
minute  branches,  some  of  which  are  continuous  with  cor- 
responding veins,  others  with  the  commencements  of  the 
tubular  fasciculi ;  these  last  separate  the  urine  from  the 
blood,  and  pour  it  into  the  tubuli  uriniferi,  which  convey  it 
to  the  papillae,  through  the  small  pores  of  which  it  gradu- 
ally flows  into  the  calyces,  and  from  these  into  the  pelvis, 
and  so  into  the  ureter.  The  ureter  is  the  excretory  duct  of 
the  kidney,  and  extends  from  it  to  the  urinary  bladder ; 
each  ureter  is  about  eighteen  inches  long,  and  about  the 
size  of  a  goose  quill ;  its  coats,  are  very  pale,  and  always 
appear  collapsed.  These  vessels  take  an  oblique  course 
downwards  and  inwards  to  the  pelvis ;  each  then  inclines 
a  little  forwards,  continuing  still  to  run  downwards  and  in- 
wards to  the  inferior  and  posterior  part  of  the  bladder, 
passes  obliquely  between  the  muscular  and  mucous  coats 
of  this  viscus,  and  perforates  the  latter  at  the  posterior  angle 
of  the  trigone.  Each  ureter  passes  anterior  to  the  psoas 
magnus,  and  to  the  iliac  vessels,  is  covered  by  the  perito- 
naeum, and  crossed  by  the  spermatic  vessels,  and  near  its 
termination  in  the  male  subject  by  the  vas  deferens  ;  and 
in  the  female  by  the  Fallopian  tubes,  and  broad  ligaments 
of  the  uterus.  In  the  male  each  ureter  attaches  itself  to 
the  bladder  at  the  posterior  extremity  of  each  vesicula 
seminalis,  and  now  much  diminished  in  size,  it  runs  ob- 


190  DUBLIN    DISSECTOR. 

liquely  for  the  extent  of  an  inch  between  the  tunics  of  the 
bladder,  and  opens  internally  (as  will  be  seen  hereafter  in 
the  dissection  of  the  pelvic  viscera)  about  an  inch  and  a 
half  from  the  commencement  of  the  urethra,  and  about  the 
same  distance  from  its  fellow.  In  the  female  the  pelvic 
portion  of  each  ureter  is  longer  than  the  male  ;  they  also 
lie  at  a  greater  distance  from  each  other,  and  perforate  the 
bladder  nearer  to  its  neck  than  in  the  male  subject.  The 
ureter  is  composed  externally  of  a  fibrous  coat,  and  inter- 
nally of  a  pale  mucous  membrane ;  it  is  surrounded  by 
cellular  tissue,  and iin  some  situations  is  partially  covered 
by  peritonaeum,  muscular  fibres  ascend  from  the  bladder 
and  can  be  traced  for  some  inches  along  its  parietes.  The 
ureters  are  larger  at  their  commencement,  and  smaller  at 
their  termination ;  thedntermediate  portion  of  each  is  nearly 
of  one  uniform  diameter. 

[The  ureters  are  sometimes  wanting,  sometimes  terminate  in  a  cul 
de  sac  :  if  the  bladder  is  wanting  they  may  empty  into  the  urethra, 
vagina,  or  rectum  ;  sometimes  there  are  two  for  one  kidney,  they  may 
be  almost  obliterated  or  very  much  dilated,  as  is  sometimes  the  result 
of  an  obstruction  of  the  urethra.] 

Attached  to  the  upper  extremity  of  each  kidney  is  a  small 
gland-like  substance,  named  renal  capsule,  or  supra-renal,  or 
atrabiliary  body ;  of  a  crescentric  shape,  the  base  attached 
to  the  kidney  by  cellular  membrane  and  by  small  blood- 
vessels ;  these  organs  lie  on  the  diaphragm,  and  on  the  se- 
milunar  ganglion  of  each  side,  and  are  covered,  that  on  the 
right  side  by 'the  vena  cava  and  duodenum,  and  on  the  left 
by  the  spleen  and  pancreas  ;  a  vein  also  runs  along  their 
anterior  surface.  In  the  interior  of  each  renal  capsule  we 
find  a  small  triangular  cavity  filled  with  a  brownish  fluid ; 
the  walls  of  this  cavity  are  very  rough,  no  excretory  duct 
can  be  found  leading  from  it.  The  exact  use  of  these  bo- 
dies is  not  ascertained.  The  renal  capsules  in  the  adult  are 
thin,  and  of  a  'brownish  yellow  colour  ;  in  the  foetus  they 
are  very  large  and  vascular,  nearly  equal  to  the  kidney  in 
size,  and  contain  a  quantity  of  reddish  fluid. 

The  kidneys  occasionally  present  the  following  morbid 
appearances  :  inflammation  or  nephritis  is  denoted  by  in- 
creased redness,  vascularity,  and  induration,  and  sometimes 
attended  with  purulent  infiltration ;  when  the  ureter  is  en- 
gaged it  is  also  found  thicker  and  redder  than  natural,  with 
purulent  matter  on  its  inner  surface.  Inflammation  also 
sometimes  ends  in  a  well  defined  abscess  in  the  kidney. 
These  glands  are  frequently  the  seat  of  scrofulous  abscess 
in  which  the  pus  is  white  and  curdy.  Calculi  are  very 
common  in  the  kidney,  sometimes  they  are  small  and  found 
in  the  tubular  portion,  but  generally  they  are  large,  and  fill 


DUBLIN    DISSECTOR.  191 

up  more  or  less  of  the  pelvis  of  the  ureter,  not  unfrequently 
extending  by  a  stalk  a  short  distance  along  that  tube,  and 
presenting  a  branched  appearance  at  the  opposite  extremity 
corresponding  to  the  infundibula.  When  the  calculus  is 
large  and  obstructs  the  flow  of  urine,  the  membranous  por- 
tions of  the  gland  become  dilated,  and  should  the  stone  be 
impacted  lower  down  in  the  ureter,  this  tube  will  also  be- 
come greatly  dilated  above  the  seat  of  the  obstruction ;  in 
such  cases  the  interior  of  the  kidney  will  become  more  and 
more  compressed  and  absorbed,  and  in  time  nothing  will 
remain  but  the  thickened  capsule  with  a  thin  layer  of  vas- 
cular and  glandular  matter,  containing  several  cells  which 
communicate  freely  ;  sometimes  the  whole  of  the  sac  will 
be  found  in  a  state  of  suppuration.  Hydatids  are  common 
formations  in  the  kidney,  they  are  found  on  its  surface  and 
beneath  its  capsule,  they  are  generally  scattered,  each  in 
its  distinct  cell.  The  kidneys  present  great  variety  as  to 
form,  size,  colour,  and  consistence  without  any  known  cor- 
responding difference  in  function.  In  diabetes  they  have 
been  found  large,  vascular,-soft,  and  easily  torn  ;  in  purpura 
with  hematuria  the  lining  membrane  has  appeared  turgid* 
and  petechiae  have  been  distinctly  seen  beneath  it.  The 
kidneys  have  been  the  seat  of  cancer,  fungoid  diseases,  and 
of  melanosis. 

[The  kidney  may  be  either  indurated  or  softened,  hypertrophied 
or  atrophied  as  the  result  of  inflammation  ;  it  may  undergo  the  car- 
tilaginous or  fatty  degeneration  ;  and  it  may  be  converted  almost  en- 
tirely into  bone,  of  which  there  is  an  admirable  specimen,  in  the  col- 
lege museum.  A  parasitic  worm  is  sometimes  found  in  the  human 
kidney,  often  in  that  of  inferior  animals.] 

The  bladder  and  urethra  are  the  next  divisions  of  the 
urinary  organs  to  be  examined  ;  these,  however,  being  pel- 
vic viscera,  we  shall  postpone  the  consideration  of  them  for 
the  present,  as  the  student  should  next  examine  the  deep 
muscles  of  the  abdomen,  viz.-the  diaphragm,  the  quadratus 
lumborum,  psoas  parvus,  psoas  magnus,  and  iliacus  inter- 
nus  of  each  side. 

DISSECTION   OF    THE   DEEP   MUSCLES    OF    THE   ABDOMEN. 

DIAPHRAGM  is  exposed  by  dissecting  off  the  peritonaeum  ; 
it  separates  the  abdomen  from  the  thorax,  being  concave 
towards  the  former  cavity,  convex  towards  the  latter ;  it 
may  be  divided  into  two  portions,  a  superior  transverse 
broad  portion  (the  true  diaphragm)  and  the  inferior  lesser 
portion,  or  the  appendices  or  crura  of  the  diaphragm. 
The  superior  true  diapUragm  is  broad,  thin,-  and  nearly  cir- 
cular ;  it  arises  by  distinct  fleshy  fasciculi,  from  the  pos- 
terior surface  of  the  xiphoid  cartilage,  and*  from  the  inter- 


192  DUBLIN    DISSECTOR. 

nal  surface  of  the  cartilages  of  the  last  true,  and  of  all  the 
false  ribs  ;  these  fasciculi  iridigitate  with  those  of  the  trans- 
versalis  muscle  ;  between  the  extremity  of  the  last  rib  and 
the  side  of  the  spine,  it  arises  from  the  upper  part  of  a 
strong  aponeurosis,  which  covers  the  quadratus  lumber um 
muscle ;  this  is  the  anterior  lamina  of  the  tendon  of  the 
transversalis ;  the  upper  edge  of  this  fascia  being  very 
tense,  particularly  when  the  twelfth  rib  is  everted,  and  ap- 
pearing to  be  extended  as  a  distinct  ligament  between  this 
bone  and  the  first  lumbar  vertebra,  has  received  the  name 
of  the  ligamentum  arcuatum ;  it  is  not  a  distinct  ligament ; 
it  may,  however,  be  named  the  external  or  false  ligamentum 
arcuatum,  to  distinguish  it  from  a  true  and  distinct  liga- 
ment, which  extends  from  the  transverse  process  of  the 
first  to  the  body  of  the  second  lumbar  vertebra ;  this  may 
be  named  the  true  or  internal  ligamentum  arcuatum ;  its 
concavity  looks  downwards,  and  extends  across  the  upper 
extremity  of  the  psoas  magnus  and  the  sympathetic  nerve ; 
from  the  convex  edge  of  this  ligament  the  diaphragm  next 
arises  ;  from  this  extensive  origin  the  fibres  pass  in  differ- 
ent directions,  all  converging  like  radii  from  the  circumfer- 
ence towards  the  centre  of  a  circle ;  the  anterior  backwards 
and  upwards  to  the  edge  of  the  cordiform  tendon,  the  mid- 
dle upwards  and  inwards,  and  then  a  little  downwards,  to 
the  lateral  borders  of  the  central  tendon,  and  the  posterior 
fibres  pass  forwards  and  upwards  to  the  posterior  edge  of 
the  tendon;  the  anterior  fibres  are  the  shortest,  the  lateral 
are  the  longest  and  the  most  arched,  particularly  those  on 
the  right  side,  the  convexity  of  which  is  on  a  level  with  the 
fourth  rib  ;  the  convexity  of  those  on  the  left  side  is  on  a 
level  with  the  fifth  or  sixth  rib.  The  central  tendon  of  the 
diaphragm  is  of  great  transverse  breadth,  and  is  divided 
into  three  portions,  an  anterior,  right  and  left ;  the  first  is 
the  largest,  the  last  is  the  smallest ;  in  regard  to  their  rela- 
tive size  these  divisions  of  the  tendon  are  uncertain  ;  the 
posterior  border  of  the  tendon  is  notched  for  the  insertion 
of  the  crura  or  appendices  of  the  diaphragm ;  the  fibres 
of  this  tendon  generally  run  in  rays  from  behind,  forwards 
and  outwards  ;  they  are  crossed  and  interlaced,  however, 
by  several  bands,  which  have  an  irregular  direction  ;  this 
tendon  is  much  stronger  and  larger  in  proportion  in  the  old 
than  in  the  young,  [and  is  on  a  level  with  the  inferior  ex- 
tremity of  the  second  bone  of  the  sternum.]  Behind  and 
below  this  tendon  are  the  two  crura  or  appendices  of  the 
diaphragm  ;  the  right  crus  is  longer  and  thicker  than  the 
left,  and  arises  by  tendinous  bands  from  the  forepart  of  the 
bodies  of  the  four  first  lumbar  vertebrse.  The  left  is  smaller, 
and  on  a  plane  posterior  to  the  right ;  it  arises  from  the 


DUBLIN    DISSECTOR.  193 

sides  of  the  two  or  three  first  lumbar  vertebrae ;  the  fibres 
of  each  crus  ascend  obliquely  forwards,  are  connected  to 
each  other  by  a  semilunar  tendinous  band  extended  across 
the  aorta  ;  they  then  become  fleshy,  and  a  small  fasciculus 
is  sent  from  each  crus  to  join  the  opposite  ;  these  decussating 
fasciculi  separate  the  oesophageal  from  the  aortic  opening 
in  the  diaphragm ;  of  these  fasciculi,  that  from  the  right 
crus  is  always  the  larger,  and  that  from  the  left  is  generally, 
but  not  always,  anterior.  Each  crus  then  ascends,  and  is 
inserted  into  the  posterior  border  of  the  cordiform  tendon. 

The  right  crus  of  the  diaphragm  is  covered  by  the  vena 
cava,  renal  capsule,  semilunar  ganglion,  and  by  the  liver  ; 
the  left  crus  by  the  aorta,  left  renal  capsule,   semilunar 
ganglion,  spleen  and  stomach.    To  the  thoracic  surface  of 
this  muscle  the  pleurae  are  attached  laterally,  arid  the  pe- 
ricardium and  the  boundaries  of  the  mediastinal  regions 
along  the  middle.    Three  large  openings  are  observed  in 
the  diaphragm  ;  one  for  the  aorta,  one  for  the  vena  cava, 
and  one  for  the  oesophagus.     The  aortic  opening  is  rather 
a  tendinous  passage,  behind  and  between  the  crura  of  the 
diaphragm  ;  it  opens  into  the  abdomen  opposite  the  last 
dorsal  vertebra,  and  nearly  in  the  mesial  line  ;  the  thora- 
cic duct  and  vena  azygos  ascend  through  it,  along  the 
right  side  of  the  aorta  ;  the  splanchnic  nerves,  particularly 
the  left,  sometimes  pass  through  this  opening ;  but  in  ge- 
neral these  nerves  perforate  the  crura  at  a  little  distance 
from  the   aorta.     The   opening  for   the  oesophagus  and 
eighth  pair  of  nerves  is  superior  and  anterior  to  that  for 
the  aorta,  and  is  a  little  to  the  left  of  it ;  it  is  of  an  oval 
figure  ;  its  parietes  are  fleshy,  and  are  formed  by  the  de- 
cussating fasciculi  from  the  crura ;  the  union  or  crossing 
of  these  separate  the  cesophageal  from  the  aortic  opening. 
The  opening  for  the  vena  cava  is  situated  at  the  back  part 
of  the  right  division  of  the  tendon,  anterior  to  the  insertion 
of  the  right  crus  ;  this  foramen  is  perfectly  tendinous ;  it 
is  somewhat  quadrilateral,  and  appears  larger  than  the 
vein  ;  the  edges  are  attached  to  the  vessel,  and  prolonged 
upon  its  coats ;  the  anterior  margin  being  continued  on 
the  abdominal  portion,  and  the  posterior  margin   on  the 
thoracic  portion  of  the  vein.    Posterior  to  the  ensiform 
cartilage  there  is  a  small  triangular  space  on  each  side, 
where  the  diaphragm  is  deficient,  and  through  which  the 
peritonaeum  is  connected  to  the  pleura  and  pericardium ; 
through  this  space  also  the  cellular  membrane  in  the  me- 
diastinum is  continuous  with  that  between  the  abdominal 
muscles.     Use,  it  is  the  principal  muscle  in  inspiration ;  by 
its  action  it  enlarges  the  thorax  in  the  perpendicular  direc- 
tion, for  the  contraction  of  the  crura  draws  down  the  cor- 

17 


194  DUBLIN    DISSECTOR. 

diform  tendon,  and  fixes  it ;  and  then,  when  the  fibres  of 
the  superior  diaphragm  contract,  they  descend,  and  instead 
of  being  convex  towards  the  chest  they  became  nearly 
straight,  so  as  to  present  a  plane  surface  to  the  abdomen, 
looking  downwards  and  forwards.  As  the  fleshy  fibres  are 
longest  at  the  sides,  it  is  here  the  greatest  descent  in  the 
muscle  occurs,  consequently  the  thorax  is  most  enlarged 
on  each  side  beneath  the  lungs.  When  the  diaphragm  re- 
laxes, its  elasticity  and  the  connexion  of  the  pleurae  and 
pericardium  to  its  superior  surface,  cause  it  to  re-ascend, 
so  as  to  present  a  concave  surface  to  the  abdomen,  and  to 
diminish  the  capacity  of  the  thorax.  The  diaphragm  also 
assists  in  coughing,  laughing,  speaking ;  also  in  the  expul- 
sion of  urine  and  faeces,  and  in  the  various  exertions  of  the 
body. 

The  student  may  now  re-consider  the  different  muscles 
which  assist,  and  which  oppose  the  diaphragm  in  respira- 
tion ;  by  this  term  we  mean  the  act  of  taking  into  the  lungs 
a  certain  quantity  of  air,  and  the  subsequent  expulsion  of 
it  from  these  organs ;  the  former  is  termed  inspiration,  the 
latter  expiration.  Inspiration  requires  greater  muscular 
efforts  than  expiration,  which  is  chiefly  effected  by  the 
relaxation  of  the  muscles  of  inspiration,  and  by  the  elasti- 
city of  the  parietes  of  the  thorax.  Inspiration  may  be  per- 
formed with  two  different  degrees  of  force :  the  first,  in 
which  there  is  little  muscular  effort,  is  called  ordinary  in- 
spiration ;  the  second,  in  which  there  is  great  exertion,  is 
called  full  inspiration.  In  the  first,  the  diaphragm  and  the 
intercostal  muscles  are  employed,  but  chiefly  the  former ; 
and  in  the  second,  several  additional  muscles  assist,  viz.  the 
stern o-mastoidei,  the  scaleni,  the  subclavian,  the  serrati 
postici,  and  the  levatores  costarum  ;  also  when  the  supe- 
rior extremities  shall  have  been  fixed,  the  pectoral,  serrati 
magni,  and  latissimi  dorsi  muscles  exert  considerable 
power,  in  elevating  the  ribs  and  drawing  them  outwards, 
so  as  to  enlarge  the  chest  transversely,  and  from  before 
backwards. 

Expiration  also  may  be  performed  in  the  same  different 
degrees  of  intensity  ;  in  the  first  or  ordinary  degree,  the 
elasticity  and  slight  contraction  of  the  abdominal  muscles 
press  the  viscera  against  the  diaphragm,  which  is  already 
receding  in  consequence  of  its  own  relaxation,  and  the  elas- 
ticity of  the  parts  attached  to  its  thoracic  surface ;  when 
expiration  is  performed  in  the  second  or  forced  degree,  the 
elasticity  of  the  ribs  and  of  their  cartilages  opposes  the  in- 
tercostal muscles :  the  triangulares  sterni  also  depress  the 
cartilages,  and  the  abdominal  muscles  and  levatores  ani, 
by  increasing  their  contracting  force,  push  the  abdominal 


DUBLIN    DISSECTOR.  195 

viscera  against  the  diaphragm,  and  draw  down  the  ribs ; 
the  serrati  postici  inferiores  and  quadrati  lumborum  mus- 
cles assist,  also  the  latissimi  dorsi  muscles,  by  acting  to- 
wards the  ilium  ;  and  should  the  last  rib  be  fixed,  it  is  pos- 
sible for  the  intercostal  muscles  to  depress  the  superior 
ribs,  and  so  to  become  muscles  of  expiration. 

QUADRATUS  LUMBORUM,  is  a  thick,  flat  muscle,  between 
the  anterior  and  middle  layers  of  the  transversalis  abdomi- 
nis  tendon,  posterior  to  the  psoas,  the  kidney,  and  the  dia- 
phragm ;  and  anterior  to  the  sacro-lumbalis  ;  it  arises  ten- 
dinous from  the  posterior  fourth  of  the  spine  of  the  ilium, 
and  from  the  ilio-lumbar  ligament ;  the  fibres  ascend  ob- 
liquely inwards,  and  are  inserted  into  the  extremity  of  the 
transverse  processes  of  the  four  first  lumbar  vertebrae,  and 
of  the  last  dorsal ;  also  into  the  internal  surface  of  the  pos- 
terior half  of  the  last  rib.  Use;  to  bend  the  spine  to  one 
side,  to  depress  the  last  rib,  thus  assisting  in  expiration ; 
when  both  muscles  act,  they  support  the  spinal  column  in 
the  perpendicular  direction. 

PSOAS  PARVUS  is  situated  between  the  psoas  magnus  and 
the  vertebrae,  it  arises  fleshy  from  the  side  of  the  last  dorsal 
and  first  lumbar  vertebra,  ends  in  a  long  flat  tendon,  which 
descends  on  the  inner  side  of  the  psoas  magnus,  and  is  in- 
serted broad  and  thin  into  the  linea  ilio-pectinaea,  or  brim 
of  the  pelvis,  also  into  the  fascia  iliaca  and  fascia  lata,  be- 
hind the  femoral  vessels. — Use;  it  assists  in  bending  the 
body  forwards,  or  in  raising  the  pelvis ;  it  also  makes 
tense  the  crural  arch,  in  consequence  of  its  attachment  to 
the  fascia  lata.  This  muscle  is  often  wanting  ;  when  pre- 
sent, it  is  situated  internal  and  anterior  to  the  psoas  mag- 
nus, and  is  partly  concealed  by  the  diaphragm,  the  renal 
vessels,  the  peritonaeum  and  at  its  insertion  by  the  external 
iliac  vein  and  artery. 

PSOAS  MAGNUS,  long,  round,  and  thick  in  the  centre, 
small  at  its  extremities,  fleshy  at  its  superior,  tendinous  at 
its  inferior  :  it  extends  along  the  sides  of  the  lumbar  verte- 
brae, of  the  brim  of  the  pelvis,  and  the  anterior  and  inner 
part  of  the  thigh  ;  it  arises  fleshy  from  the  side  of  the  body 
of  the  two  last  dorsal,  arid  from  the  bodies  and  transverse 
processes  of  all  the  lumbar  vertebrae,  also  from  the  inter- 
vertebral  ligaments ;  the  fibres  all  descend,  at  first  verti- 
cally, afterwards  obliquely  outwards,  along  the  brim  of  the 
pelvis,  and  beneath  Pou part's  ligament ;  the  muscle  then 
becomes  tendinous,  and  descends  obliquely  inwards  and 
backwards,  and  is  inserted  tendinous  into  the  back  part  of 
the  lesser  trochanter,  also  fleshy  into  a  ridge  below  that 
process.  Use ;  to  flex  the  thigh  on  the  pelvis,  or  the  body 
on  the  thigh ;  it  also  rotates  the  thigh  outwards ;  in  stand- 


196 


DUBLIN    DISSECTOR. 


ing  it  supports  the  spine,  and  prevents  it  bending  back- 
wards, and  in  walking  it  is  particularly  engaged ;  it  then 
raises,  and  throws  forwards  and  outwards  the  lower  extre- 
mity. This  muscle  is  situated  between  the  psoas  parvus 
and  the  quadratus  lumborum  above,  and  between  the  for- 
mer muscle  and  the  iliacus  below ;  and  in  the  groin,  be- 
tween the  sartorius  and  the  pectinseus ;  its  insertion  is  be- 
tween the  vastus  internus  and  the  pectina^us  ;  it  is  covered 
in  the  lumbar  region  by  the  diaphragm,  the  kidney,  and 
its  vessels ;  also  on  the  right  side  by  the  vena  cava,  and  on 
the  left  by  the  aorta ;  in  the  middle  or  pelvic  division  of  its 
course  it  lies  between  the  external  iliac  vessels  and  the  iliac 
muscle,  and  the  anterior  crural  nerve ;  in  its  lower  or  in- 
guinal division  it  is  partly  covered  by  the  femoral  artery 
and  nerve,  and  by  some  of  their  branches,  also  by  the  in- 
guinal ganglia,  and  by  a  considerable  quantity  of  cellular 
membrane.  The  psoas  lies  anterior  to  the  transverse  pro- 
cesses of  the  lumbar  vertebras,  to  the  quadratus  lumborum, 
the  lumbar  nerves,  the  inner  edge  of  the  iliacus  internus, 
and  the  capsular  ligament  of  the  hip ;  the  lumbar  nerves 
or  the  lumbar  plexus  in  general  run  through  the  psoas, 
perforating  its  posterior  portion ;  a  large  bursa  -separates 
its  tendon  from  the  pubis  and  from  the  capsular  ligament ; 
this  bursa  sometimes  communicates  with  the  synovial 
membrane  of  the  hip  joint.  A  smaller  bursa  lies  between 
the  point  of  the  lesser  trochanter  and  this  tendon.  The 
tendon  of  the  psoas  is  formed  in  the  outer  or  iliac  side  of 
the  muscle,  and  receives  the  insertion  of  the  fibres  of  the 
iliacus  internus. 

[Varieties.  This  muscle  sometimes  also  arises  by  fasciculi  which 
ascend  from  the  first,  second,  and  third  bones  of  the  sacrum ;  some- 
times there  is  a  distinct  fasciculus  bordering  on  the  pelvis,  which 
joins  the  tendon  of  the  principal  muscle  near  the  trochanter,  and  oc- 
casionally this  muscle,  and  the  Hiacus  internus  are  distinct  from 
their  origins  to  their  insertions.] 

ILIACUS  INTERNUS,  flat,  or  concave,  radiated  or  triangular, 
arises  fleshy  from  the  transverse  process  of  the  last  lumbar 
vertebra,  from  the  inner  margin  of  three  anterior  fourths 
of  the  crest  of  the  ilium,  from  the  two  anterior  spinous  pro- 
cesses, and  from  the  intervening  notch,  from  the  brim  of 
the  acetabulum,  and  from  the  capsular  ligament,  also  from 
the  iliac  fossa,  and  from  the  strong  aponeurosis,  the  iliac 
fascia,  which  covers  it.  The  iliac  fascia  is  attached  to  the 
crest  of  the  ilium,  to  Poupart's  ligament,  as  far  inwards  as 
the  iliac  artery,  behind  which  it  passes  and  becomes  con- 
tinuous with  the  pubic  portion  of  the  fascia  lata ;  the  fibres 
of  this  muscle  all  descend  obliquely  inwards,  join  the  outer 


DUBLIN    DISSECTOR.  197 

side  of  the  tendon  of  the  psoas  magnus,  and  are  inserted 
along  with  it,  or  rather  into  it ;  the  inferior  fibres,  fleshy, 
are  also  inserted  into  the  anterior  and  inner  surface  of  the 
femur,  below  the  lesser  trochanter.  Use ;  to  assist  the  psoas 
in  flexing  the  thigh,  and  in  rotating  it  outwards;  it  also 
adducts  it ;  it  protects  the  fore  part  of  the  eapsular  liga- 
ment, and  in  flexion  of  the  thigh  draws  it  out  of  the  angle 
between  the  neck  of  the  femur  and  the  edge  of  the  aceta- 
bulum. 

This  muscle  fills  up  the  concavity  of  the  iliac  fossa ;  on 
the  right  side  it  is  covered  by  the  caecum,  on  the  left  by  the 
colon ;  in  the  groin  this  muscle  is  partly  covered  by  the 
sartorius,  and  it  lies  on  the  rectus  and  on  the  eapsular  liga- 
ment. We  may  next  proceed  to  the  dissection  of  the  pe- 
rinseum  and  the  viscera  of  the  pelvis. 


SECTION  IV. 

DISSECTION    OF    THE     PERINEUM    IN    THE    MALE, 

[The  muscles  to  be  examined  in  this  region  are  fourteen  m  number, 
so  arranged  as  to  form  two  single  muscles,  and  six  pairs  as  follows. 


SINGLE. 

2.  Sphincter  Internus  or  Orbicularis, 


1.  Sphincter  Ani,  Vide  p. 


3.  Erectores  or  Compressores  Penis,  (  t*     >«     g^g 

4.  Acceleratores  Urinaa  or  Ejaculatores  Seruinis,  $ 

5.  Transversales  Perinaei, 

6.  Levatoren  Ani,  Vide  p.     203. 

7.  Compressores  Urethrse,  "     "      204. 

8.  Coccygei,  "     "      208. 
PLACE  the  subject  on  the  back,  bend  the  thighs  and  knees 

upon  the  trunk,  and  secure  them  in  the  same  position  as  if 
you  were  about  to  perform  the  lateral  operation  of  litho- 
tomy ;  the  dissection  will  be  fasciliated  if  the  pelvis  be 
raised  by  a  block  placed  beneath  it ;  moderately  distend 
the  lower  end  of  the  rectum  with  sponge  or  curled  hair ; 
introduce  a  staff  or  catheter  into  the  urethra  and  bladder ; 
secure  the  penis  to  it  by  a  ligature,  and  raise  up  the  scro- 
tum. The  perinaum  extends  from  the  os  coccygis  behind, 
to  the  arch  of  the  pubis  before ;  is  bounded  on  each  side 
by  the  rami  of  the  pubis  and  ischium,  by  the  tuber  ischii, 
and  by  the  great  sacro-sciatic  ligament,  which  extends  from 


198  DUBLIN    DISSECTOR, 

that  process  to  the  side  of  the  sacrum  and  coccyx  ^  the 
glutseus  maximus  overhangs  this  ligament ;  the  tuberosity 
and  ramus  of  the  ichium  can  be  felt  through  the  integu- 
ments, also  (unless  the  subject  be  very  fat)  the  rarnus  of 
the  pubis  leading  obliquely  upwards  on  each  side  to  the 
symphysis:  the  integuments  of  the  perineum  and  scrotum 
are  generally  of  a  dark  brownish  colour  in  the  adult,  and 
of  a  reddish  hue  in  the  child ;  very  thin  around  the  anus, 
and  covering  the  scrotum,  but  dense  in  the  intermediate 
space  :  along  the  mesial  line,  a  prominent  hard  ridge  is  ob- 
servable, the  raphe  of  the  perinseum ;  this  line  commences 
in  front  of  the  anus,  and  extends  along  the  perineeum, 
scrotum  and  penis,  as  far  as  the  prepuce  of  the  latter. 
Dissect  off'  the  integuments  from  this  region,  and  we  ex- 
pose posteriorly  a  cutaneous  muscle  (the  sphincter  ani)  sur- 
rounding the  anus,  and  anteriorly  a  stong  fascia  covering 
the  muscles  of  the  perinseum,  the  crura  penis,  and  the  cor- 
pus spongiosum  urethrre. 

SPHINCTER  ANI  is  flat,  thin,  oval,  pale,  and  open  in  the 
middle  ;  it  arises  from  a  ligamentous  substance,  which  ex- 
tends from  the  os  coccygis  to  the  rectum ;  the  fibres  de- 
scend obliquely  forwards,  expanding  on  either  side  nearly 
as  far  outwards  as  the  tuberosity  of  the  ischiurn ;  at  the 
posterior  part  of  the  anus  this  muscle  divides  into  two  fas- 
ciculi ;  which  pass,  one  at  each  side  of  this  opening,  and 
unite  at  its  anterior  part,  thus  encircling  this  orifice  ;  insert- 
ed into  the  raphe  in  the  integuments,  and  into  the  superfi- 
cial fascia  ^  a  fasciculus  of  it  also  perforates  the  latter,  and 
is  inserted  into  the  common  central  point  of  the  perinseum  ; 
a  point  which  will  be  more  fully  seen  when  the  fascia  shall 
have  been  raised;  Use;  to  close  the  anus;  it  may  also 
draw  downwards  the  bulb  of  the  urethra;  this  muscle  is 
almost  constantly  in  a  state  of  contraction,  and,  like  all  the 
sphincter  muscles,  belongs  to  the  class  of  mixed  muscles. 
One  of  its  surfaces  looks  downwards,  and  is  superficial,  the 
other  looks  upwards,  and  is  connected  to  the  levatores  ani 
muscles;  one  edge  is  internal,  the  other  external.  It  is 
superficial ;  its  lateral  extent  is  much  greater  in  some  sub- 
jects than  in  others:;  a  few  of  its  external  fibres  are  di- 
vided in  the  first  incision  in  the  lateral  operation  of  litho- 
tomy ; — beneath  and  internal  to  this  muscle  we  may  expose 
the  following,  with  very  little  dissection. 

SPHINCTER  INTERNUS  vel  OREICULARIS,  consists  of  a  thick, 
but  pale  fasciculus  of  muscular  fibres,  which  encircles  the 
lower  extremity  of  the  rectum,  having  no  attachment  to 
the  coccyx  behind,  and  but  a  slight  one  to  the  central  point 
before :  it  is  in  close  contact  with  the  mucous  membrane 
of  the  intestine ;  its  use  is  similar  to  that  of  the  last  des- 


DUBLIN    DISSECTOR.  199 

cribed  muscle.  Its  surfaces  are  internal  and  external,  its 
edges  superior  and  inferior.  Anterior  to,  and  on  each  side 
of  the  anus,  we  find  beneath  the  integuments  a  condensed 
cellular  texture,  covering  the  other  muscles  in  the  peri- 
nseum ;  this  is  the  superficial  fascia ;  it  is  continued  from 
the  inner  side  of  one  thigh  across  the  perinseum  to  the 
opposite,  adhering  to  the  rami  of  the  ischium  and  pubis 
on  each  side,  by  tendinous  fibres ;  this  fascia  is  very  dense 
about  the  middle  of  the  perinseum ;  posteriorly,  on  either 
side  of  the  anus,  it  is  loaded  with  soft,  large-grained,  adi- 
pose substance :  anteriorly  it  extends  over  the  scrotum, 
and  becomes -thin  and  fine,  like  reticular  membrane,  and 
continuous  with  the  superficial  fascia  from  the  abdomen. 

This  fascia  covers  the  vessels,  and  all  the  muscles  of  the 
perineum,  except  the  two  sphincters  of  the  anus.  Separ- 
ate this  fascia  from  one  side  of  the  perinseum,  and  reflect 
it  towards  the  opposite  ;  its  density  and  close  connexion  to 
the  lateral  boundaries  of  this  region  will  then  become  ob- 
vious ;  a  number  of  veins  and  nerves,  and  a  quantity  of  fat 
also  will  be  observed  ;  when  the  latter  is  dissected  away, 
those  muscles  of  the  perineum,  which  are  attached  to  the 
penis  and  urethra,  will  appear,  covered,  however,  by  a  fine 
but  dense  aponeurosis,  which  may  be  next  dissected  off; 
these  muscles  are  six  in  number,  three  on  each  side,  viz. 
the  erector  penis,  transversalis  perin^i,  and  accelerator 
urina?.*  If  the  perinasum  be  divided  by  a  transverse  line 
drawn  from  one  tuberosity  of  the  ischium  to  the  other,  into 
an  anterior  and  posterior  part,  we  shall  find  that  the  ante- 
rior triangular  space,  or  the  ureihral  region,  contains  in  the 
male  subject  the  six  muscles  just  named,  also  the  crura 
penis  and  the  corpus  spongiosum  urethrse :  the  posterior 
triangular  division,  or  the  anal  region,  contains  the  lower 
extremity  of  the  rectum,  surrounded  by  the  cutaneous  and 
deep  sphincters,  also  on  each  side  of  this  intestine  a  con- 
siderable quantity  of  fat,  filling  up  the  space  between  the 
side  of  the  rectum  and  the  obturator  internus  muscle  and 
fascia;  this,  the  ischio-rectal  space,  is  bounded  superiorly, 
that  is,  separated  from  the  pelvis  by  the  levator  ani  mus- 
cle, and  inferiorly  is  closed  by  the  fascia  and  integuments ; 
the  fat  is  from  two  to  three  inches  in  depth ;  when  this  mass 
is  dissected  out  of  the  space  which  it  fills,  the  levator  ani 
muscle,  covered  by  the  ischio-rectal  layer  of  the  pelvic 
fascia,  [or  the  deep  perinatal  fascia]  will  be  seen  extended 
from  the  internal  surface  of  the  pelvis  to  either  side  of  the 
rectum,  and  to  the  coccyx,  so  as  to  form  a  partition  be- 


*  A  knowledge  of  these  fasciae  will  explain  the  resistance  which  this  structure 
presents  to  collections  of  urine  or  of  pus  from  coining  to  the  surface. 


200  DUBLIN    DISSECTOR. 

tween  the  pelvis  and  the  perinseum. — First  examine  the 
muscles  in  the  anterior  part  of  the  perinseum ;  the  erector 
or  compressor  penis  is  most  external,  and  lies  on  the  crus 
penis ;  the  accelerator  urinoe  extends  along  the  middle  of 
the  perinaeum,  attached  to  its  fellow  along  the  raphe,  and 
covering  the  urethra;  the  transversalis  perinsei  connects 
the  posterior  extremities  of  these  muscles.  Immediately 
in  front  of  the  rectum,  in  the  middle  line,  and  behind,  but 
connected  to  the  bulb  of  the  urethra,  is  a  small,  white,  ten- 
dinous spot,  composed  of  condensed  cellular  tendinous  and 
muscular  substance ;  into  this  many  of  the  perinseal  mus- 
cles are  inserted ;  it  is,  therefore,  called  the  central  point  of 
the  perinseum,  or  the  common  point  of  insertion  to  the  mus- 
cles of  the  perinseum. 

ERECTOR,  or  COMPRESSOR  PENIS,  long  and  flat,  narrow  at 
each  extremity,  broader  in  the  middle,  arises  tendinous  and 
fleshy  from  the  inner  surface  of  the  tuber  ischii,  and  from 
the  insertion  of  the  great  or  inferior  sacro-sciatic  ligament, 
the  fibres  proceed  forwards,  upwards,  and  inwards,  adher- 
ing to  the  edges  of  the  rami  of  the  pubis  and  ischium,  and 
covering  the  crus  penis.  The  fleshy  fibres  terminate  in  a 
tendinous  expansion,  which  inclines  forwards,  upwards, 
and  outwards,  and  is  inserted  into  the  fibrous  membrane  of 
the  corpus  cavernosum  or  crus  penis.  Use ;  to  draw  down 
the  penis ;  it  also  contributes  to  the  erection  or  distention 
of  this  organ  by  propelling  the  blood  into  it,  and  by  the 
compression  of  the  veins  against  the  bone  preventing  the 
free  return  of  this  fluid  through  these  vessels :  it  is  the  most 
exteinal  of  the  muscles  in  this  situation,  it  covers  and  ad- 
heres to  the  crus  penis. 

ACCELERATOR  URINJE,  or  EJACULATOR  SEMINIS,  is  in  the 
middle  of  the  perinaeum,  extends  from  the  front  of  the  rec- 
tum to  the  back  part  of  the  scrotum,  and  is  attached  to  its 
fellow  along  the  mesial  line ;  it  arises  first,  by  tendinous 
fibres  from  the  triangular  or  inter-osseous  ligament,  inter- 
nal to  the  erector  penis;  secondly,  by  a  broad  tendon, 
which  is  common  to  the  opposite  muscle,  and  which  lies 
above  the  urethra,  between  it  and  the  pubis ;  thirdly,  more 
anteriorly  by  a  tendinous  expansion  from  the  side  of  the 
corpus  cavernosum  penis.  The  posterior  and  middle  fibres 
descend  inwards ;  the  anterior  fibres,  which  are  longer, 
descend  obliquely  backwards  and  inwards ;  all  the  fibres 
are  inserted  along  with  those  of  the  opposite  muscle  into  the 
middle  tendinous  line  or  raphe  of  the  perinaeum,  which  ex- 
tends from  the  common  central  point  to  the  back  of  the 
scrotum. — Use;  to  expel  the  last  drops  of  urine  and  semen, 
also  to  distend  the  corpus  spongiosum  urethrae  by  propel- 
ling the  blood  into  its  cells.  The  posterior  origin  of  this 


DUBLIN    DISSECTOR.  201 

muscle  is  overlapped  by  the  erector  penis,  and  by  the  per- 
inseal  vessels  and  nerves ;  some  of  its  fibres  extend  in  some 
cases  outwards,  as  far  as  the  ramus  of  the  ischium,  and 
arise  from  the  bone ;  the  origin  of  the  middle  fibres  lies 
above  the  urethra,  and  that  of  the  anterior  is  external  to 
the  crus  penis.  The  anterior  fibres  of  this  pair  of  muscles, 
by  converging  towards  the  middle  line,  resemble  the  letter 
Y.  The  accelerators  urinas  muscles  fill  up  the  middle  of 
the  perinseum,  cover  the  bulb,  and  encircle  the  urethra  an- 
terior to  it.  Separate  these  muscles  from  each  other  along 
the  mesial  line,  and  detach  one  of  them  from  the  corpus 
spongiosum  urethree ;  then  by  examining  its  deep  surface, 
its  origin,  particularly  that  which  lies  above  the  urethra, 
anterior  to  the  bulb,  will  be  more  distinctly  seen. 

TRANSVERSALIS  PERIN^EI,  is  thin  and  weak,  often  indis- 
tinct, and  sometimes  wanting ;  it  arises  from  the  inside  of 
the  tuberosity  of  the  ischium,  above  the  erector  penis  mus- 
cle, the  fibres  pass  transversely  inwards  and  a  little  down- 
wards, and  are  inserted  into  the  central  point  of  the  perin- 
reurn,  behind  the  accelerator  urinae  muscle.  Use,  to  fix  the 
central  point,  and  support  the  anus  ;  it  may  also  dilate  the 
bulb.  This  muscle  is  covered  by  the  sphincter  ani,  and  by 
the  superficial  fascia,  a  small  artery  (transversalis  perinsei) 
runs  along  its  anterior  edge ;  it  lies  on  the  levator  ani,  is 
connected  to  it  by  cellular  membrane,  and  in  some  cases 
is  intimately  joined  to  it.  In  some  subjects  a  second  mus- 
cle may  be  observed  taking  a  transverse  course  (the  trans- 
versalis alter ;)  this  arises  from  the  ramus  of  the  ischium, 
proceeds  obliquely  forwards  and  inwards,  and  is  inserted 
into  the  accelerator  urinse.  The  transverse  perinsei  mus- 
cles are  very  irregular  in  size  in  different  persons,  in  some 
being  found  very  distinct  and  strong,  in  others  a  few  pale 
and  scattered  fibres  only  point  out  their  course  and  situa- 
tion :  the  dissector  is  frequently  obliged  to  cut  oft'  a  few 
fasciculi  from  the  levatores  ani  muscles,  to  make  even  an 
appearance  according  with  the  description  given  in  books. 
Between  the  three  last  described  muscles  on  each  side,  we 
may  remark  a  triangular  space,  which  is  bounded  exter- 
nally by  the  crus  penis  and  the  erector  penis  muscle,  in- 
ternally by  the  urethra  and  accelerator  urina3 ;  the  base  is 
posteriorly,  and  is  formed  by  the  transversalis  perinsei 
muscle.  This  space  contains  a  quantity  of  fat,  also  the 
perinatal  artery,  veins,  and  nerves,  branches  of  the  pudic 
vessels  and  nerves ;  into  this  space,  on  the  left  side  of  the 
perinseum,  the  operator  must  sink  his  knife  in  the  lateral 
operation  of  lithotomy,  in  order  to  lay  bare  the  groove  in 
the  staff.  In  this  incision  the  transversalis  muscle  and 
artery  of  the  perinseum  must  be  divided.  Next  dissect  off 


202  DUBLIN    DISSECTOR. 

the  erector  penis  from  the  crus  penis,  also  the  accelera- 
tores  urinse  muscles  from  the  bulb  and  corpus  spongiosum 
urethrae ;  detach  the  transverse  muscle  from  its  attach- 
ments, and  remove  the  vessels  and  cellular  membrane  out 
of  the  triangular  space  just  now  described  ;  then  press  the 
bulb  of  the  urethra  to  one  side,  from  the  crus  penis,  and 
between  these  two  bodies  we  may  observe  a  strong  liga- 
mentous  substance,  the  fibres  passing  in  different  direc- 
tions ;  this  is  the  triangular  ligament  of  the  urethra  or  the 
inter-osseous  ligament  of  the  perineum.  The  apex  of  this  lig- 
ament is  above,  and  is  weak  and  cellular,  being  lost  in 
front  of  the  symphysis  pubis,  on  the  dorsal  vessels  of  the 
penis  ;  the  sides  are  connected  to  the  rami  of  the  pubis  and 
ischium ;  its  base  is  directed  towards  the  rectum,  being 
connected  in  the  middle  line  to  the  central  point  of  the 
perinseum,  on  each  side  of  which  it  is  thin  and  weak,  and 
gradually  lost  on  the  surface  of  the  levator  ani.  Through 
this  ligament  the  urethra  passes  about  an  inch  below  the 
inferior  edge  of  the  symphysis  pubis,  and  as  this  canal 
passes  through  it,  the  ligament  sends  a  lamina  on  it  in  each 
direction,  one  anteriorly  on  the  bulb,  the  other  posteriorly 
on  the  membranous  portion  of  the  urethra  and  prostate 
gland ;  the  former  is  called  the  anterior,  the  latter  the  pos- 
terior layer  of  the  triangular  ligament,  and  they  are  separated 
from  each  other  by  Cowper's  glands  and  the  artery  of  the 
bulb.  The  anterior  layer  of  the  triangular  ligament  is  expand- 
ed on  the  bulb,  and  gives  to  it  the  peculiar  glistening  ap- 
pearance it  now  presents ;  it  also  retains  it  in  its  situation, 
and  prevents  it  being  detached,  as  will  appear  if  you  en- 
deavour to  draw  it  out  of  its  place.  The  posterior  layer  is 
continued  backwards  around  the  membranous  part  of  the 
urethra  to  the  prostate  gland,  the  capsule  for  which  it 
forms,  and  then  becomes  continuous  superiorly  and  later- 
ally with  the  reflections  of  the  pelvic  fascia  on  the  neck  of 
the  bladder.  Divide  a  few  fibres  of  the  anterior  layer  of  this 
ligament,  and  by  a  little  dissection  you  will  expose  on  each 
side  of  the  bulb  a  small  glandular  body,  Cowper's  or  the 
anti-prostatic  glands  ;  these  are  two  in  number,  about  the 
size  of  a  small  pea,  situated  at  each  side  of,  and  behind  the 
bulb,  below  the  membranous  part  of  the  urethra,  between 
the  layers  of  the  triangular  ligament,  and  closely  connect- 
ed to  the  artery  of  the  bulb ;  they  are  covered  anteriorly 
by  the  acceleratores  urinee  muscles,  and  by  the  anterior 
layer  of  the  triangular  ligament ;  from  each  a  small  deli- 
cate duct,  about  an  inch  in  length,  passes  forwards,  and 
opens  obliquely  into  the  lower  and  lateral  part  of  the  ure- 
thra, at  a  little  distance  anterior  to  the  bulb.  Dissect  away 
all  the  cellular  membrane  at  the  side  of  the  rectum,  be- 


DUBLIN    DISSECTOR.  203 

tween  it  and  the  tuber  ischli;  you  will  thus  expose  the 
greater  portion  of  the  levator  ani  muscle ;  press  the  rec- 
tum to  the  opposite  side,  and  you  will  then  observe  how 
this  muscle,  posteriorly,  and  the  triangular  ligament,  an- 
teriorly, close  the  inferior  opening  of  the  pelvis,  and  sep- 
arate this  cavity  from  the  perinseum.  Divide  the  triangu- 
lar ligament  on  one  side  from  the  rami  of  the  pubis  and 
ischium,  and  draw  it  over  towards  the  bulb  of  the  urethra, 
which,  together  with  the  rectum,  press  or  fasten  with  a 
tenaculum,  towards  the  opposite  tuberosity  of  the  ischium. 
In  separating  this  ligament  from  the  bone,  the  pudic  artery 
and  its  terminating  branches  will  be  seen  ;  we  thus  also 
expose  more  fully  the  levator  ani  muscle. 

LEVATOR  ANI,  flat,  thin,  and  broad,  situated  at  the  inferior 
part  of  the  pelvis,  broader  above  at  its  origin  than  below 
at  its  insertion  ;  arises  fleshy  from  the  posterior  part  of  the 
symphysis  pubis  below  the  true  ligaments  of  the  bladder ; 
thin  and  tendinous  from  the  obturator  fascia,  and  from  the 
ilium  above  the  thyroid  hole  ;  thick,  tendinous,  and  fleshy 
from  the  inner  surface  of  the  ischium,  and  from  its  spinous 
process  ;  the  fibres  descend  obliquely  inwards,  by  the  side 
of  the  neck  of  the  bladder  and  rectum ;  the  anterior  pass- 
ing more  backwards  than  the  others,  while  the  posterior 
are  more  transverse  or  horizontal,  inserted,  the  anterior  or 
pubic  fibres  into  the  central  point  of  the  perineeum,  and 
into  the  forepart  of  the  rectum,  uniting  with  the  fibres  from 
the  opposite  side.  These  anterior  fibres  descend  along  the 
side  of  the  prostate  gland  and  the  membranous  part  of  the 
urethra ;  the  middle  fibres  into  the  side  of  the  rectum,  pass- 
ing internal  to  the  sphincters,  and  united  to  the  outer  sur- 
face of  the  longitudinal  fibres  of  the  intestine ;  the  poste- 
rior fibres  into  the  back  part  of  the  rectum,  and  into  a  ten- 
dinous raphe,  extending  from  it  to  the  os*coccygis,  in  which 
raphe  the  muscles  from  the  opposite  sides  unite,  also  into 
the  two  last  bones  of  the  coccyx.  Use,  to  raise  the  rectum 
when  this  intestine  has  been  protruded  by  the  efforts  of  the 
abdominal  muscles  to  expel  its  contents  ;  it  also  assists  in 
closing  this  intestine,  it  compresses  the  vesiculae  seminales 
and  prostate  gland  ;  the  anterior  portion  supports  the  peri- 
nseum  by  raising  the  common  central  point,  and  may  also 
compress  and  close,  like  a  sphincter,  the  membranous  por- 
tion of  the  urethra ;  the  levatores  ani  complete  the  inferior 
boundary  of  the  pelvis  and  abdomen,  and  are  opposed  to 
the  diaphragm  in  respiration,  being  muscles  of  expiration. 
The  two  levatores  ani  muscles  resemble  a  funnel,  with  two 
openings  in  it  inferiorly :  the  concavity  directed  towards 
the  pelvis,  the  convexity  to  the  perinseum  ;  through  the  an- 
terior aperture  the  urethra  passes,  through  the  posterior  the 


204  DUBLIN    DISSECTOR. 

rectum.  On  the  perinseal  surface  of  this  muscle  are  placed 
the  muscles,  the  triangular  ligament,  and  the  adipose  sub- 
stance of  which  we  have  spoken ;  its  pelvic  surface  is  co- 
vered by  the  peritonaeum  and  by  the  pelvic  fascia,  which 
cannot  be  seen  in  the  present  dissection,  but  which  shall  be 
noticed  presently. 

At  the  anterior  edge  of  each  levator  ani  muscle  fleshy 
fibres  may  be  observed  to  surround  the  membranous  part 
of  the  urethra  very  closely.  These  fibres,  particularly  at 
their  insertion,  will  in  general  be  found  so  united  to  the  le- 
vatores  ani,  that  they  may  be  considered  as  portions  of 
these  muscles ;  they  have,  however,  been  described  differ- 
ently by  different  anatomists,  no  doubt  in  consequence  of 
the  different  appearance  they  present  in  different  subjects, 
and  from  the  different  mode  in  which  the  dissection  has 
been  conducted  ;  Mr.  Wilson  describes  them  as  follows : 

COMPRESSORES  URETHRA ;  each  arises  by  a  tendon  from 
the  inside  of  the  symphysis  pubis,  about  one-eighth  of  an 
inch  above  the  lower  edge  of  the  arch,  and  at  nearly  the 
same  distance  beneath  the  anterior  ligaments  of  the  blad- 
der, to  which,  and  to  the  tendon  of  the  opposite  muscle,  it 
is  connected  by  loose  cellular  membrane  ;  the  tendon  is  at 
first  round,  but  becomes  flat  as  it  descends,  and  is  parallel 
to  and  in  contact  with  its  fellow ;  it  then  ends  in  fleshy 
fibres,  which  increase  in  breadth,  and  which  approaching 
the  upper  surface  of  the  membranous  portion  of  the  ure- 
thra, separate  from  those  of  the  opposite  muscle,  descend 
along  the  side  of  the  membranons  portion  of  the  urethra, 
and  folding  beneath  it,  again  approach  the  muscle  of  the 
opposite  side,  and  are  inserted  with  it  into  a  narrow  tendi- 
nous line,  which  becomes  lost  in  the  common  central  point 
of  the  perinseum.  Use,  to  compress,  contract,  close,  and 
elevate  the  membranous  portion  of  the  urethra;  these 
fibres  encircle  the  narrowest  part  of  the  urethra,  that  por- 
tion which  is  just  behind  the  bulb,  and  may,  by  their  con- 
traction during  life,  form  such  an  impediment  to  the  pas- 
sage of  an  instrument  into  the  bladder,  as  may  lead  the 
surgeon  to  suspect  the  presence  of  a  stricture,  when  in  re- 
ality no  alteration  of  structure  exists.  The  origin  of  these 
muscles  is  occasionally  distinguished  from  the  levatores  arii, 
by  some  small  veins  which  pass  from  the  side  of  the  neck 
of  the  bladder  to  join  the  trunk  of  the  dorsal  veins  of  the 
penis,  but  their  insertion  is  confounded  with  these  muscles 
in  perinaeo  behind  the  bulb.* 

Let  the  student  next  replace  the  triangular  ligament,  &c., 

*  Mr.  Guthrie  states,  that  they  arise  from  two  tendinous  lines,  one  on  the  upper, 
the  other  on  the  lower  surface  of  the  urethra,  thence  the  fleshy  fibres  pass  trans- 
versely outwards,  and  are  inserted  into  the  upper  part  of  the  ramus  of  the  ischium. 


DUBLIN    DISSECTOR.  205 

and  then  re-consider  the  several  parts  before  him,  in  refer- 
ence to  the  operation  of  lithotomy  :  he  has  already  ex- 
amined the  triangular  space  between  the  erector  penis  and 
accelerator  urina3  muscles,  into  which  the  knife  of  the  ope- 
rator is  to  sink  in  order  to  reach  the  groove  in  the  staff'; 
this  space  has  been  fully  opened,  and  the  staif  can  be 
plainly  felt  or  seen  passing  above  the  bulb  through  the 
membranous  part  of  the  urethra  into  the  bladder :  behind 
and  below  the  bulb  is  the  rectum  ;  and  close  to  the  rami  of 
the  pubis  and  ischium  are  the  internal  pudic  vessels :  the 
large  artery  from  the  pudic,  called  the  deep  transverse  ar- 
tery, or  the  artery  of  the  bulb,  may  also  be  observed  pass- 
ing in  the  substance  of  the  triangular  ligament,  about  an 
inch  below  the  symphysis  pubis.  Hence  then,  in  order  to 
lay  bare  the  staff'  without  injury  to  the  more  important 
parts  which  surround  it,  we  should  endeavour  to  open  the 
urethra  as  near  to  the  base  of  the  triangular  ligament  as 
possible,  as  we  shall  thus  be  most  likely  to  avoid  the  ar- 
tery of  the  bulb.  Suppose  the  knife  of  the  operator  to  be 
lodged  in  the  groove  of  the  staff',  and  then  to  be  pushed 
along  it  into  the  bladder,  the  student  will  perceive  that  at 
that  moment  the  posterior  layer  of  the  triangular  ligament, 
the  anterior  fibres  of  the  levator  ani,  and  the  left  lateral 
lobe  of  the  prostate  gland,  must  be  divided,  and  from  this 
view  he  may  also  learn  that  the  rectum  will  be  protected 
from  injury  if  the  staff  be  well  raised  into  the  arch  of  the 
pubes,  its  groove  turned  a  little  to  the  left  side,  and  the 
wrist  of  the  operator  depressed,  so  as  to  elevate  the  point 
of  the  knife,  and  thus  direct  it  on  into  the  bladder ;  as  to 
withdrawing  the  knife  the  student  may  now  learn  in  what 
direction  this  can  be  done  with  safety  and  effect,  and  what 
parts  require  to  be  divided  ;  it  is  to  be  withdrawn  slowly 
and  steadily  in  a  direction  backwards  and  outwards,  nearly- 
parallel  to  the  line  of  the  cutaneous  incision,  the  edge  so 
lateralized  as  to  avoid  cutting  the  rectum  posteriorly,  or 
the  pudic  artery  externally  ;  in  this  part  of  the  operation 
the  middle  fibres  of  the  levator  ani  must  be  divided,  also 
the  adipose  substance  on  its  perinasal  surface.  The  student 
may  now  withdraw  the  staff  from  the  bladder,  and  pass  it 
again  and  again  along  the  urethra  into  that  cavity ;  he  will 
soon  perceive  how  apt  the  point  of  the  instrument  is  to  de- 
scend into  the  sinus  of  the  bulb,  and  the  necessity  of  de- 
pressing the  handle  of  the  staff,  in  order  to  raise  the  point 
into  the  membranous  part  of  the  urethra. 

[This  is  owing  to  the  fact,  that  the  membranous  portion  of  the 
urethra  does  not  terminate  at  the  end  and  bottom  of  the  bulb,  but 
some  lines  above  and  before  this,  hence  when  the  point  of  the  staff  is 
lodged  in  the  bulb,  it  should  be  withdrawn  a  few  lines,  to  disentangle 

18 


'206  DUBLIN    DISSECTOR. 

it  from  any  fold  of  the  mucous  membrane,  and  then  by  depressing 
the  handle  of  the  instrument,  the  point  will  be  raised  up  to  the  open- 
ing through  the  triangular  ligament.] 

At  the  same  time  he  should  observe,  that  the  latter  is 
about  an  inch  below  the  arch  of  the  pubes,  and  that,  there- 
fore, the  point  of  the  instrument  is  not  to  be  too  much  ele- 
vated, otherwise  it  may  lacerate  the  upper  part  of  the  ure- 
thra, and  injure  some  large  veins  that  may  be  found  in  this 
situation.  The  student  may  now  also  examine  what  occu- 
pies the  space  between  the  urethra  and  the  pubes  ;  imme- 
diately above  that  canal  is  the  upper  portion  of.  the  trian- 
gular ligament,  attached  to  the  crura  penis  ;  behind  and 
above  this  are  one  or  two  large  veins  from  the  dorsum  of 
the  penis,  these  enter  the  pelvis  along  the  upper  surface  of 
the  prostate  gland ;  above  these  is  a  smooth  dense  liga- 
ment, the  pubic  ligament,  which  is  attached  to  the  lower  edge 
of  the  symphysis  pubis,  and  rounds  off  the  angle  between 
the  opposite  rami. 

Posterior  to  the  levator  ani,  and  overlapped  by  the  glu- 
tceus  maximus,  is  the  following  small  muscle  : 

COCCYGEUS,  triangular,  at  the  inferior  and  posterior  part 
of  the  pelvis,  behind  and  above  the  levator  ani,  arises  nar- 
row from  the  inner  surface  of  the  spine  of  theischium,  the 
fibres  expand  along  the  inner  or  lesser  sacro-sciatic  liga- 
ment, and  are  inserted,  fleshy  and  tendinous,  into  the  extre- 
mity of  the  sacrum  and  side  of  the  coccyx:  Use,  to  sup- 
port the  os  coccygis  and  to  assist  in  closing  the  inferior  and 
posterior  part  of  the  pelvis ;  this  muscle  is  between  the  le- 
vator ani  and  the  glutrcus  maximus ;  it  is  more  distinctly 
seen  within  the  pelvis. 

Next  let  the  student  divide  the  central  point  of  the  peri- 
nseum,  separate  the  rectum  from  the  bulb,  and  draw  the 
former  a  little  downwards  from  the  bladder  and  prostate 
gland  :  he  will  thus  expose  the  inferior  or  posterior  surface 
of  the  neck  of  the  bladder,  the  flat  posterior  surface  of  the 
prostate  gland,  also  the  vesiculic  seminales,  the  termina- 
tions of  the  vasa  deferentia,  and  the  commencement  of  the 
urethra,  but  the  most  important  part  to  direct  the  attention 
to,  is  a  small  triangular  space  or  portion  of  the  bladder, 
just  above  and  behind  the  prostate  gland,  which  is  bounded 
on  either  side  by  the  vasa  deferentia  and  vesiculse  semi- 
nales, posteriorly  by  the  cul  de  sac  of  the  peritonaeum,  and 
anteriorly  by  the  prostate  gland  which  forms  the  apex  of 
this  triangle  ;  within  this  space  the  muscular  coat  of  the 
bladder  is  in  contact  with  the  rectum,  and  from  the  cavity 
of  the  latter  the  former  organ  may  be  perforated  during 
life  without  injuring  any  important  part;  this  space  is 
about  three  inches  and  a  half,  or  four  inches  from  the  anus, 


DUBLIN    DISSECTOR.  207 

and  is  selected  by  some  surgeons  as  the  best  situation  for 
tapping  the  bladder  in  case  of  retention  of  urine,  when  a 
catheter  cannot  be  passed  through  the  urethra.  The  stu- 
dent may  now  proceed  to  examine  the  pelvic  viscera ;  for 
this  purpose,  separate  the  left  cms  penis  from  the  bone, 
also  the  left  border  of  the  triangular  ligament,  (if  not  al- 
ready done,)  and  detach  the  levator  ani  muscle  of  the  left 
side  from  the  bone ;  with  the  hand  separate  the  cellular 
and  aponeurotic  bands  which  lie  superior  to  this  muscle  ; 
then  divide  the  symphysis  pubis,  or  saw  the  left  os  pubis 
about  half  an  inch  external  to  the  symaphysis,  divide  the 
left  ilio-sacral  articulation,  cut  through  the  psoas  muscle 
and  iliac  vessels,  and  then  remove  the  os  innominatum  and 
lower  extremity  of  the  left  side  ;  the  pelvic  viscera  will  re- 
main in  the  concavity  of  the  sacrum  and  of  the  opposite 
os  innominatum.  These  viscera  will  be  rendered  more  dis- 
tinct by  a  little  dissection,  first,  moderately  inflating  the 
bladder  through  the  ureter,  a  ligature  having  been  tied 
around  the  penis,  the  rectum  also  may  be  moderately  dis- 
tended with  curled  hair  or  a  sponge,  and  attached  to  the 
spine  by  a  ligature. 

The  pelvic  portion  of  the  peritonaeum  should  be  first  attend- 
ed to ;  this  membrane  may  be  now  seen  to  descend  along 
the  sides  and  fore  part  of  the  rectum  to  within  about  three 
or  four  inches  of  the  anus,  whence  it  is  reflected  on  the 
lower  and  back  part  of  the  bladder :  the  line  of  this  reflec- 
tion is,  in  the  recumbent  position  of  the  subject,  opposite1 
the  lower  margin  of  the  third  piece  of  the  sacrum;  in  the 
erect  posture  it  will  be  found  on  a  level  with  the  junction 
of  the  sacrum  and  coccyx  ;  the  peritonaeum  is  reflected  on 
the  bladder  between  the  middle  of  the  vesicular  seminales, 
it  then  ascends  on  the  back  part  and  sides  of  this  organ  to 
its  superior  fundus,  whence  it  is  continued  to  the  abdomi- 
nal muscles ;  below  the  line  of  its  reflection  on  the  blad- 
der, or  below  the  cul  de  sac,  we  may  again  take  notice  of 
the  triangular  space  on  the  inferior  fundus  of  the  bladder, 
before  alluded  to,  as  the  situation  in  which  that  viscus  can 
be  punctured  from  the  rectum,  in  case  of  retention  of  urine. 
The  reflections  of  the  peritonaeum  from  each  side  of  the 
rectum  to  the  back  part  of  the  bladder,  are  called  the  pos- 
terior ligaments  and  the  folds  which  this  membrane  forms, 
one  on  each  side  between  the  bladder  and  the  iliac  fossa, 
are  named  the  lateral  ligaments  of  the  bladder ;  these  shall 
be  more  particularly  noticed  presently.  Remark  the  curved 
course  of  the  rectum,  its  dilatation  near  the  anus,  also  the 
connexion  of  the  peritonaeum  to  its  upper  and  middle 
thirds,  and  observe  that  the  lower  third  of  this  intestine  is 


208  DUBLIN    DISSECTOR. 

completely  below  and  unattached  to  this  membrane.    Next 
study  the  connexions  of  the  unirary  bladder. 

Vescica  Urinaria,  when  contracted,  is  situated  in  the  ante- 
rior and  inferior  part  of  the  pelvis  behind  and  below  the 
pubes  ;  when  distended  it  occupies  more  or  less  of  the  hy- 
pogastric  region ;  when  contracted,  it  appears  of  a  flatten- 
ed triangular  form,  the  base  towards  the  rectum,  the  apex 
behind  the  lower  edge  of  the  syrnphysis  pubis ;  when  dis- 
tended, it  presents  an  oval  figure,  the  larger  end  towards 
the  rectum,  the  smaller  and  anterior  end  towards  the  recti 
abdominis  muscles,  between  the  pubes  and  the  peritonaeum  ; 
the  axis  of  the  bladder  is  a  line  directed  through  its  cavity 
from  one  extremity  to  the  other ;  the  posterior  end  of  this 
line,  if  prolonged  would  touch  the  extremity  of  the  coccyx, 
and  if  continued  anteriorly  it  would  reach  the  linea  alba, 
midway  between  the  pubes  and  the  umbilicus.  In  the  very 
young  subject,  the  bladder  is  of  a  pyriform  figure,  and  is 
principally  lodged  in  the  hypogastdc  region. 

[The  form  and  situation  of  the  bladder  vary  very  much,  according 
to  age,  sex,  and  distention.  In  the  foetus  arid  infant  the  bladder  is 
nearly  cylindrical  in  form,  and  almost  entirely  in  the  cavity  of  the 
abdomen,  the  cavity  of  the  pelvis  proper  at  that  time,  being  so  small, 
as  not  to  contain  it,  particularly  after  the  secretion  of  urine  com- 
mences. In  the  adult  male  the  form  of  the  organ  is  ovoidal,  the, 
longest  diameter  being  vertical  to  the  plane  of  the  superior  strait  of 
the  pelvis.  In  the  adult  female,  who  has  borne  children,  the  bladder 
is  more  spheroidal  in  form,  is  more  capacious  than  in  the  male,  and 
its  longest  diameter  is  transverse.  This  difference  appears  to  be  ow- 
ing to  the  pressure  exerted  upon  the  bladder,  by  the  gravid  uterus. 
We  find  also,  that  the  position  of  the  bladder  is  changed  during  utero- 
gestation,  particularly  in  the  advanced  stage,  when  this  organ,  is 
somewhat  raised  and  projected  forward  over  the  pubis,  and  the  urethra 
is  drawn  up  behind,  and  nearly  parallel  to  the  symphisis  pubis.  On 
this  account,  if  necessary  to  draw  off  the  urine,  the  point  of  the 
catheter  being  introduced  into  the  orifice  of  the  urethra,  the  handle 
must  be  depressed  between  the  thighs,  nearly  to  the  fissure  of  the 
nates.  If  the  bladder  of  the  adult  be  but  partially  distended  with 
urine,  it  will  remain  within  the  cavity  of  the  pelvis  proper,  but  when 
fully  distended,  the  superior  fundus,  rises  up  above  the  brim  of  the 
pelvis,  into  the  abdomen,,  and  in  some  cases,  of  over  distention,  it  has 
ascended  above  the  umbilicus.  The  capacity  of  the  bladder,  in  the 
adult  will  average  about  one  pint,  but  there  is  a  great  difference  in 
individuals  in  this  respect,  the  capacity  being  greater  in  those  who 
are  in  the  habit  of  retaining  their  urine  for  a  length  of  time,  than  in 
others,  and  this  is  thought  by  Cruveilhier,  to  be  one  cause  of  the 
greater  capacity  in  the  female  ;  they,  from  the  habits  of  society,  be- 
ing more  often  obliged  to  retain  the  urine,  for  a  long  time.  Again 
the  capacity  of  the  bladder  varies  with  certain  morbid  conditions,  the 
organ  in  some  cases,  being  so  contracted  as  scarcely  to  contain  an 
ounce  of  fluid,  while  in  others,  it  is  so  dilated  as  to  hold  several  pints. 


DISSECTOR.  209 

According  to  the  anatomist  above  named,  the  bladder  is  proportion- 
ably  larger,  before  than  after  birth.] 

The  bladder  is  connected  to  the  parietes  and  to  the  visce- 
ra of  the  pelvis  by  folds  of  the  peritonaeum,  and  by  the  re- 
flections of  the  pelvic  fascia.  The  folds  of  the  peritonaeum 
are  termed  false  ligaments,  and  are  five  in  number,  viz.  two 
posterior,  two  lateral,  and  one  superior  :  the  true  ligaments 
are  reflections  of  the  pelvic  fascia,  and  are  four  in  number, 
two  anterior  and  two  lateral.  We  shall  first  consider  the 
false  ligaments,  or  the  folds  of  the  peritonaeum,  which  serve 
to  connect  the  bladder  to  the  pelvic  viscera.  The  posterior 
ligaments  of  the  bladder  are  two  in  number,  one  on  each' 
side ;  they  lead  from  the  fore  part  of  the  rectum  to  the 
back  part  of  the  bladder ;  each  is  of  a  semilunar  form,  its 
concavity  looking  forwards  and  upwards ;  in  this  fold  are 
contained  the  ureter  posteriorly,  and  the  obliterated  hypo- 
gastric  artery  anteriorly  ;  between  the  posterior  ligaments 
the  cul  de  sac  of  the  peritonaeum  descends.  This  mem- 
brane will  be  also  found  thrown  into  one  or  two  semilunar 
folds  on  the  posterior  surface  of  the  bladder,  provided  this 
viscus  be  in  a  state  of  contraction ;  these  disappear,  how- 
ever, when  it  becomes  distended  :  hence  it  may  be  inferred, 
that  these  folds  are  designed  to  admit  of  the  more  easy  dis- 
tention  of  this  organ.  The  lateral  ligaments  extend,  one  on 
each  side,  from  the  lateral  regions  of  the  bladder  to  the 
iliac  fossae ;  each  contains  in  its  duplicature  the  vas  defe- 
rens  in  the  male  subject,  and  the  ligamentum  teres  of  the 
uterus  in  the  female.  The  superior  ligament  extends  from 
the  summit  of  the  bladder  to  the  recti  muscles ;  this  portion 
of  the  peritonaeum  is  partially  reflected  over  the  remains 
of  the  urachus  and  of  the  hypogastric  vessels.  Detach  the 
peritonaeum  from  the  right  iliac  fossa,  and  gently  draw  the 
bladder  and  rectum  from  the  pelvis,  we  shall  then  observe 
that  the  neck  and  sides  of  the  former  are  retained  in  their 
situation  by  the  reflection  of  a  strong  fascia  (the  pelvic 
fascia)  from  the  parietes  of  the  pelvis  upon  this  viscus ; 
these  reflections  are  the  true  ligaments  of  the  bladder.  The 
pelvic  fascia  may  be  considered  as  a  continuation  of  the  iliac 
fascia ;  it  descends  from  behind  the  iliac  vessels  and  from 
the  brim  of  the  pelvis,  to  which  it  adheres,  and  lines  the 
parietes  of  the  cavity  as  low  down  as  the  upper  edge,  or 
the  origin  of  the  levator  ani  muscle ;  here  the  pelvic  fascia 
divides  into  two  laminaB,  between  which  this  muscle  is  en- 
closed :  the  external  lamina  is  named  the  obturator  fascia, 
[or  deep  perineal  fascia]  the  internal  the  vesical  fascia. 
The  obturator  fascia  descends  between  the  obturator  inter- 
nus  and  levator  ani  muscles,  adhering  very  closely  to  the 
former,  and  sends  off  the  ischio-rectal  layer  of  fascia  which 
18* 


210  DUBLIN    DISSECTOR. 

covers  the  perinosal  aspect  of  the  levator  ani  muscle ;  the 
obturator  fascia  is  then  inserted  inferiorly  into  the  great 
sciatic  ligament,  into  the  tuber  ischii,  and  into  the  rami  of 
the  ischium  and  pubis,  where  it  is  continuous  with  the  trian- 
gular ligament  of  the  urethra,  which  ligament  thus  appears 
to  be  the  continuation  of  the  obturator  fascia,  from  one 
side  of  the  pelvis  to  the  other.  The  vesical  fascia  covers 
and  adheres  to  the  internal  surface  of  the  levator  ani,  lying 
between  it  and  the  peritonaeum  ;  this  fascia  descends  ante- 
riorly to  the  lower  edge  of  the  symphysis  pubis,  and  late- 
rally to  a  level  with  a  line  carried  from  this  point  round 
to  the  spine  of  the  ischium ;  from  the  pubes  it  is  reflected 
on  the  upper  surface  of  the  prostate  gland,  and  on  the 
neck  of  the  bladder,  forming  the  anterior  true  ligaments 
of  this  organ;  laterally  it  is  reflected  from  the  pelvis  on 
the  side  of  the  prostate,  and  on  the  lower  part  of  the  side 
of  the  bladder,  just  above  the  outer  edge  of  each  vesicula 
seminalis,  and  thus  it  forms  the  true  lateral  ligaments  of 
the  bladder;  posteriorly  the  vesical  fascia  becomes  thin 
and  cellular,  is  attached  to  the  side  of  the  rectum,  and  lost 
on  the  nerves  and  vessels  passing  into  and  out  of  the  pel- 
vis. The  vesical  fascia  thus  forms  a  pouch  on  each  side 
of  the  bladder,  which  assists  in  closing  the  pelvis ;  it  also 
fixes  the  pelvic  viscera,  supports  the  peritonaeum,  and  re- 
sists the  pressure  of  the  abdominal  muscles  and  diaphragm. 
This  fascia  is  perforated  by  several  blood-vessels. 

The  -anterior  ligaments  of  the  bladder  are  two  in  number  ; 
they  arise,  each,  from  the  lower  margin  of  the  pubis  by  the 
side  of  the  symphysis ;  pass  backwards  and  upwards  on 
the  upper  surface  of  the  prostate  gland,  and  expand  on 
the  anterior  part  of  the  bladder  ;  many  of  their  fibres  may 
be  seen  to  become  continuous  with  the  muscular  fibres  of 
the  bladder,  their  inferior  or  convex  surface  is  united  to 
the  posterior  layer  of  the  triangular  ligament.  A  depres- 
sion exists  between  these  two  ligaments,  along  which  the 
dorsal  reins  of  the  penis  pass  from  beneath  the  arch  of  the 
pubes  to  the  side  of  the  bladder  in  their  course  to  the  inter- 
nal iliac  veins,  in  which  they  terminate ;  the  pelvic  fascia, 
however,  is  not  deficient  between  these  ligaments,  but  is  con- 
tinued from  one  to  the  other,  so  as  to  line  this  depression 
and  cover  the  superior  surface  of  these  veins.  The  true 
lateral  ligaments  of  the  bladder  are,  one  on  each  side  ;  each 
is  continuous  with  the  anterior  ligament,  and  is  formed  by 
the  reflection  of  the  pelvic  fascia  from  the  inner  surface 
of  the  levator  ani  to  the  side  of  the  prostate  gland  and  of 
the  bladder. 

The  superior  and  anterior  extremity  of  the  bladder  is 
sometimes  named  the  superior  fundus;  the  posterior  ex 


DUBLIN    DISSECTOR.  211 

tremity,  which  presses  against  the  rectum,  the  inferior  fun- 
dus;  the  intervening  portion  is  called  the  body,  and  that 
part  which  is  connected  to  the  pubes  the  cervix ;  the  latter 
is  surrounded  by  the  prostate  gland,  very  little,  however, 
of  this  gland  being  above  it,  a  little  dissection  can  separate 
the  base  of  this  gland  from  this  part  of  the  bladder,  which 
it  overlaps,  the  cervix  is  thus  made  more  distinct,  and  it 
then  presents  somewhat  a  conical  figure;  in  the  adult  it 
lies  nearly  horizontal,  below  and  behind  the  pubes ;  in  the 
child  it  is  more  vertical.  If  the  bladder  be  moderately  dis- 
tended it  will  be  found  to  present  six  regions,  on  each  of 
which  some  important  object  may  be  noticed.  1st,  The 
superior  region,  is  in  contact  posteriorly  with  the  convolu- 
tions of  the  small  intestines,  and  anteriorly  with  the  recti 
abdorninis  muscles^  to  it  are  attached  the  urachus  and  ob- 
literated umbilical  arteries  ;  posterior  to  these  this  region 
is  covered  by  peritonaeum,  whereas  anterior  to  them  this 
membrane  is  deficient.  If  the  bladder  be  much  distended, 
this  region  is  sometimes  found  to  incline  to  the  left  side. 
2nd,  and  3rd ;  The  lateral  regions,  are  contiguous  to  the 
sides  of  the  pelvis,  to  the  vesical  fascia,  and  to  the  levatores 
ani  muscles ;  descending  obliquely  backwards  along  this 
region  on  each  side,  we  find  the  vas  deferens  crossing  over 
the  obliterated  umbilical  artery  above,  and  over  the  ureter 
below,  thus  passing  internal  to  both,  or  nearer  to  the  me- 
sial line  ;  the  peritonaeum  adheres  to  so  much  of  each  late- 
ral region  of  the  bladder  as  lies  posterior  to  the  vas  defe- 
rens while  that  portion  anterior  to  it  is  deficient  of  this 
serous  covering.  4th,  The  anterior  region  is  behind  the  recti 
muscles,  the  pubes,  the  pubic  ligament,  and  the  triangular 
ligament  of  the  urethra  ;  all  this  region  wants  the  perito- 
nseal  covering ;  towards  its  inferior  part  we  observe  the 
anterior  ligaments  of  the  bladder,  between  them  the  dorsal 
veins  of  the  penis,  and  below  them  the  neck  of  the  bladder 
surrounded  by  the  prostate  gland,  5,  The  posterior  region 
is  contiguous  to  the  rectum  in  the  male,  to  the  uterus  in 
the  female,  and  in  either  sex  occasionally  to  the  convolu- 
tions of  the  small  intestines  ;  all  this  region  is  covered  by 
peritonaeum.  6th,  The  inferior  region,  in  the  female,  lies  on 
the  ureters  and  on  the  vagina  ;  in  the  male,  on  the  vesicu- 
lae  seminales,  the  intervening  cul  de  sac  of  peritonseum,  the 
rectum  and  the  prostate  gland ;  the  superior  and  posterior 
part  of  this  region  is  covered  by  the  peritonaeum  ;  but  an- 
terior to  the  line  of  the  reflection  of  this  membrane,  from 
the  bladder  to  the  rectum,  is  the  triangular  portion  of  this 
region,  in  which  the  peritonseum  is  deficient,  and  which 
has  been  already  attended  to,  as  the  situation  in  which  the 


212  DUBLIN    DISSECTOR. 

operation  of  tapping  the  bladder  from  the  rectum  may  be 
performed. 

The  coats  of  the  bladder  are  four,  viz.  1st,  the  serous,  or 
peritoneal ;  2nd,  the  muscular ;  3rd,  the  cellular ;  4th,  the 
mucous ;  the  serous  is  but  a  partial  coat,  it  covers  all  the 
posterior  surface,  the  posterior  part  of  the  upper  and  lower 
fundus  ;  also  the  posterior  part  of  each  side.  All  the  ante- 
rior region,  the  fore  part  of  the  sides,  and  of  the  upper  and 
lower  regions,  are  therefore  uncovered  by  peritoneum ; 
when  the  bladder  is  distended  there  is  more  of  this  organ 
in  proportion  covered  by  this  membrane  than  in  its  con- 
tracted state.  The  peritonseal  covering  of  the  bladder  is 
very  dense,  it  may  be  easily  dissected  off  the  following. 
2nd,  The  muscular  coat  consists  of  fibres  which  are  strong- 
er and  redder  than  the  muscular  fibres  on  any  of  the  hol- 
low viscera  ;  they  take  different  directions ;  those  of  the 
superficial  layer  run  chiefly  in  a  longitudinal  direction, 
are  connected  anteriorly  and  inferiorly  to  the  anterior  liga- 
ments of  the  bladder,  and  superiorly  to  the  urachus,  poste- 
riorly and  inferiorly  to  the  base  of  the  prostate  gland ; 
these  fibres  are  stronger  on  the  anterior  and  posterior  sur- 
faces than  on  the  sides  of  the  bladder  :  on  the  latter  regions 
they  run  obliquely  and  are  fewer  in  number.  The  anterior 
fibres,  from  having  a  fixed  attachment,  are  called  by  some 
the  delrusor  urince  muscle  :  the  deep  fibres  mostly  take  a  cir- 
cular direction,  are  weak  superiorly,  but  strong  near  the 
cervix,  where  they  arc  supposed  by  some  to  act  as  a  sphinc- 
ter muscle  ;  these  circular  fibres  which  have  received  this 
name,  may  be  more  distinctly  seen  by  everting  the  bladder, 
and  dissecting  off  the  mucous  membrane  near  the  orifice 
of  the  urethra  on  each  side  of  the  uvula.  At  the  anterior 
part  of  the  inferior  region  there  is  a  compact  layer  of  white 
dense  fibrous  substance,  into  which  the  muscular,  particu- 
larly the  longitudinal,  fibres  of  the  bladder  are  inserted, 
but  which  itself  does  not  appear  to  be  very  muscular  ex- 
cept near  the  cervix;  this  structure  will  be  found  to  cor- 
respond with  a  particular  region,  which  will  be  noticed 
presently  in  the  interior  of  the  bladder,  and  which  is  called 
the  trigone,  or  the  velum.  In  addition  to  the  longitudinal 
and  circular  fibres,  a  deeper,  but  only  a  partial  lamina  of 
fibres  can  be  seen  having  a  reticular  arrangement.  Be- 
neath the  muscular  is  the  3rd,  or  the  cellular  coat ;  it  invests 
the  whole  organ,  is  very  elastic,  and  seldom  contains  any 
adipose  substance.  Open  the  bladder  by  a  perpendicular 
incision  through  its  anterior  part ;  and  the  4th.  or  the  mu- 
cous coat,  will  be  observed ;  this  is  pale,  and  thrown  into 
many  folds,  particularly  if  the  bladder  had  been  empty,  foi 
this  membrane  has  no  contractile  power;  through  it  the 


DUBLIN    DISSECTOR.  213 

muscular  fibres  project,  presenting  a  reticulated  appear- 
ance, and  very  frequently  the  mucous  membrane  forms 
pouches,  or  small  sacks,  between  these :  inferiorly  is  seen 
the  orifice  of  the  urethra  ;  is  is  somewhat  of  a  crescentric 
figure,  a  very  small  tubercle  (the  uvula)  projecting  into  it 
from  below :  posterior  to  this  the  mucous  membrane  pre- 
sents a  smooth  and  dense  appearance  throughout  a  small 
triangular  space  called  the  velum  or  trigone ;  at  the  poste- 
rior angles  of  this  space  the  orifice  of  each  ureter  may  be 
observed,  the  line  extending  between  these  forms  the  base 
of  this  triangle ;  this  line  is  somewhat  semilunar,  and  con- 
tains strong  muscular  fibres  ;  the  sides  of  the  trigone  are 
defined  by  lines  drawn  from  each  ureter  to  the  uvula ; 
each  is  from  an  inch  to  an  inch  and  a  half  in  length  ;  be- 
neath the  membrane  covering  each  of  these  lines,  pale  mus- 
cular fibres  may  in  general  be  found;  these  have  been 
named  by  Mr.  Bell,  the  muscles  of  the  ureters,  who  describes 
each  as  arising  from  the  vesical  extremity  of  the  ureter,  and 
thence  descending  obliquely  forwards  and  inwards,  to  be 
inserted  by  a  tendon  common  to  its  fellow  into  the  uvula. 
The  use  which  he  assigns  to  them  is,  to  restrain  the  termi- 
nation of  the  ureters,  and  preserve  the  obliquity  of  the  pas- 
sage of  these  tubes  through  the  coats  of  the  bladder  while 
it  is  being  contracted ;  for,  says  he,  without  this  provision, 
the  urine  would  be  sent  retrograde  into  the  ureters,  instead 
of  forward  into  the  urethra.  These  lines,  however,  seldom 
present  this  structure  so  distinctly  as  has  been  described, 
and  how  far  their  supposed  use  is  correctly  ascribed  to 
them  is  very  questionable.  The  uvula  of  the  bladder  is  a 
small  eminence  at  the  apex  of  the  trigone,  much  better 
marked  in  some  than  in  others ;  it  is  merely  a  thickening 
and  peculiar  organization  of  the  sub-mucous  tissue  ;  it  is 
nearly  opposite,  but  a  little  anterior  to  the  third  or  middle 
lobe  of  the  prostate  gland.  The  trigone  is  the  most  sensi- 
ble and  vascular  part  of  the  bladder ;  posterior  to  the  tri- 
gone the  bladder  is  frequently,  particularly  in  old  subjects, 
dilated  into  a  sort  of  pouch.  In  the  female  the  trigone  is 
smaller,  but  broader  in  proportion  than  in  the  male,  and 
the  uvula  is  less  distinct. 

[There  is  one  feet  in  reference  to  the  bladder,  as  often  found  on 
post  mortem  examination,  which  should  be  borne  in  mind,  this  is  a 
remarkable  contraction  of  the  bladder,  from  having  been  empty  be- 
fore death,  the  cavity  being  scarcely  large  enough  to  hold  a  couple  of 
ounces  of  fluid,  and  the  muscular  coat  appearing  very  thick  and  dis- 
tinct, and  the  whole  organ  is  almost  concealed  under  the  arch  of  the 
pubis.  This  is  to  be  particularly  distinguished  from  the  contraction 
which  depends  upon  a  morbid  condition,  in  which  case  there  will  be 
other  evidences  of  disease.] 


21  DUBLIN    DISSECTOR. 

The  bladder  is  occasionally  found  in  a  diseased  state,  in- 
flammation of  it  (cystitis)  may  be  general  or  confined  to 
one  particular  part ;  the  portio'n  which  is  most  frequently 
so  affected  is  that  near  the  neck,  and  commonly  arises  from 
the  presence  of  a  rough  stone  ;  from  the  naturally  pale  ap- 
pearance of  the  mucous  membrane  in  the  dead  body,  any 
crowding  of  vessels  containing  arterial  blood  which  takes 
place  in  inflammation  makes  this  state  of  parts  easy  of  de- 
tection ;  and  this  is  the  case  in  chronic  inflammation  or  ca- 
tarrh of  the  bladder :  if  the  inflammation  be  violent,  the 
muscular  coat  may  become  engaged,  and  abscesses  and  ul- 
cers are  not  unfrequently  the  consequence  ;  they  sometimes 
proceed  so  far  as  to  destroy  a  portion  of  the  bladder,  and 
form  communications  between  it  and  the  neighbouring  vis- 
cera ;  with  the  rectum  in  the  male,  and  vagina  in  the  fe- 
male ;  they  have  also  been  known  to  open  into  the  cavity 
of  the  abdomen,  producing  peritonitis  and  death  from  ex- 
travasation of  urine  ;  abscesses  about  the  neck  of  the  blad- 
der are  generally  found  as  a  consequence  of  the  operation 
of  lithotomy  or  of  fatal  retention  of  urine,  or  diseased 
prostate  gland. 

[Inflammation  of  the  bladder  is  sometimes  caused,  from  the  urino 
being  retained  too  long.  Inflammation  may  terminate  in  resolution 
suppuration,  or  gangrene,  which  last  is  very  rare.  We  sometimes 
find  a  softening  of  the  mucous  membrane,  sometimes  also  hypertro- 
phy of  the  tunics,  but  more  particularly  of  the  muscular  coat,  and 
this  generally  arises  from  some  obstruction  about  the  neck  of  the 
bladder  or  in  the  urethra,  which  prevents  the  ready  discharge  of  the 
urine.] 

Calculi  are  not  uncommonly  formed  in  the  bladder : 
their  formation  is  confined  to  no  particular  period  of  life  ; 
they  are  found  in  very  young  children  and  in  persons  of 
middle  and  advanced  age  ;  they  are  very  seldom  met  with 
in  females,  as  the  size  of  the  urethra  in  that  sex  allows  them 
to  be  discharged  before  they  become  large,  probably  also 
the  tendency  to  their  formation  is  not  so  strong  in  females. 
The  stones  which  are  found  in  the  bladder  are  either  origi- 
nally formed  in  the  kidneys,  and  pass  through  the  ureters 
into  the  bladder,  or  they  are  at  first  formed  in  the  bladder 
itself.  Calculi  lie  either  loosely  in  the  cavity  of  the  blad- 
der, or  are  confined  to  some  fixed  situation  from  particular 
circumstances ;  when  they  are  of  a  small  size,  they  are 
sometimes  lodged  in  pouches,  formed  by  the  protrusion  of 
the  mucous  coat  of  the  bladder,  between  the  fasciculi  of 
its  muscular  fibres.  Urinary  calculi  have  sometimes  a 
smooth,  uniform  surface,  but  more  frequently  the  surface 
is  granulated  and  rough. 

The  urethra  is  the  next  division  of  the  urinary  organs  to 


DUBLIN    DISSECTOR.  215 

be  examined ;  as  this  canal,  however,  in  the  male,  is  the 
common  passage  for  the  urine  and  seminal  fluid,  or  as  it  is 
a  part  both  of  the  urinary  and  generative  organs,  we  shall 
postpone  the  description  of  it  until  we  have  considered  the 
latter. 

DISSECTION    OF   THE    ORGANS    OF    GENERATION    IN    THE    MALE. 

The  organs  of  generation  in  the  male  are  the  testicles 
and  their  appendices,  the  vesicular  seminales  ;  the  prostate 
and  anti-prostatic  glands,  (the  latter  have  been  already  ex- 
amined ;)  the  penis,  and  the  urethra.  We  shall  describe 
these  organs  in  the  following  order  :  1st,  the  testes,  with 
their  coverings ;  2nd,  the  vasa  deferentia  ;  3rd,  the  vesicula? 
seminales  ;  4th,  the  prostate  gland  ;  5th,  the  penis,  and  6th, 
the  urethra. 

1st.  THE  Tesl.es ;  these  two  glands  ore,  in  the  very  young 
foetus,  contained  in  the  abdomen  beneath  each  kidney  ;  a 
short  time,  however,  previous  to  birth,  they  descend  into 
that  situation  which  they  are  found  to  occupy  in  the  adult, 
and  are  surrounded  by  several  tunics,  viz.  the  scrotum,  dar- 
tos,  superficial  fascia,  tunica  communis,  tunica  vaginalis, 
and  tunica  albuginea. 

The  Scrotum  is  a  process  of  common  integument  con- 
tinued from  the  inner  side  of  each  thigh,  and  from  the  pe- 
rinseum  and  penis ;  it  is  generally  of  a  dark  brown  colour, 
thinly  covered  with  hair,  and  very  rugged,  being  thrown 
into  numerous  rugre,  it  is  so  thin  that  the  small  sub-cuta- 
neous veins  and  sebaceous  follicles  can  be  seen  through  it, 
these  latter  secrete  the  peculiar  perspirable  matter  of  this 
region,  the  prominent  hard  ridge  or  raphe  is  continued  from 
the  perina3iim  along  its  middle  line  as  far  as  the  penis. 
The  Dartos  is  the  cellular  tissue  immediately  subjacent  to 
the  skin,  it  usually  presents  a.  reddish  appearance,  a  num- 
ber of  small  vessels  being  distributed  through  it ;  its  tex- 
ture is  very  loose,  and  is  readily  distended  in  emphysema 
or  in  anasarca  ;  it  never  contains  any  fat  ;  it  is  somewhat 
more  dense  in  the  mesial  line  than  at  either  side.  The 
dartos  is  connected  to  the  rami  of  the  pubis  and  ischium 
of  each  side,  and  to  the  raphe  in  the  middle,  thence  it  as- 
cends a  short  way  between  the  testes  to  the  urethra,  and 
thus  assists  the  superficial  fascia  in  forming  the  septum 
scroll.  The  dartos  manifests  during  life  a  degree  of  con- 
tractility above  that  which  the  cellular  tissue  enjoys  in  any 
other  situation  ;  it  has  therefore  been  considered  by  some 
as  a  cutaneous  muscle ;  this  idea  is  most  probably  incor- 
rect, although  it  certainly  possesses  the  power  of  corruga- 
ting the  skin,  distinct  from  that  rolling  motion  of  the  tes- 
ticle produced  by  the  cremaster  muscle;  posteriorly  the 


216  DUBLIN    DISSECTOR. 

dartos  frequently  appears  to  derive  a  few  muscular  fibres 
from  the  sphincter  ani. 

[Meckel  suggested,  that  the  Dartos  was  the  transition  between 
muscle  and  cellular  tissue.  Cruveilhier  looks  upon  it,  as  being  the 
same  tissue  with  the  external  coat  of  the  vagina,  with  the  external 
coat  of  the  veins,  and  the  substance  of  the  nipple.  By  some  anato- 
mists the  Dartos  has  been  considered  an  expansion  of  the  guberna- 
culum  testis,  and  not  to  exist  in  the  scrotum,  until  after  the  descent 
of  the  testicle  ;  but  on  the  other  hand  it  has  been  found  in  the  scrotum 
of  the  fetus,  before  the  descent  of  the  testicle,  and  in  the  case  of  an 
adult,  in  whom  the  testicle  had  not  passed  down  through  the  ring, 
Cruveilhier  satisfied  himself  of  the  co-existence  of  the  gubernaculum 
and  the  dartos,  independently  of  each  other.] 

Beneath  the  dartos  is  the  superficial  fascia  of  the  scrotum, 
this  is  continued  from  that  of  the  abdomen  around  each 
spermatic  cord,  testicle,  and  epididymis ;  it  is  thin,  loose 
and  reticular,  and  becomes  continuous  with  the  fascia  of 
the  perinaeum  :  as  this  fascia  envelopes  the  cord  and  testis 
on  each  side,  it,  assisted  by  the  dartos,  forms  the  septum 
scroll,  and  so  retains  each  testicle  at  its  own  side.  The  tu- 
nica communis  is  composed  of  the  expanded  fibres  of  the 
crernaster  muscle  and  of  fine  connecting  cellular  mem- 
brane ;  this  tunic  surrounds  the  cord  and  testis  :  the  fibres 
of  the  cremaster  are  expanded  chiefly  on  the  forepart  and 
sides  of  the  testis.  The  tunica  vaginalis  was  originally,  that 
is,  in  foetal  life,  a  process  of  the  peritonaeum,  having  been 
prolonged  along  the  cord  and  around  the  testicle  as  the  lat- 
ter was  descending  from  the  abdomen  to  the  scrotum ;  at 
this  early  age,  the  tunica  vaginalis  in  the  scrotum  commu- 
nicated with  the  general  cavity  of  the  peritonaeum  by  a 
sort  of  canal  which  led  along  the  forepart  of  the  cord  from 
the  abdomen  to  the  scrotum :  this  canal,  however,  about 
the  period  of  birth  was  closed  by  the  adhesive  process,  and 
ever  afterwards  the  cavity  of  the  tunica  vaginalis  is  quite 
distinct  from  that  of  the  peritonaeum.*  The  tunica  vagi- 
nalis, therefore,  is  a  serous  membrane,  a  shut  sac,  suspend- 
ing, and  partly  enclosing  the  testicle,  and  also  reflected 
over  its  anterior  part  and  sides :  that  portion  of  it  which 
suspends  the  gland,  and  which  lines  the  scrotum,  may  be 
named  the  tunica  vaginalis  scroti ;  while  the  reflected  por- 
tion which  covers  the  sides  and  forepart  of  the  testicle  is 
the  tunica  vaginalis  testis.  This  membrane  is  so  loosely 
connected  to  the  scrotum  that  it  can  be  detached  from  it 
with  little  force  ;  it  is  thence  reflected  on  the  sides  and  fore- 
part of  the  epididymis  and  testis,  it  also  ascends  a  short 

*  When  this  canal  is  not  thus  closed,  a  hernia  usually  occurs,  which  is  named 
"  congenital  inguinal  hernia." 


DUBLIN    DISSECTOR.  217 

distance  on  the  forepart  of  the  cord ;  the  posterior  part  of 
the  epididymis  is  altogether  uncovered  by  it :  as  it  is  con- 
tinued from  the  epididymis  to  the  testicle  it  passes  in  be- 
tween these  organs,  particularly  on  their  outer  side,  so  as 
to  form  a  sort  of  pouch  between  them.  Both  the  testicle 
and  epididymis  are  in  reality  behind  this  serous  mem- 
brane, and  nothing  is  contained  within  its  cavity  except 
the  serous  fluid,  which  lubricates  its  opposed  surfaces,  and 
which  facilitates  that  gliding  motion  which  the  testicle  un- 
dergoes in  the  scrotum. 

[The  cavity  of  the  tunica  vaginalis  will  receive  from  one  to  two 
ounces  of  fluid  without  distention,  but  when  distended,  as  in  hydrocele, 
it  sometimes  contains  even  quarts.] 

When  the  anterior  part  of  the  tunica  vaginalis  is  divided, 
we  see  its  internal  surface  smooth  and  polished,  and  shin- 
ing through  its  reflected  layer  which  covers  the  testis,  we 
can  discern  the  next  tunic  of  this  gland,  tunica  albuginea : 
this  is  a  dense  fibrous  membrane  ;  it  forms  the  proper  cap- 
sule of  the  gland,  adheres  to  it,  preserves  its  peculiar  form, 
and  sends  several  processes  or  septa  into  the  testicle,  which 
will  be  seen  when  the  body  of  the  latter  shall  have  been 
opened  ;  it  has  no  connexion  to  the  epididymis :  it  is  dim- 
cult  to  dissect  otf  the  reflected  layer  of  the  serous  mem- 
brane, or  the  tunica  vaginalis  testis  from  the  tunica  albu- 
ginea,  they  are  so  intimately  united ;  through  the  latter 
several  blood  vessels  can  be  distinctly  seen  ;  indeed  the  al- 
buginea  can  easily  be  separated  into  two  lamina?,  the  ex- 
ternal strong  and  "fibrous,  the  internal  soft  and  vascular, 
formed  by  the  ramifications  of  the  spermatic  artery.  Each 
testicle  is  of  an  oval  form,  flattened  on  each  side,  also  a  little 
on  the  back  part  beneath  the  epididymis ;  it  is  suspended 
rather  obliquely,  the  superior  extremity  being  directed  for- 
wards and  outwards,  the  inferior  backwards  and  inwards. 

[The  testicles  are  not  suspended  at  the  same  level,  that  of  the  left 
being  lower  down  than  that  of  the  right  side,  for  two  reasons,  says 
S  r  A.  Cooper,  the  one  to  allow  of  the  disposition  of  the  p?n;s  to  one 
side  of  the  median  line,  the  other  to  ailow  of  tho  ore  testicle  gliding 
upon  and  above  the  other,  in  the  close  adduction  and  crossing  of  the 
thighs.  It  is  said  that  there  is  usually  a  difference  in  the  size  of  the 
testicles,  but  if  any,  it  must  be  but  slight  as  some  anatomists  jjive  the 
difference  in  favor  of  the  left,  and  others  in  favor  of  the  right.  In 
some  cases  as  stated  there  is  but  one  testicle,  while  in  others  there 
are  more  than  two.  Those  cases  reported  as  belonging  to  the  former 
class,  are  almost  always  cases,  in  which  one  of  the  testicles  has  not 
descended  into  the  scrotum.  Cruveilhier  however  dissected  a  subject 
in  which  he  found  but  one  testicle.  It  does  not  appear  to  be  satis, 
faclorily  proved,  that  there  are  ever  more  than  two  of  the  organs ; 
the  apparent  instances,  have  been  in  consequence  of  the  presence  of 


218  DUBLIN    DISSECTOR. 

tumours  of  some  kind.  I  have  seen  two  of  these  cases,  in  which  the 
individuals  supposed  that  they  had  three  testicles,  but  on  examination, 
the  third  body  proved  to  be  morbid,  in  one  case  it  was  a  small  hyda- 
tid.  The  situation  of  the  testicles,  in  foetal  life,  is  verv  different  from 
that  in  which  they  are  usually  found  after  birth.  At  the  middle  of 
the  third  month  of  utero-  gestation,  the  cavity  of  the  abdomen,  com. 
municates  on  either  side,  with  the  cavities  of  the  scrotum  or  sacculi 
testium,  by  short  oblique  canals,  which  at  this  period  correspond  to 
what  in  the  subsequent  development  of  the  parts,  constitute  the  ab- 
dominal rings  and  inguinal  canal.  At  this  period  the  peritonaeum 
lining  the  abdomen,  is  continued  down  into  the  sacculi,forming  small 
pouches.  The  testicle  itself  is  in  the  cavity  of  the  abdomen,  on  the 
psoas  muscle  below  the  inferior  extremity  of  the  kidney ;  and  is  poste- 
rior to  the  peritonaeum  like  all  the  abdominal  viscera,  that  membrane 
however,  is  reflected  over  the  sides,  and  fore  part  of  the  testis,  from  the 
lower  end  of  which  proceeds  a  small  ligament,  the  gubernaculum  testis 
which  terminates  at  the  upper  and  inner  part  of  the  scrotum,  being 
also  behind  the  peritonaeum.  At  this  time  the  spermatic  vessels  are 
quite  short,  and  descend  a  little  obliquely  to  the  posterior  border  of 
the  testicle,  while  the  vas  deferens  passes  obliquely  over  the  iliac 
vessels,  into  the  pelvis.  This  original  position  of  the  testis  and  its 
subsequent  descent,  explain  the  remarkable  length  of  the  spermatic 
vessels  in  the  adult. 

Being  thus  placed  the  testicle  gradually  descends  towards  the 
scrotum,  as  is  said  by  some,  from  the  contraction  of  the  guberna- 
culum, until  usually  in  the  course  of  the  seventh  or  eighth  month,  of 
utero-gestation  it  is  lodged  in  the  sacculus  testis;  having  fairly  reached 
this  cavity  the  passage  from  the  abdomen  contracts  and  becomes 
completely  obliterated,  so  that  there  is  no  longer  any  communication 
between  the  several  cavities,  and  the  serous  membrane  of  the  pas- 
sage is  converted  into  cellular  tissue,  which  is  sometimes  the  seat  of 
hydrocele  of  the  cord.  The  closure  of  the  passage  after  the  descent 
of  the  testicle,  does  not  always  take  place,  and  then  a  portion  of  in- 
testine may  descend  with  the  testicle,  constituting  congenital  hernia, 
or  fluid  may  pass  down  into  the  sacculus,  which  is  called  congenital 
hydrocele.  The  testicle  while  in  the  cavity  of  the  abdomen  has  a 
proper  and  complete  fibrous  covering,  the  tunica  albuginea ;  after  it 
gets  into  the  sacculus,  the  peritonaeum  which  invested  it  in  the  abdo- 
men, becomes  the  tunica  vaginahs  testis,  while  the  original  serous 
lining  of  the  scrotum,  is  the  tunica  vaginalis  scroti,  and  the  two  to- 
gether, constitute  the  tunica  vaginalis  communis,  exterior  and  pos- 
terior to  the  cavity  of  which  is  the  testicle,  and  within  which  cavity, 
true  hydrocele  and  hematocele  take  place.  Both  testicles  do  not 
always  descend,  one  is  sometimes  retained  in  the  abdomen  or  be- 
comes entangled  in  the  passage,  and  may  in  after  life  be  confounded 
with  concealed  inguinal  hernia. 

Weight  and  Measurements  of  the  Testicle.  These  differ  much  in 
different  individuals  ;  on  the  average  they  are  from  twenty-two  to 
twenty-four  lines  in  length,  from  twelve  to  eighteen  lines  broad,  and 
from  seven  to  eight  lines  thick.  Their  average  weight  is  about  six 
drachms,  the  epididyrnis  ranging  from  two  to  three  scruples ;  Sir  A. 
Cooper  gives  the  weight  of  the  testicle  as  high  as  one  ounce.  The 


DUBLIN    DISSECTOR.  219 

color  of  the  organ  is  a  greyish  white  depending  upon  the  color  of  its 

tunics.] 

Bent  like  an  arch,  along  the  posterior  surface  of  each 
testicle,  is  the  epididymis,  long  and  narrow,  large  above, 
(globus  major,)  narrow  in  the  middle,  (body,)  and  again 
enlarged  below,  (globus  minor,)  attached  to  the  testicle 
above  by  vessels,  and  in  the  rest  of  its  extent  by  the  re- 
flected layer  of  the  tunica  vaginalis,  closely  on  the  inter- 
nal, but  very  loosely  on  the  external  or  femoral  side  ;  from 
its  inferior  extremity  the  vas  deferens  proceeds,  and  thence 
ascends  along  its  internal  side.  Divide  the  tunica  albugi- 
nea  anteriorly,  and  we  observe  the  testicle  to  be  composed 
of  a  soft  greyish  or  yellowish  pulpy  substance,  which, 
when  opened  out  a  little,  and  floated  in  water,  is  found  to 
consist  of  numerous  fine  tortuous  shreds  or  vessels  of  deli- 
cate texture,  loosely  connected  to  each  other ;  some  are  of 
considerable  length,  and  with  a  little  care  may  be  drawn 
out  of  the  gland  to  the  extent  of  two  or  three  feet ;  they 
are  placed  in  packets  or  fasciculi,  which  are  separated 
from  each  other  by  fibrous  bands  or  septa,  which  are  de- 
rived from  the  tunica  albuginea,  and  which  may  now  be 
seen  to  pass  in  considerable  numbers  through  the  gland 
towards  the  back  part,  where  they  join  the  corpus  Highmor- 
ianum;  this  name  is  applied  to  a  long  fold  or  process  of 
the  tunica  albuginea,  which  projects  into  the  back  part  of 
the  gland  ;  it  consists  of  two  laminae,  between  which  the 
vessels  and  nerves  of  the  testicle  are  enclosed ;  this  pro- 
cess is  broader  above  than  below,  is  perforated  in  the  for- 
mer situation  by  the  excretory  ducts  of  the  testicle ;  to  its 
anterior  border  and  sides  are  attached  the  sepimenta  or 
processes  of  the  tunica  albuginea  before  mentioned.  This 
process  is  also  more  properly  denominated  the  "medias- 
tinum testis"  as  it  plainly  consists  of  two  laminae,  and  con- 
tains in  the  interspace  the  excretory  portion  of  the  gland. 
From  the  several  collections  of  small  tubes,  which  are  dis- 
posed between  these  bands  or  septa,  about  twelve  or  twenty 
larger  vessels  may  be  seen  to  proceed  in  parallel  lines  to- 
wards the  back  part  of  the  gland  ;  these  are  the  tubuli  recti ; 
they  enter  the  mediastinum,  and  if  one  lamina  of  this  pro- 
cess be  raised  off  they  will  be  seen  entangled  with  each 
other,  and  with  the  vessels  and  nerves  of  the  gland ;  this 
structure  receives  the  name  of  Rete  Testis,  it  is  placed  near 
the  posterior  part  of  the  gland,  between  the  lamina?  of  the 
mediastinum  or  the  corpus  Highmorianum ;  from  the  up- 
per part  of  this  tissue  five  or  six  tortuous  vessels  ascend 
obliquely  backwards,  pierce  the  tunica  albuginea,  and  ar- 
rive at  the  head  of  the  epididymis ;  here  they  increase  in 
size,  and  become  coiled  or  convoluted ;  these  are  the  vasa 


220  DUBLIN    DISSECTOR. 

deferentia  or  coni  vasculosi ;  they  all  terminate  in  the  head  or 
globus  major  of  the  epididymis,  and  unite  into  one  small 
duct  (the  vas  deferens),  which  is  twisted  and  coiled  over 
and  over  again  in  a  most  extraordinary  and  peculiar  man- 
ner. The  body  and  globus  minor  of  the  epididymis  are 
solely  composed  of  this  convoluted  vessel,  which  by  care 
may  be  unravelled  to  a  great  extent :  the  convolutions  of 
this  tube,  of  which  the  epididymis  thus  consists,  are  con- 
nected to  each  other  by  fine  cellular  tissue  and  by  the  re- 
flected tunica  vaginalis;  the  epididymis  has  no  fibrous 
capsule  like  the  testis  ;  from  its  lower  extremity  the  vas  de- 
ferens at  length  escapes,  and  increasing  in  size  and  density, 
this  duct  bends  upwards  along  the  inner  side  of  the  epidi- 
dymis, and  a  little  above  the  head  of  the  latter  it  becomes 
connected  to  the  spermatic  vessels  and  cremaster  muscle ; 
with  these  it  continues  its  course  obliquely  upwards  and 
outwards  along  the  inguinal  channel,  and  through  the  in- 
ternal abdominal  ring :  it  here  separates  from  the  sper- 
matic vessels,  the  latter  ascending  towards  the  spine,  while 
the  vas  deferens  passes  backwards,  inwards,  and  down- 
wards, enclosed  in  the  lateral  fold  of  peritonaeum,  which 
conducts  it  to  the  bladder,  along  the  side  and  inferior  fun- 
dus  of  which  it  runs  internal  to  the  vesicuia  seminalis,  and 
converging  to  its  fellow :  at  the  base  of  the  prostate  gland 
each  vas  deferens  joins  the  duct  of  the  corresponding  vesi- 
cula,  and  the  union  of  these  forms  the  ductus  ejaculatorius 
communis  which  runs  through  the  prostate  obliquely  for- 
wards and  inwards,  and  opens  into  the  prostatic  portion  of 
the  urethra  on  the  side  of  the  verumontanum,  [anteriorly, 
being  from  eight  to  ten  lines  in  length.]  While  the  vas 
deferens  is  contained  in  the  spermatic  cord,  it  lies  posterior 
to  the  spermatic  arteries  and  veins,  and  to  the  cremaster 
muscle;  as  it  passes  through  the  internal  ring  it  hooks 
round  the  outer  side  of  the  epigastric  artery,  being  separa- 
ted from  it  by  the  spermatic  artery  alone  ;  the  vas  deferens 
next  passes  over  the  psoas  and  iliac  muscles,  the  external 
iliac  artery  and  vein;  it  then  bends  over  the  obliterated 
hypogastric  artery  and  descends  internal  to  it ;  and  in  the 
same  manner  it  next  crosses  over  the  ureter,  so  as  to  lie  at 
first  anterior  to  that  tube,  or  between  it  and  the  bladder, 
and  then  to  descend  along  its  internal  side ;  the  vas  defe- 
rens then  runs  between  the  bladder  and  rectum,  near  to  its 
fellow,  and  internal  to  the  vesicula  seminalis,  as  far  as  the 
prostate  gland,  which  it  perforates  in  the  direction  before 
mentioned.  This  vessel  has  a  peculiar  hard  wiry  feel  like 
whip-cord  :  its  calibre  is  small ;  its  coats  are  two  in  num- 
ber, an  internal  mucous,  and  an  external,  very  thick,  firm, 
and  white  like  cartilage.  Between  the  vesiculse  each  vas 


DUBLIN    DISSECTOR.  221 

deferens  is  flattened,  enlarged,  and  often  covuluted ;  when 
it  enters  the  prostate  it  again  contracts,  and  its  firm  exter- 
nal tunic  ceases.  In  some  a  second  duct  will  be  found  to 
leave  the  testis  and  to  run  for  some  distance  parallel  to  the 
vas  deferens,  which  in  some  cases  it  will  join,  while  in 
others  it  will  be  found  to  end  in  a  cul  de  sac.  The  spermatic 
cord  extends  from  the  epididymis  to  the  internal  abdominal 
ring;  it  consists  of  the  vas  deferens,  spermatic  artery, 
veins,  nerves,  and  lymphatics ;  this  fasciculus  of  vessels  is 
covered  by  loose  cellular  membrane,  and  by  the  cremaster 
muscle :  beneath  the  latter  the  vessels  of  the  cord  will  be 
found  joined  together  by  a  fine  but  tolerably  dense  mem- 
brane, named  the  tunica  vaginalis  of  the  cord;  this  mem- 
brane is  the  remains  of  that  portion  of  peritonaeum  which 
in  the  foetus  accompanied  the  spermatic  vessels  of  the  scro- 
tum, and  which  after  birth  lost  its  serous  characters,  and 
became  converted  into  condensed  cellular  membrane ;  this 
covering  is  strengthened  by  that  prolongation  of  the  fascia 
transversalis  which  is  continued  from  the  internal  abdomi- 
nal ring  along  the  spermatic  vessels.  The  spermatic  artery 
arises  from  the  abdominal  aorta  below  the  renal  artery, 
and  not  unfrequently  from  the  latter ;  it  descends  along  the 
psoas  muscle  [over  the  ureter,]  passes  through  the  internal 
abdominal  ring  on  the  outer  side  of  the  epigastric  artery  ; 
it  then  enters  the  spermatic  cord,  and  is  conducted  to  the 
back  part  of  the  testicle ;  it  divides  into  several  branches 
which  enter  the  rete  testis ;  these  subdivide  minutely  as 
they  proceed  into  the  substance  of  the  testicle,  in  which 
they  terminate  in  the  commencement  of  the  tubuli  semini- 
feri  and  of  the  spermatic  veins.  The  last  named  vessels 
leave  the  rete  testis,  twine  around  the  arteries,  and  then  as- 
cend in  the  spermatic  cord ;  a  little  above  the  testicle  these 
vessels  become  very  tortuous,  and  form  a  plexus,  which  is 
named  the  Corpus  Pampiniforrne  :  the  spermatic  veins  then 
accompany  the  spermatic  artery  through  the  inguinal  canal 
and  along  the  psoas  muscle  towards  the  spine :  the  sper- 
matic vein  on  the  right  side  generally  ends  in  the  inferior 
cava  near  the  entrance  of  the  right  renal  vein ;  the  sper- 
matic vein  on  the  left  side  frequently  ends  in  the  left  renal 
vein. 

[The  left,  spermatic  vein,  most  commonly  ends  in  the  left  renal 
vein  and  this  will  explain  the  fact,  that  varicocele  most  commonly 
occurs  on  the  left  side.  The  left  spermatic  vein  terminates  in  the 
left  renal  vein,  nearly  at  a  right  angle,  while  the  latter  terminates  in 
the  abdominal  vena  cava,  also  at  nearly  a  right  angle,  hence  the  re. 
turn  of  the  blood  from  the  left  testicle  must  necessarily  be  retarded, 
having  to  describe  these  two  angles,  while  the  blood  from  the  right 
testicle  will  readily  flow  into  the  vena  cava  into  which  the  right 


222  DUBLIN    DISSECTOR. 

spermatic  vein  empties  very  obliquely.  The  spermatic  veins  in  vari- 
cocele,  are  sometimes  so  much  distended,  as  entirely  to  destroy  the 
usefulness  of  the  valves  and  then  if  the  cord  be  divided  below  the  ex- 
ternal abdominal  ring,  a  direct  hemorrhage  from  the  vena  cava  will 
ensue.  I  have  seen  a  cat--e  of  this  kind  in  a  man  twenty-seven  years 
of  age,  who  was  castrated  on  account  of  a  varicecele  of  twenty  years 
standing,  in  which  the  hemorrhage  from  above  was  profuse,  the  di- 
lated veins  being  nearly  as  large,  as  the  end  of  the  little  ringer.  Be- 
sides the  true  spermatic  artery,  there  are  two  other  arteries  connected 
with  the  cord,  the  deferential,  and  the  cremasteric. 

The  deferential  artery,  is  a  branch  of  the  vesicle,  one  of  the  branches 
of  the  internal  iliac, it  comes  off  in  the  pelvis,  and  applies  itself  to  the 
vas  deferens,  which  it  follows  up  over  the  brirn  of  the  pelvis,  and  the 
external  iliac  vessels;  at  the  out  side  of  the  epigastric  it  passes  through 
the  internal  ring  into  the  inguinal  canal,  and  thence  passes  down  to 
the  testicle  still  following  the  vas  deferens.  The  cremasteric  artery  is 
a  branch  of  the  epigastric,  and  is  so  called,  from  being  distributed 
principally  in  connexion  with  the  cremaster  muscle.  I  have  found 
the  deferential  artery  on  both  sides,  quite  as  large  as  the  spermatic.] 

The  nerves  of  the  testicle  are  derived  chiefly  from  the 
spermatic  plexus,  which  is  formed  by  the  union  of  branch- 
es from  the  lumbar  ganglions  of  the  sympathetic,  with  fil- 
aments from  the  splanchnic  nerves  and  from  the  renal 
plexus ;  the  cremaster  muscle  is  also  supplied  by  branches 
from  the  lumbar  plexus  of  spinal  nerves,  hence  this  muscle 
is,  to  a  certain  extent,  voluntary. 

The  Vesicula  seminales  are  two  in  number ;  they  are  situ- 
ated on  the  inferior  surface  of  the  bladder  behind  and  above 
the  prostate  gland,  on  the  outer  side  of  the  vasa  dcferentia, 
and  anterior  to  the  rectum. 

[These  organs  are  in  fact,  placed  in  a  kind  of  fissure  formed  by  the 
apposrtion  of  two  cylindroidal  bodies,  the  rectum  and  the  bladder,  and 
are  imbedded  in  a  mass  of  dense  cellular  tissue  traversed  by  veins, 
so  that  they  are  not  brought  into  view  until  this  substance  is  dissected 
away.  In  these  veins,  I  have  several  times  found  the  phlebolites  or 
vein  stones.] 

Each  is  of  an  oval  figure. 

[In  length  they  are  from  two  inches  to  two  and  a  half,  in  breadth, 
half  an  inch,  and  in  thickness  two  to  four  lines;  their  color  is  a  greyish 
white  depending  upon  the  external  tunic,  their  volume  is  greater  in 
the  middle  aged  than  in  the  young  or  old  subject,  they  are  sometimes 
very  small,  and  in  some  cases  one  is  wanting.] 

The  superior  and  posterior  extremity  is  round,  and  in 
contact  with  the  ureter ;  the  anterior  extremity  is  narrow, 
connected  to  the  prostate  gland,  and  ends  in  a  small  duct, 
[a  line  and  a  half  in  length]  which  joins  the  vas  deferens ; 
the  union  of  these  forming  the  common  seminal  or  ejacula- 
tory  duct,  which  latter  passes  obliquely  forwards  and  in- 


DUBLIN    DISSECTOR.  223 

wards  through  the  prostate  gland,  and  opens  into  the  ure- 
thra by  the  side  of  the  verumontanum, 

[Anteriorly, being  from  eight  to  ten  lines  in  length,  and  running 
parallel  with  its  fellow  under  the  urethra.] 

Although  the  vesiculse  look  like  a  congeries  of  cells,  yet 
"by  dissection  they  may  be  unravelled,  so  as  to  appear  as 
one  continued  tube  convoluted  or  coiled  very  much,  the 
different  coils  communicating  with  each  other. 

[When  the  vesicles  are  thus  unravelled,  their  length  is  from  four  to 
eight  inches.  Cruveilhier  has  seen  one  a  foot  iu  length.] 

These  organs  are  covered  by  a  dense  fascia,  which  is 
continued  from  that  covering  the  prostate  gland.  Each 
vesicula  consists  of  two  tunics,  viz.  mucous  membrane  in- 
ternally, and  peculiar  grey  substance  externally,  somewhat 
similar  to,  but  softer  than  the  outer  coat  of  the  vas  deferens. 
The  vas  deferens  communicates  more  freely  with  the  cor- 
responding vesicula  than  the  latter  does  with  the  urethra, 
hence  air  or  fluid  injected  into  the  vas  deferens  will  gener- 
ally distend  the  vesicula  seminalis  of  the  same  side  before 
it  escapes  into  the  urethra.  These  organs  are  generally 
believed  to  contribute  some  additional  secretion  to  the  semi- 
nal fluid,  rather  than  to  serve  as  reservoirs  for  the  latter ; 
their  exact  use,  however,  is  not  well  known ;  they  are 
wanting  in  many  animals. 

The  Prostate  gland  is  situated  at  the  anterior  and  inferior 
part  of  the  pelvis,  behind  the  triangular  ligament,  and  in 
front  of  the  rectum,  to  which  it  is  connected  by  cellular 
membrane;  it  surrounds  the  neck  of  the  bladder,  and 
is  attached  by  the  anterior  ligaments  of  this  organ  to  the 
lower  edge  of  the  symphysis  pubis,  from  which  it  is  about 
three-fourths  of  an  inch  distant.  The  prostate  gland  is 
somewhat  heart-shaped,  or  triangular  ;  it  is  also  compared 
to  a  chestnut ;  the  base  or  larger  extremity  is  posterior,  and 
connected  to  the  vesiculse  seminales ;  the  apex  is  anterior, 
and  extends  to  within  a  short  distance  of  the  triangular 
ligament ;  the  neck  of  the  bladder,  and  about  an  inch  of  the 
urethra  run  through  its  substance,  but  a  small  portion  of  it 
lies  superior  to  the  neck  of  the  bladder  and  urethra;  this 
part  is  convex,  and  is  covered  by  the  dorsal  veins  of  the 
penis,  and  by  the  anterior  ligaments  of  the  bladder ;  the 
inferior  or  posterior  surface  of  the  gland  is  almost  flat,  a 
slight  groove  is  generally  observable  on  it,  extending  along 
the  mesial  line ;  this  surface  is  attached  to  the  forepart  of 
the  rectum,  and  may  be  felt  distinctly  either  in  the  living 
or  in  the  dead  subject  by  the  finger  introduced  into  the  in- 
testine about  two  inches  and  a  half  above  the  anus;  the 
sides  of  the  gland  are  smooth  and  round,  and  are  covered 


224  DUBLIN    DISSECTOR. 

by  a  strong  fascia,  by  several  veins,  and  by  the  levatores 
ani  muscles.  In  the  base  or  posterior  end  is  a  notch  for 
the  entrance  of  the  common  ejaculatory  ducts ;  this  notch, 
together  with  the  groove  on  the  posterior  surface,  and  the 
passage  of  the  urethra  above  this,  have  caused  this  gland 
to  be  described  as  consisting  of  two  lateral  portions,  called 
the  right  and  left  lateral  lobes ;  these  are  connected  to  each 
other  posteriorly  by  a  small  transverse  process,  called  the 
middle  lobe;  this  may  be  seen  by  detaching  the  vesiculse 
seminales,  and  vasa  deferentia  from  the  bladder,  and  leav- 
ing them  suspended  by  their  common  ducts,  the  middle 
lobe  of  the  prostate  will  then  be  seen  to  pass  from  one 
lateral  lobe  to  the  other,  and  to  be  closely  connected  to  the 
mucous  membrane  of  the  bladder. 

[The  prostate  gland  weighs  about  five  drachms,  its  length  is  from 
eighteen  to  twenty-one  lines,  its  breadth  from  fifteen  to  eighteen  lines, 
and  its  thickness  from  nine  to  twelve  lines.] 

It  has  also  a  firm  resisting  feel,  is  of  a  greyish  colour, 
and  appears  to  possess  a  very  compact  structure;  this, 
however,  is  chiefly  owing  to  the  strong  fascia  which  in- 
vests it,  and  which  forms  its  capsule  :  the  capsule  has  been 
already  described  as  being  partly  derived  from  the  poste- 
rior layer  of  the  triangular  ligament,  which  expands  on  the 
sides  and  inferior  surface  of  the  gland,  and  partly  from  the 
reflection  of  the  pelvic  fascia  from  the  pubes  called  the 
anterior  ligaments  of  the  bladder.  Next  continue  the  in- 
cision which  was  made  in  the  forepart  of  the  bladder, 
through  the  upper  part  of  the  prostate,  so  as  to  lay  open 
the  urethra,  we  shall  perceive  how  this  gland  surrounds  the 
canal,  also  the  greater  thickness  of  its  lateral  portions. 
The  prostate  gland  consists  of  several  follicles  or  acini 
closely  connected  to  each  other,  and  covered  externally  by 
the  capsule,  and  internally  by  the  mucous  membrane  ;  these 
follicles  open  by  several  small  ducts,  ten  or  twelve,  on  the 
lower  surface  of  the  urethra,  on  either  side  of  the  verumon- 
tanum ;  some  small  ducts  also  open  on  the  upper  surface 
of  the  canal. 

[This  organ  is  divided  in  the  lateral  and  bilateral  operations  for 
stone,  and  is  easily  torn  after  being  once  cut  into.] 

The  Penis  is  covered  by  the  common  integuments,  and 
by  the  superficial  fascia ;  the  skin  is  thin  and  loose,  it  is 
continued  from  that  of  the  abdomen  and  scrotum  around 
this  organ,  and  extends  some  way  beyond  it  in  the  form  of 
a  loose  fold,  the  prepuce;  from  the  extremity  of  this  process 
the  skin  is  reflected  inwards  as  far  as  the  corona  glandis, 
where  ft  becomes  very  thin ;  it  is  thence  continued  over 
the  glans  penis  to  the  orifice  of  the  urethra,  where  it  is 


DUBLIN    DISSECTOR.  225 

continuous  with  the  lining  membrane  of  the  urethra ;  infe- 
rior to  this  opening  it  forms  a  fold,  the  fraenum  preputii ; 
the  prepuce,  therefore,  is  only  a  fold  of  the  common  inte- 
gument, the  sides  of  which  are  connected  together  by  very 
loose  reticular  tissue ;  this  fold  is  expanded  when  the  pre- 
puce is  drawn  back,  or  when  the  penis  becomes  distended ; 
the  inner  side  of  the  prepuce  is  of  more  delicate  texture 
than  the  external,  and  that  portion  of  it  which  is  continued 
over  the  glans  is  still  more  delicate  than  either.  Beneath 
the  skin,  around  the  corona  glandis,  are  a  number  of  small 
sebaceous  glands,  glanduloe  odorifene,  or  Tysoni, 

[Which  secrete  a  white  oleaginous  substance  the  smegma  preputii, 
which  accumulates  from  want  of  cleanliness  and  becoming  acrid, 
causes  excoriations,  which  may  be  mistaken  for  syphilitic  sores. 
The  prepuce  is  sometimes  too  short  and  instead  of  covering  the 
glans  penis  is  contracted  around  the  neck  of  the  organ  behind  the 
corona  glandis,  this  is  called  paraphymosis  ;  on  the  other  hand  it 
sometimes  covers  the  glans  but  cannot  be  drawn  back  so  as  to  ex- 
pose it,  and  this  is  phimosis,  for  which  circumcision  is  performed.  It 
is  said  that  those  who  have  the  prepuce  long  are  more  apt  to  con- 
tract the  venereal  disease  than  those  in  whom  it  is  shorter.] 

The  superficial  fascia  which  covers  the  penis  is  continued 
from  that  of  the  abdomen,  and  extends  around  the  penis  as 
far  as  the  corona  glandis ;  it  is  thick  and  strong  posteriorly, 
where  it  is  reflected  from  the  linea  alba  on  the  penis,  so  as 
to  form  the  superficial  suspensory  ligament  of  the  latter ; 
anteriorly  it  is  loose  and  delicate.  Beneath  these  coverings 
the  penis  is  found  to  consist  of  two  long  cylindrical  bodies, 
termed  the  crura  or  corpora  cavernosa  penis ;  each  of  these 
is  composed  of  a  strong,  elastic,  tendinous  and  fibrous  sub- 
stance [which  is  called  the  theca,]  forming  a  sort  of  tube, 
which  is  filled  with  a  soft  cellular  or  erectile  tissue,  through 
which  a  large  artery,  and  many  small  tortuous  veins,  run 
from  one  end  to  the  other.  Each  crus  penis  commences 
narrow  in  front  of  the  tuber  ischii,  and  adheres  to  the  rami 
of  the  ischium  and  pubis,  as  far  forwards  as  the  symphy- 
sis ;  anterior  to  this  the  crura  become  inseparably  united, 
and  continue  so  as  far  as  the  corona  glandis;  here  each 
crus  ends  in  an  obtuse  point,  over  which  the  glans  penis, 
which  is  the  expanded  extremity  of  the  corpus  spongiosum 
urethrse,  is  folded ;  the  two  crura  are  attached  to  the  sym- 
physis  pubis  by  the  true  suspensory  ligament,  which  is  very 
strong,  and  of  a  triangular  figure ;  it  arises  from  the  sym- 
physis,  and  is  inserted  into  each  crus ;  it  consists  of  two 
laminae,  between  which  the  dorsal  vessels  and  nerves  of  the 
penis  pass.  The  crura  penis  are  separated  from  each  other 
by  an  imperfect  tendinous  septum,  composed  of  parallel 


226  DUBLIN    DISSECTOR. 

fibres,  with  such  intervals  between  them  that  the  cavity  of 
one  crus  communicates  with,  and  can  be  injected  from  that 
of  the  other ;  this  septum  is  named  pectiniforme*  The  cru- 
ra  penis  are  somewhat  conical,  the  apex  of  each  being  at- 
tached to  the  ischium  and  pubis,  the  base  supporting  the 
glans;  they  are  round  externally,  flattened  towards  each 
other ;  a  wide  and  deep  groove  exists  between  them  infe- 
riorly,  which  contains  the  urethra,  and  a  more  superficial 
one  superiorly,  in  which  the  dorsal  vessels  and  nerves  of 
the  penis  run. — The  erection  of  the  penis  during  life  is 
caused  by  a  greater  quantity  of  blood  than  usually  circu- 
lates through  this  organ  being  propelled  by  an  increased 
action  of  the  arteries  into  the  small  vessels  of  the  corpora 
cavornosa  penis,  this  increased  action  being  induced  by  a 
peculiar  excitement  of  the  nervous  energy  :  anatomists  are 
not  agreed  as  to  the  exact  structure  of  the  corpora  caver- 
nosa,  or  as  to  the  proximate  cause  of  their  erection  during 
life,  or  how  the  blood  is  circumstanced  during  that  condi- 
tion ;  some  consider  that  the  arteries  pour  their  blood  into 
the  cells  of  the  cellular  tissue  which  surrounds  them,  so  as 
to  cause  their  distention,  and  that  from  these  the  blood  is 
slowly  and  gradually  absorbed  by  the  veins ;  others  con- 
ceive that  the  arteries  directly  communicate  with  the  veins, 
and  that  these  latter  vessels  are  tortuous  and  coiled  to  such 
a  degree  as  to  form  plexuses  which  serve  to  retard  the  course 
and  delay  the  return  of  the  blood,  and  so  cause  the  disten- 
tion and  consequent  erection  of  the  whole  organ.* 

The  Urethra  extends  from  the  neck  of  the  bladder  to  the 
extremity  of  the  penis  [and  averages  about  eight  inches  in 
length,  its  diameter  varying  at  different  points ;]  it  is  lined 
by  a  fine  mucous  membrane,  which  is  continuous  posteri- 
orly with  the  mucous  membrane  of  the  bladder,  and  ante- 
riorly with  the  thin  integument,  which  is  reflected  from  the 
inside  of  the  prepuce,  over  the  glans  penis,  as  far  as,  and 
even  within,  the  orifice  of  the  urethra.  Tnis  membrane  is 
covered  at  first  by  the  prostate  gland,  and  this  portion  of 


*  In  a  paper  in  the  Dublin  Hospital  Reports,  vol.  v.,  Dr  Houston  ascribes  the 
erection  of  the  penis,  in  a  great  degree,  to  the  mechanical  obstruction  of  the 
blood  in  the  vena  magna  dorsalis  penis,  caused  by  the  action  of  a  pair  of  muscles, 
named  the  "  compressors  venae  dorsalis  penis ;"  these  muscles  are  very  distinct 
in  the  dog  and  in  other  animals,  and  Dr.  H.  describes  analogous  fibres  in  the  human 
subject;  he  states  that  they  arise  from  the  rami  of  the  pubis,  above  the  origin  of 
the  erectores  penis  and  of  the  crura,  thence  the  fibres  ascend  forwards,  forming 
on  each  side  a  thin,  fleshy,  and  tendinous  stratum,  which  is  inserted  in  common 
in  the  mesial  line  above  the  vena  dorsalis;  these  may,  perhaps,  be  regarded  as 
portions  of  the  erectores  penis  which  instead  of  being  inserted  into  the  crura  mount 
over  them,  in  order  to  compress  the  vena  dorsalis.  The  developenient  of  these 
fibres,  however,  in  man  appears  so  irregular,  weak,  and  imperfect,  that  I  cannot 
concur  in  ascribing  so  much  influence  as  appears  to  be  justly  attributed,  by  com- 
parative anatomists,  to  this  more  perfect  structure  in  some  of  the  lower  animals. 


DUBLIN    DISSECTOR.  227 

tne  canal  is  called  the  prostatic  portion  of  the  urethra ;  the 
next  succeeding  portion  is  covered  by  the  compressores 
urethrse  muscles,  by  the  triangular  ligament,  and  by  a  pe- 
culiar reddish  or  spongy-looking  cellular  tissue,  which  con- 
tains several  small  blood-vessels,  chiefly  veins  ;  this  part  of 
the  urethra  is  called  the  membranous  portion ;  the  remainder 
of  the  canal  is  covered  by  a  cellular  and  vascular  sub- 
stance of  a  dark  red  or  purple  colour,  named  the  corpus 
spongiosum  urethrse,  which  commences  in  the  bulb,  and 
ends  in  the  glans  penis ;  this  portion  of  the  urethra  is 
named  the  spongy  portion.  The  first,  or  the  prostatic  por- 
tion of  the  urethra  is  within  the  pelvis ;  it  is  about  an  inch 
and  a  quarter,  or  an  inch  and  a  half  in  length  ;  in  the  erect 
position  of  the  body  its  direction  is  downwards  and  for- 
wards ;  it  is  nearer  to  the  upper  than  to  the  lower  surface 
of  the  gland. 

[The  membranous  portion  is  from  six  to  ten  lines  long.  Cruveil- 
hier  states  that  it  differs  in  length  at  its  two  edges,  being  superiorly 
an  inch  in  length,  and  inferiorly  but  six  lines,  owing  to  the  projection 
backwards  of  the  bulb.  This  portion  of  the  urethra,  is  the  more 
common  seat  of  stricture,  which  sometimes  leads  to  the  formation  of 
fistula  in  perineo.  There  may  be  a  temporary  obstruction  here  to  the 
passage  of  the  catheter,  from  a  spasmodic  contraction  of  the  com- 
pressor urethrae  muscle,  which  is  to  be  overcome,  by  gentle  but  steady 
pressure.  The  same  thing  may  occur  in  that  part  of  the  urethrse 
covered  by  the  accelerator  urinae  muscle.] 

It  is  described  in  general  as  being  concave  towards  the 
pubes :  it  is,  however,  but  very  slightly  so,  it  runs  nearly 
horizontal,  about  three  quarters  of  an  inch  below  the  sym- 
physis  pubes.  The  spongy  portion  commences  in  the  bulb 
in  front  of  the  triangular  ligament,  extends  to  the  extremity 
of  the  canal,  and  ends  in  the  glans  penis. 

[Its  length  will  depend  upon  that  of  the  penis,  but  allowing  two  to 
two  and  a  quarter  inches  for  the  prostatic  and  membranous  portions, 
this  part  will  average  from  five  and  three  quarters  to  six  inches.] 

This  part  of  the  canal  is  surrounded  by  a  vascular  and 
cellular  texture,  named  the  corpus  spongiosum  urethrse, 
which  has  some  resemblance  to  the  corpora  cavernosa 
penis.  The  corpus  spongiosum  urethrse  consists  of  a  num- 
ber of  fine  cells,  which  communicate  with  each  other ; 
through  these  an  artery  from  each  side  (a  branch  from  the 
internal  pudic)  extends;  these  vessels  send  oif  numerous 
branches,  which  pour  their  blood  into  the  surrounding  cells, 
from  which  the  veins  afterwards  absorb  it ;  the  bulb  and 
the  glans  penis  are  expansions  of  this  cellular  texture,  the 
former  on  the  inferior,  the  latter  on  the  superior  part  and 
sides. 

This  spongy  substance  is  invested  by  a  fine,  but  strong 


228  DUBLIN    DISSECTOR. 

and  semi-transparent  aponeurosis,  very  different  from  that 
which  covers  the  corpora  cavernosa.  The  corpus  spongio- 
sum  surrounds  the  urethra,  but  is  thicker  interiorly  and 
laterally  than  superiorly ;  there  is  no  direct  communica- 
tion between  the  corpus  spongiosum  urethra)  and  the  cor- 
pora cavernosa  penis,  the  one  can,  therefore,  be  distended 
with  air  or  injection  without  the  other,  or  both  may  be  in- 
jected with  different  coloured  fluids.  In  order  to  inject  the 
crura  penis,  make  a  small  opening  in  each  crus  near  its 
attachment  to  the  ischium,  insert  a  pipe  into  one  of  these, 
and  force  warm  water  through  it ;  this  will  soon  escape 
through  the  opening  in  the  opposite  crus,  carrying  along 
with  it  the  blood  which  was  contained  in  the  cells,  then  se- 
cure with  a  ligature  the  opposite  crus,  and  inject  some  co- 
loured fluid.  To  prepare  the  corpus  spongiosum  urethra?, 
make  a  small  opening  in  the  substance  of  the  bulb,  next 
open  the  dorsal  vein  of  the  penis,  in  it  secure  a  small  pipe ; 
water  injected  through  this  will  escape  at  the  opening  in 
the  bulb  :  when  all  the  blood  shall  have  been  thus  washed 
out,  the  latter  opening  may  be  secured,  and  some  coloured 
fluid  injected  along  the  dorsal  vein. 

If,  however,  a  fine  injection  be  forced  from  the  pudic,  or 
from  the  internal  iliac  artery,  it  may  be  made  to  distend 
the  corpora  cavernosa  penis,  and  the  corpus  spongiosum 
urethras  at  one  and  the  same  time.  The  student  may  now 
detach  the  crura  penis  and  the  neck  of  the  bladder  from 
the  pubes,  and  remove  these  organs,  together  with  the  ure- 
thra from  the  subject ;  continue  an  incision  from  the  ante- 
rior  part  of  the  bladder  through  the  upper  part  of  the  pros- 
tate gland,  and  of  the  urethra  to  its  extremity  ;  the  mucous 
lining  of  the  urethra  will  be  thus  exposed,  the  difference 
in  the  diameter  and  other  peculiarities  in  different  parts  of 
it  may  now  also  be  observed.  1st.  The  prostatic  portion  is 
somewhat  contracted  at  either  extremity,  and  dilated  in  the 
centre,  particularly  on  the  lower  surface,  and  at  either  side 
of  the  middle  line  ;  these  enlargements  are  called  the  pros- 
tatic sinuses ;  they  are  separated  from  each  other  by  a  pro- 
minent fold  of  the  lining  membrane,  extending  from  the 
uvula  of  the  bladder  along  the  mesial  line  of  the  urethra, 
as  far  as  the  bulb;  this  fold  is  named  verumontanum,  or 
caput  gallinaginis ;  in  the  centre  of  it  is  a  very  large  la- 
cuna, (sinus  pocularis,}  the  orifice  of  which  is  directed  for- 
wards ;  on  either  side  of  this  pouch,  and  in  general  exter- 
nal to  it,  is  the  opening  of  the  common  ejaculatory  duct, 
external  to  which,  and  in  the  prostatic  sinus  on  each  side, 
are  the  several  small  orifices  of  the  ducts  of  the  prostate 
gland.  3d,  The  membranous  portion  is  shorter,  and  of  a 
smaller  calibre  than  the  prostatic ;  it  is  cylindrical,  its  an- 


DUBLIN    DISSECTOR.  229 

tenor  extremity  is  the  narrowest  portion  of  the  canal.  3d, 
The  spongy  portion  of  the  urethra  is  much  dilated  at  first, 
particularly  inferiorly  (sinus  of  the  bulb ;)  anterior  to  this 
the  small  ducts  of  the  anti-prostatic  glands  open.  The  ca- 
nal of  the  urethra  contracts  a  little  beyond  the  bulb,  and 
continues  of  nearly  the  same  diameter  until  it  arrives  op- 
posite the  scrotum;  it  is  there  slightly  contracted  for  a 
short  distance :  about  an  inch  posterior  to  the  external  ori- 
fice of  the  urethra  the  canal  is  dilated  in  the  transverse  di- 
rection; this  dilatation  is  called  fossa  navicularis ;  lastly,  the 
orifice  of  the  urethra  is  contracted  into  a  narrow  vertical 
slit.  Several  small  lacuna?  open  on  the  surface  of  the  mu- 
cous membrane  of  the  urethra,  between  the  bulb  and  the 
anterior  extremity,  [about  sixty-five  according  to  Loder ;] 
the  orifices  of  these,  in  a  healthy  condition  of  the  mem- 
brane, are  very  small ;  they  are  all  directed  forwards :  if 
bristles  be  introduced  into  some  of  these  ducts  they  will 
be  found  in  many  cases  to  extend  backwards  for  near  an 
inch  in  the  submucous  tissue  ;  these  lacunae  secrete  a  thin 
mucous  fluid,  which  is  expelled  by  the  urine  in  its  passage 
along  the  urethra ;  in  chronic  diseases  of  the  urethra  these 
ducts  not  unfrequently  become  so  much  enlarged  as  to  ad- 
mit the  end  of  a  small  bougie,  and  so  lead  to  the  formation 
of  a  false  passage :  the  largest  lacunae  are  on  the  upper 
surface  of  the  urethra;  one  in  particular,  near  the  fossa 
navicularis,  is  named  the  lacuna  magna.* 

[If  a  section  of  the  pelvis  be  made  by  dividing  it  at  the  symphysis 
pubis,  and  one  of  the  sacro-iliac  symphyses,  leaving  the  rectum, blad- 
der &c.  in  situ,  it  will  be  seen  that  the  urethra  in  its  natural  position 
presents  two  curves,  one  behind  the  triangular  ligament,  which  is 
somewhat  concave  above,  and  the  other,  before  the  triangular  ligament, 
which  presents  its  convex  aspect  upwards  and  forwards  ;  if  then  the 
penis  be  carried  up  towards  the  abdomen,  the  second  curve  will  be 
entirely  obliterated,  and  the  whole  urethra  will  present  a  single  sweep, 
the  concavity  of  which  looks  upwards,  hence  the  curved  catheter  is 
more  commonly  used  ;  but  the  straight  instrument  may  be  readily 


+  During  the  dissection  of  the  pelvic  viscera,  perinoeum,  &c.  the  student  should 
frequently  practise  the  introduction  of  a  catheter  into  the  bladder,  which  is  to  be 
done  in  the  following;  manner:  the  subject  lying  on  iis  back  with  the  legs  drawn 
up,  the  penis  should  be  held,  by  placing  the  thumb  and  index-finger  on  each  side 
of  the  corona  glandis,  by  which  means  the  orifice  of  the  urethra  will  not  be  com- 
pressed ;  the  penis  is  then  to  be  drawn  upwards,  and  the  catheter,  being  previously 
oiled,  is  next  to  be  introduced  in  a  line  with  the  linea  alba  into  the  urethra,  di- 
rectly downwards  as  far  as  the  bulb  ;  the  concavity  of  the  instrument  being  to- 
wards the  abdomen.  The  catheter  having  reached  the  bulb,  its  handle  is  to  be 
depressed  by  bringing  it  forwards  between  the  thighs,  and  in  proportion  as  this  is 
done,  the  point  is  elevated,  and  the  catheter  glides  into  the  bladder ;  in  this 
latter  part  of  the  operation,  the  penis  must  be  allowed  to  sink  down,  for  if  it  be 
kept  extended  on  the  instrument,  the  membranous  part  of  the  urethra  would  be 
drawn  towards  the  pubes,  by  which  means  the  introduction  of  the  instrument 
would  be  rendered  difficult. 

20 


230  DUBLIN     DISSECTOR. 

introduced  by  drawing  firmly  upon  the  penis,  at  an  angle  of  forty-five 
degrees.] 

The  testicle  is  the  seat  of  many  morbid  appearances, 
both  in  its  tunics  and  in  its  substance ;  hydrocele  is  very 
common,  this  is  a  dropsy  in  the  serous  cavity  of  the  tunica 
vaginalis ;  this  latter  membrane  may  be  inflamed,  and  the 
adhesive  process  may  obliterate  its  cavity.  The  tunica 
albuginea  is  sometimes  the  seat  of  a  firm  fungus  which 
protrudes  through  the  other  coverings  to  the  surface.  The 
testicle  and  epididymis  may  be  the  seat  of  acute  inflamma- 
tion, as  in  hernia  humoralis  the  effect  of  gonorrhoea,  also 
of  chronic  inflammation  with  indolent  enlargement,  or 
sarcocele.  The  testis  is  also  the  frequent  seat  of  strumous 
inflammation  and  suppuration,  of  fungoid  disease  in  which 
there  is  great  enlargement,  total  change  of  structure  and 
conversion  into  cerebriform  matter ;  of  true  scirrhus  and 
cancer,  of  hydatid  tumours,  &c. :  these  glands  are  also 
sometimes  atrophied.  The  spermatic  cord  is  sometimes 
the  seat  of  encysted  hydrocele,  of  varicocele,  particularly 
on  the  left  side,  as  also  of  different  tumours. 

[Another  disease  in  the  vaginal  cavity  is  hematocle,  or  an  ac- 
cumulation of  blood,  or  of  blood  and  serum.  Sometimes  the  inner 
surface  of  the  tunic  is  much  roughened  by  the  deposition  of  fibrine. 
In  recent  hydroceles,  the  tunica  vaginalis  is  transparent,  but  in  old 
cases  it  is  thick  and  opaque,  and  sometimes  is  partially  converted 
into  cartilage  or  even  bone.  In  the  radical  treatment  of  hydrocele  the 
great  object  is  to  bring  about  adhesive  inflammation,  and  obliteration 
of  the  sac.  We  sometimes  find  tubercles  in  the  testicle,  either  in  its 
substance,  or  on  its  surface  or  in  the  epididymis,  they  rarely  occur  in 
both  testicles  at  the  same  time.  Hydrocele  of  the  cord  sometimes  oc- 
curs from  the  passage  between  the  abdomen  and  scrotum,  not  being 
completely  obliterated  at  all  points.] 

The  prostate  gland  is  seldom  found  diseased,  except  in 
old  men;  it  is  rarely  inflamed,  an  abscess  however  has 
been  met  with  (unaccompanied  by  any  thickening)  in  its 
substance,  arising  from  common  inflammation.  Scirrhus. 
The  most  common  disease  of  the  prostate  gland  is  scirrhus ; 
the  gland  in  its  natural  state  is  known  to  be  about  the  size 
of  a  chestnut,  but  when  it  is  affected  with  scirrhus,  it  is 
often  enlarged  to  the  size  of  the  fist.  The  common  ap- 
pearances observed  in  scirrhus  in  other  parts  of  the  body, 
can  be  plainly  seen  in  this  gland;  when  cut  into,  it  ap- 
pears to  consist  of  a  very  solid,  whitish,  or  brown  substance, 
with  membranous  septa,  running  through  it  in  various  di- 
rections. According  to  the  degree  of  enlargement  that 
takes  place,  the  urine  is  passed  through  the  bladder  with 
greater  or  less  difficulty,  as  well  as  an  instrument  for  draw- 
ing it  off.  Calculi  have  been  found  lodged  in  the  ducts  of 


DUBLIN    DISSECTOR.  231 

the  prostate  gland ;  they  are  usually  small  granules  of  a 
dark  colour,  and  give  it  a  mottled  appearance  when  cut  into. 
[Tubercles  are  occasionally  found  in  the  prostate.  When  this  or- 
gan is  enlarged  it  presents  an  obstacle  to  the  discharge  of  urine  and 
even  to  the  passage  of  the  catheter;  it  sometimes  is  necessary  to  in- 
troduce  the  finger  two  inches  and  a  half  into  the  rectum  under  the 
prostate,  so  as  to  lift  up  the  point  of  the  instrument  over  the  obstruc- 
tion, which  is  more  commonly  on  the  und>er  side  of  the  urethra.  In 
these  cases  of  enlarged  prostate  the  bladder  becomes  very  much  con- 
tracted, and  the  muscular  coat  very  thick  and  distinct.  This  en- 
largement sometimes  occurs  in  young  men  from  acute  inflammation 
of  a  gonorrheal  character.] 

The  vesiculoe  seminales  are  seldom  found  diseased;  in 
cases  of  scrofulous  testicle  they  have  been  found  similarly 
affected  and  filled  with  cheesy  fluid.  The  urethra  is  the 
frequent  seat  of  inflammation,  which  when  recent  produces 
suppuration  without  ulceration,  and  if  long  continued, 
causes  a  thickening  of  the  submucous  tissue,  and  thus  ren- 
ders the  canal  narrow  and  irregular,  and  so  commences 
the  foundation  of  stricture. 

[The  most  common  seat  of  this  affection  is  the  membranous  part 
of  the  urethra,  the  next  most  common  seat,  is  about  four,  or  four  and 
a  half  inches  from  its  orifice,  and  next  just  behind  the  glans  penis. 
The  urethra  is  sometimes  malformed  ;  it  may  open  upon  the  upper  or 
under  surface  of  the  penis, epispadias  and  hypospadias  ;  it  may  termi- 
nate in  the  perineum,  or  above  the  pubes.  All  of  these  malforma- 
tions do  not  necessarily  imply  impotence,  sometimes  the  rectum  ter- 
minates in  the  urethra  of  the  male,  and  I  have  known  a  case  of  this 
kind  in  which  the  child  lived  a  year  and  then  died  of  inflammation, 
caused  by  the  arrest  of  an  apple  seed  near  the  orifice  of  the  urethra.] 

The  coverings  of  the  penis  are  the  frequent  seat  of  ulce- 
ration, also  those  of  the  glans  penis ;  the  latter  in  old  per- 
sons is  very  often  attacked  with  warty  cancerous  ulcera- 
tion. 


CHAPTER  VII. 
SECTION  L 

DISSECTION    OF    THE    FEMALE    ORGANS    OF   GENERATION. 

THE  generative  organs  in  the  female  are  more  distinct 
from  the  urinary  than  in  the  male  subject ;  they  may  be 
.divided  into  the  external  and  internal ;  the  external  parts 


232  DUBLIN    DISSECTOR. 

are  the  mons  veneris,  vulva,  labia,  clitoris,  nymphse,  vagi- 
na, and  perinseum. 

The  mons  veneris  is  an  eminence  placed  on  the  upper  and 
anterior  part  of  the  pubes  ;  it  consists  of  a  quantity  of  adi- 
pose substance  beneath  the  integuments,  which  in  the  adult 
are  covered  with  hair.  The  vulva  is  the  fissure  which  ex- 
tends from  the  mons  veneris  to  within  an  inch  of  the  anus. 
The  anterior  perin&um  is  the  small  space  in  front  of  the 
anus,  the  posterior  perinaum  is  between  the  anus  and  the 
os  coccygis.  The  labia  externa  or  majora,  are  the  thick 
folds  of  integument  which  extend  one  on  each  side  of  the 
vulva,  and  are  united  inferiorly  in  a  crescentic  edge,  call- 
ed the  commissure  or  fourchette.  The  clitoris  is  below  the 
superior  angle  or  commissure  of  the  labia :  it  is  a  small 
red  projection  immediately  beneath  the  symphysis  pubis 
and  above  the  vagina ;  it  is  attached  by  two  crura  to  the 
rami  of  the  pubes ;  these  unite  and  form  the  body  of  the 
clitoris,  on  the  anterior  extremity  of  which  is  a  round  red 
swelling  called  the  glans  clitoridis  ;  this  is  covered  by  a 
thin  loose  fold  of  integument  or  mucous  membrane  called 
the  prepuce.  The  clitoris  is  composed  internally  of  a 
spongy  cellular  texture,  not  very  unlike  the  corpus  spon- 
giosum  urethra?  in  the  male  subject.  The  nymphcc,  or  labia 
minora,  descend  one  on  each  side  of  the  vagina,  from  the 
prepuce  of  the  clitoris,  and  are  gradually  lost  about  the 
centre  of  the  vulva. 

About  half  an  inch  below  and  a  little  behind  the  clitoris 
and  between  the  nymphse,  is  the  round  orifice  of  the  mea- 
tus  urinarius ;  this  opening  is  surrounded  by  a  projecting 
fold  of  mucous  membrane,  on  the  sides  of  which  are  the 
orifices  of  small  mucous  glands  analogous  to  Cowper's 
glands  in  the  male.  The  meatws  is  from  an  inch  and  a 
half  to  two  inches  in  length ;  it  leads  backwards  and  up- 
wards along  the  upper  surface  of  the  vagina,  and  is  slight- 
ly curved  beneath  the  symphysis  pubis,  to  which,  as  also 
to  the  crura  of  the  clitoris,  it  is  attached  by  the  triangular 
ligament. 

[There  are  two  rules  given  for  the  introduction  of  the  catheter  in 
the  female  ;  one  is  to  feel  for  the  clitoris  and  then  to  carry  the  finger 
down  about  three  quarters  of  an  inch  until  it  rests  upon  a  tubercular 
elevation,  on  which  the  orifice  of  the  urethra  will  be  found  :  the 
other  rule  is  to  carry  the  finger  directly  to  the  lower  edge  of  the 
symphysis  pubis ;  just  below  which  is  the  tubercle  above  referred  to : 
this  last  is  the  better  rule,  as  by  it  we  avoid  as  far  as  possible  the 
handling  of  the  parts  ;  if  the  uterus  be  very  much  enlarged  from 
disease,  or  pregnancy,  the  situation  of  the  bladder  and  urethra  will 
be  changed,  so  that  the  latter  will  lie  behind  the  symphysis  and  nearly 
parallel  to  it,  in  which  case  after  the  point  of  the  catheter  is  intro- 


DUBLIN    DISSECTOR.  233 

duced  into  the  orifice  of  the  urethra,  the  handle  must  be  depressed 
far  back  between  the  thighs  of  the  patient.] 

The  vagina  is  directly  below  the  urethra  :  in  the  child  it 
is  partially  closed  in  front  by  a  crescentic  fold  of  mem- 
brane, termed  the  hymen  :  in  the  adult  several  reddish  emi- 
nences [the  carunculse  myrtiformes]  surround  this  open- 
ing ;  the  course  and  connexions  of  this  canal  will  be  better 
seen  when  the  pelvis  shall  have  been  divided  for  the  pur- 
pose of  examining  the  internal  organs  of  generation.  Dis- 
sect off  the  integuments  and  fascia  from  the  perineum  and 
labia,  and  the  following  muscles  may  be  seen  :  the  sphinc- 
ter ani,  levatores  ani,  and  coccygai ;  these  are  similar  to  the 
muscles  of  the  same  name  in  the  male  perinseum,  also  the 
transfer  sales  perin&i :  the  erectores  cliloridis  are  analogous  to 
the  compressores  penis ;  and  the  sphincter  vagina  corres- 
ponds to  the  accelatores  urinse  ;  it  extends  from  the  clitoris 
superiorly  around  each  side  of  the  vagina  to  the  central 
point  of  the  perinseum  in  front  of  the  anus. 

To  examine  the  internal  organs  of  generation  make  a 
lateral  section  of  the  pelvis  in  the  same  manner  as  was  di- 
rected in  the  dissection  of  the  male  pelvis.  The  perito- 
naeum may  be  first  examined  ;  this  will  be  seen  to  descend 
along  the  fore  part  of  the  rectum,  to  within  three  or  four 
inches  of  the  anus ;  it  is  thence  reflected  forwards  on  the 
posterior  part  of  the  vagina,  the  superior  third  of  which  it 
covers  ;  from  the  vagina  it  ascends  on  the  posterior  surface 
and  sides  of  the  uterus ;  continues  round  the  superior  fun- 
dus  of  this  organ  to  its  anterior  part,  on  which  it  descends 
as  low  as  the  commencement  of  the  vagina,  it  is  thence  re- 
flected to  the  bladder,  and  is  continued  over  this  organ,  as 
in  the  male  subject,  to  the  abdominal  muscles ;  thus,  in  the 
female  pelvis,  the  peritonaeum  forms  one  cul  de  sac  between 
the  rectum  and  vagina,  and  another  between  the  uterus  and 
bladder.  From  each  side  of  the  uterus  a  broad  fold  of  pe- 
ritonseum  is  extended  transversely  towards  each  iliac  fos- 
sa ;  these  folds  are  the  broad  ligaments  of  the  uterus ;  en- 
closed between  the  lamin®  of  each  of  these  are  the  Fallo- 
pian tube,  the  round  ligament  of  the  uterus,  and  the  ovarium 
with  its  ligament  and  vessels,  Dissect  off  the  peritonaeum 
from  one  side  of  the  rectum  and  vagina,  and  the  pelvic  vis- 
cera will  be  more  distinctly  seen. 

The  rectum  takes  the  same  course  as  in  the  male  only 
somewhat  more  curved,  it  lies  behind  the  uterus  and  vagi- 
na, to  the  latter  it  is  united  by  a  close  vascular  plexus. 
The  vagina  is  seen  to  surround  the  neck  of  the  uterus,  and 
thence  to  descend  obliquely  downwards  and  forwards  for 
about  six  or  seven  inches  between  the  rectum,  the  bladder, 
20* 


234  DUBLIN    DISSECTOR. 

and  urethra  ;  closely  connected  to  the  latter,  and  but  loose- 
ly to  the  rectum. 

[The  length  of  the  vagina  in  a  healthy  state,  varies  very  much  in 
different  individuals  ;  it  has  been  seen  but  one  inch  and  a  half  long  ; 
it  varies  also  in  the  same  individual  under  different  circumstances, 
being  about  six  inches  long  in  the  virgin,  and  about  four  in  the  woman 
who  has  borne  children  ;  its  apparent  length  also  varies  at  different 
periods  of  utero- gestation,  owing  to  the  different  positions  of  the 
uterus ;  its  capacity  also  varies  very  much,  being  much  greater  in 
those  who  have  borne  children  than  in  those  who  have  not ;  its  capa- 
city however  is  always  greatest  at  its  upper  pa.t,  where  it  receives 
the  mouth  of  the  uterus.  Its  great  extensibility  is  proved  during  par- 
turition.] 

The  vagina  is  lined  by  a  vascular  mucous  membrane, 
which  is  transversely  rugose,  and  is  covered  externally  by 
a  dense  fibrous  tissue  and  by  numerous  vessels,  particular- 
ly veins,  which  form  a  plexus  (retiform)  or  spongy  body, 
which  is  situated  beneath  the  sphincter  vaginae  muscle ; 
the  vagina  is  also  partially  covered  by  peritoneum  on  its 
posterior  surface.  Between  the  bladder  and  vagina  the 
ureter  may  be  observed  ;  its  course  is  longer  and  more  curv- 
ed in  the  female  pelvis  than  in  the  male. 

The  Uterus  is  situated  between  the  bladder  and  rectum, 
and  connected  to  both  by  peritonaeum ;  the  broad  ligament 
which  is  a  fold  of  peritonaeum,  and  the  round  ligament 
which  is  a  fasciculus  of  blood-vessels  and  nerves  bound 
together  by  dense  cellular  tissue,  connect  each  side  of  this 
organ  to  the  pelvis,  and  to  the  inguinal  regions.  The  ute- 
rus is  somewhat  pyriform  or  triangular,  the  larger  end  or 
fundus  being  superiorly  and  posteriorly,  the  smaller  end  or 
cervix  inferiorly  and  anteriorly  ;  the  intermediate  portion 
is  named  the  body ;  the  vagina  surrounds  the  cervix  uteri, 
and  ascends  higher  posteriorly  than  anteriorly  ;  at  the 
lower  extremity  of  the  cervix  is  a  small  transverse  slit, 
termed  the  os  uteri  or  os  tinea* 

[It  is  -bounded  by  the  lips  of  the  uterus  of  which  ths  anterior  is  the 
thickest,  and  is  continuous  with  the  anterior  wall  of  the  vagina,  while 
the  posterior  is  thinner  and  longer,  and  is  attached  by  its  base  to  the 
posterior  wall  of  the  vagii-a,  hence  it  projec's  into  the  latter  organ, 
which  forms  behind  it  a  large  cul  de  sac.  The  uterus  varies  much 
in  size  in  chr.ldhood,  youth,  and  adult  life  ;  it  is  larger  and  firmer  in 
those  who  have  borne  children  than  in  those  who  have  not.  It  is  from 
twelve  to  fourteen  lines  long  at  birth,  and  but  an  inch  and  a  half 
long,  at  ten  years  of  age,  so  that  it  is  aimost  stationary,  until  the  age 
of  puberty  at  which  period  it  is  suddenly  and  rapidly  developed,  and 
filled  for  its  future  functions.  In  the  adult  female  the  average  size 
of  the  organ  is  as  follows;  length  two  and  a  half  to  three  inches; 
breadth  at  the  fallopian  tubes  an  inch  and  a  half,  at  the  neck  six  to 
twelve  lines  ;  thickness  ten  to  twelve  lines ;  medium  thickness  of  the 


DUBLIN    DISSECTOR.  235 

parietics  of  the  body  five  lines,  of  the  neck  four,  thickness  of  the  lips 
three  to  four  lines ;  heighth  of  fundus  above  the  fallopian  tubes  a  quarter 
of  an  inch.  The  weight  of  the  organ  averages  at  puberty  from  six  to 
ten  drachms  ;  in  the  adult  from  one  and  a  half  to  two  ounces,  and  at 
the  full  term  of  utero-gestation  from  one  and  a  half  to  three  pounds. 
The  cavity  of  the  body  of  the  uterus  is  an  equilateral  triangle  flat, 
tened  antero-posteriorly,  with  its  sides  convex  internally,  its  diameter 
is  about  ten  lines  at  its  greatest,  and  much  less  at  the  angles ;  the 
cavity  of  the  neck  is  about  an  inch  long  with  a  diameter  of  three  or 
four  lines,  it  is  somewhat  cylindrical  in  form,  but  wider  at  its  centre 
than  its  extremities  ;  the  sides  being  concave  towards  each  other. 
The  situation  of  the  uterus  varies  very  much  with  the  period  of  life 
and  of  utero-gestation,  in  the  fetus  and  infant  it  is  in  the  cavity  of 
the  abdomen.] 

The  uterus  consists  of  a  dense  fibrous  substance,  perfo- 
rated by  a  great  many  vessels,  covered  externally  by  peri- 
tonaeum, and  lined  throughout  by  mucous  membrane,  which 
is  continued  from  the  vagina  throughout  the  entire  organ, 
and  thence  into  the  Fallopian  tubes,  along  which  it  ex- 
tends to  their  fimbriated  extremity,  where  it  becomes  con- 
tinuous with  the  peritonaeum  on  each  side,  thus  presenting 
a  singular  example  of  the  continuity  of  a  mucous  and  se- 
rous "membrane  with  each  other:  the  mucous  membrane 
of  the  uterus  is  often  of  a  very  dark  colour,  and  is  marked 
by  several  lines.  The  cavity  of  the  uterus  is  very  small, 
and  somewhat  triangular,  being  larger  in  the  superior  fun- 
dus  than  elsewhere. 

The  Fallopian  tubes  are  from  four  to  five  inches  in  length  ; 
they  extend  from  the  fundus  uteri  upwards  and  outwards  at 
lirst,  and  then  a  little  downwards  and  backwards  ;  each  ter- 
minates in  a  soft  fringed  extremity,  called  Corpus  fimbria- 
tum,  which  communicates  with  the  cavity  of  the  peritoneum 
and  which  overhangs  the  ovary ;  these  canals  are  narrow 
where  they  join  the  uterus,  but  each  increases  in  size  near 
the  corpus  fimbriatum. — The  ovaria  are  two  small,  white, 
flattened,  oval  bodies,  one  at  each  side,  enclosed  in  the  pos- 
terior fold  of  the  broad  ligament,  and  behind  the  Fallopian 
tube  ;  their  surface  is  often  irregular  and  as  it  were  cica- 
trized.— Each  ovary  is  connected  to  the  side  of  the  uterus 
by  the  broad  ligament  of  the  latter,  also  by  a  round  fibrous 
cord,  the  proper  ligament  of  the  ovary  ;  this  is  about  two 
inches  long,  and  is  enclosed  between  the  laminae  of  the 
broad  ligament  of  the  uterus.  Each  ovary  is  covered  by 
the  peritonaeum,  which  adheres  very  closely  to  it ;  beneath 
this  is  a  strong  white  fibrous  capsule,  within  which  a  num- 
ber of  small  vesicles  will  be  found  connected  together  by 
cellular  membrane  and  vessels. 

[The  ovaries  vary  in  size  with  age,  and  they  are  proportionably 


236  DUBLIN    DISSECTOR. 

large  in  the  foetus  and  child  ;  their  average  size  in  eight  females,  be- 
tween  the  ages  of  seventeen  and  twenty-three  was  found  to  be,  length 
seventeen  lines,  breadth  nine  lines,  thickness  four  lines  and  a  half, 
and  weight  one  drachm  and  a  quarter  :  they  are  heavier  in  those  who 
have  borne  children  than  in  others.  The  ovaries  of  women  who 
have  had  children  present  upon  their  surfaces,  cicatrices  which  cor- 
respond to  certain  bodies  internally,  which  are  called  the  corpora 
lutea  and  which  are  supposed  to  be  the  debris  of  impregnated  ova. 
The  female  organs  of  generation  present  many  anomalies  of  confor- 
mation. The  uterus  and  vagina  are  sometimes  a  solid  mass  having 
no  cavity,  the  uterus  is  sometimes  entirely  wanting  either  with  or 
without  a  corresponding  deficiency  of  the  tubes  and  ovaries,  gene- 
rally however  the  latter  is  the  case  :  the  uterus  is  sometimes  divided 
by  a  longitudinal  septum  into  two  cavities,  which  open  separately 
into  the  same  vagina  or  each  has  its  own  vagina  :  the  uterus  may 
present  two  horns  or  cornua  as  in  many  of  the  inferior  animals  :  it 
may  also  be  absolutely  double,  the  two  organs  opening  into  a  common 
vagina,  each  into  its  own  vagina,  or  one  into  the  vagina  and  the  other 
into  the  rectum  :  the  mouth  of  the  uterus  is  sometimes  completely 
obliterated,  of  this  I  have  a  specimen  from  a  female  between  fifty 
and  sixty  years  of  age  ;  perhaps  the  cases  of  superfoetation,  may  be 
explained  by  referring  to  some  of  the  anomalies  above  mentioned. 
One  ovary  is  sometimes  wanting,  the  other  being  larger  than  usual ; 
the  fallopian  tubes  may  be  imperforate.  The  vagina  is  sometimes 
solid,  sometimes  imperforate,  from  the  presence  of  the  hymen  or  an 
anomalous  septum,  it  is  sometimes  double,  sometimes  it  communi- 
cates with  the  bladder,  and  at  other  times  with  the  rectum  ] 

The  female  organs  of  generation  are  the  seat  of  many 
morbid  changes.  Not  to  notice  the  various  ulcerations  to 
which  the  external  parts  are  liable,  we  occasionally  find 
here  also  polypi,  adipose  and  sarcomatous  tumours  in  the 
labia,  enlargement  of  the  clitoris,  &c. 

The  uterus  may  be  found  inflamed,  (matritis),  this  oc- 
curs soon  after  parturition,  the  adjacent  peritonaeum  is  also 
generally  affected ;  the  uterus  itself  exhibits  the  same  ap- 
pearances as  the  inflammation  of  the  substance  of  other 
parts ;  the  inflammation  is  found  to  creep  along  the  Fallo- 
pian tubes  and  ovaries.  It  often  advances  to  suppuration, 
and  pus  is  generally  found  in  the  large  veins  of  the  womb. 
When  the  peritonaeum  is  inflamed,  it  has  been  remarked, 
that  the  extravasated  fluid  and  coagulabie  lymph  are  found 
in  a  greater  proportion  to  the  degree  of  inflammation,  than 
in  common  peritonitis.  Polypus.  Polypi  are  very  fre- 
quently found  in  the  uterus ;  they  may  grow  at  any  period 
of  life,  but  they  are  rarely  met  with  in  the  young.  By  a 
polypus  is  meant  a  diseased  mass,  which  adheres  to  the 
cavity  of  the  uterus,  by  a  sort  of  a  neck  or  narrower  por- 
tion. Polypus  is  of  two  different  kinds  ;  the  most  common 
kind  is  hard,  and  consists  of  a  substance  divided  by  thick 
membranous  septa ;  this  sort  of  polypus  varies  very  much 


DUBLIN    DISSECTOR.  237 

in  its  size,  some  not  being  larger  than  a  walnut,  and  others 
being  larger  than  a  child's  head.  Another  sort  of  polypus 
forms  in  the  uterus,  which  consists  of  an  irregular  bloody 
substance,  with  tattered  processes  hanging  from  it ;  when 
cut  into  it  appears  to  be  a  spongy  mass,  holding  large  cells. 
The  most  common  part  to  which  polypi  adhere,  is  the  fun- 
dus  uteri,  and  sometimes  they  are  found  attached  to  the  os 
tineas.  Hard  fibrous  tumours  also  not  unfrequently  exist 
in  the  parietes  of  the  uterus. — The  uterus  is  also  frequently 
the  seat  of  cancer,  which  usually  commences  near  the  os 
tincse.  The  uterus  also  is  subject  to  partial  displacement, 
viz.  prolapsus,  inversio,  and  retroversio. 

The  membrane  covering,  or  the  substance  of  the  ovary, 
are  very  rarely  found  inflamed,  except  when  they  are  in- 
cluded in  general  peritonitis ;  when  the  inflammation  pro- 
ceeds from  the  uterus,  it  sometimes  goes  on  to  the  forma- 
tion of  pus  in  the  ovary.  Dropsy.  The  most  common  dis- 
ease in  the  ovary  is  dropsy,  the  whole  snbstance  of  the 
ovarium  is  sometimes  converted  into  a  capsule  containing 
fluid.  When  the  ovaria  have  become  dropsical,  their  nat- 
ural structure  has  disappeared,  and  they  are  found  convert- 
ed into  cells,  communicating  with  one  another  by  consider- 
able openings,  and  very  much  enlarged :  the  ovaria  are 
sometimes  converted  into  a  series  of  cysts,  which  have  no 
communication  with  each  other ;  these  cysts  have  been 
confounded  with  hydatids,  to  which  they  bear  some  resem- 
blance ;  they  are  however  very  different ;  they  have  much 
firmer  and  less  pulpy  coats  than  hydatids,  they  contain  a 
different  kind  of  fluid,  and  they  are  differently  connected 
among  themselves.  Hydatids  either  lie  unconnected,  or 
one  large  one  encloses  a  number  of  small  ones ;  while 
ovarian  cysts  adhere  to  each  other  by  broad  surfaces,  and 
do  not  enclose  each  other.  The  ovaria  are  sometimes 
found  converted  into  cysts,  holding  large  masses  of  fat, 
hair,  and  some  teeth  ;  these  substances  appear  to  be  gene- 
rated by  the  internal  membrane  of  the  cyst ;  the  hairs  are 
most  of  them  loose  in  the  fatty  substance,  but  many  of  them 
adhere  to  the  inside  of  the  capsule ;  the  teeth,  which  are 
not  always  perfect,  are  sometimes  attached  to  the  cyst,  and 
at  others,  to  an  irregular  mass  of  bone. 


238  DUBLIN    DISSECTOR. 


CHAPTER    VIII. 


DISSECTION  OF  THE  INFERIOR  EXTREMITIES. 

EACH  inferior  extremity  is  connected  to  the  trunk  by  the 
strong  ligaments  of  the  hip  joint,  and  by  several  muscles 
which  pass  from  the  pelvis  to  the  thigh  and  leg.  This  dis- 
section may  be  performed  while  the  pelvis  remains  attach- 
ed to  the  spine,  or  the  former  may  be  separated  from  the 
lumbar  vertebrae,  and  divided  into  two. 

[The  muscles  of  the  inferior  extremity  are  very  differently  arranged 
from  those  of  the  superior.  The  great  locomotive  functions  of  the 
inferior  extremities  are  progression,  and  retrogression,  accordingly  we 
find  that  the  flexor  and  extensor  muscles,  are  on  opposite  sides  of  the 
limb,  and  that  they  change  their  relative  position  in  each  subregion 
of  the  extremity;  while  in  the  superior  extremity  the  flexor  muscles 
are  all  on  the  same  aspect  of  the  limb,  and  so  too  with  the  extensors. 
Besides  flexion  and  extension,  the  motions  of  these  extremities,  in- 
elude  rotation  inwards  and  outwards,  adduction  and  abduction,  which 
movements  are  effected  either  by  special  and  appropriate  muscles,  or 
by  certain  of  the  flexors  and  extensors  :  of  the  former  fact,  we  have 
an  illustration,  in  the  rotator  muscles  of  the  thigh  ;  of  the  latter  in 
the  tibiales  anticus  and  posticus  ;  the  former  flexes  the  foot  upon  the 
leg,  the  latter  extends  it,  yet  both  together,  turn  the  foot  inwards  and 
upwards.  As  in  the  case  of  the  upper,  so  in  the  lower  extremities, 
the  muscles  should  be  classed  as  nearly  as  possible  according  to  their 
functions,  and  we  find  that  they  may  be  examined  in  the  four  regions 
of  the  hip,  the  thigh,  the  leg,  and  the  foot ;  this  arrangement  has 
reference  to  the  part  of  the  extremity,  upon  which  the  muscle  chiefly 
lies;  again  in  the  several  regions  the  muscles  are  arranged  in  classes 
having  reference  to  the  particular  part  of  the  limb  on  which  they  act, 
and  lastly  the  classes  are  divided  into  groups,  according  to  the  par- 
ticular and  principal  motion  effected  by  their  contraction  as  flexion 
extension,  &/c.  In  proceeding  with  the  muscles  which  act  upon  the 
inferior  extremity,  we  examine  first  the  region  of  the  hip,  in  which 
we  find  but  one  class  of  muscles,  all  acting  upon  the  thigh,  these  are 
twelve  in  number,  on  each  side,  arranged  in  three  groups,  the  flexors 
three,  the  extensors  three,  and  the  rotators  six,  as  follows. 

First  Group,  Flexors. 

The  psoas  parvus  is  inserted  here  rather  as  a  matter  of  expediency, 
than  propriety,  not  because  it  is  a  flexor  of  the  thigh  but  from  its 
position,  and  because  it  is  in  some  respects  a  congener  of  the  psoas 
magnus. 

1.  Psoas  Parvus,    )    T7-.,        in_ 

2.  Psoas  Magnus,  (    Vlde  P'  195' 

3.  Iliacus  Inlernus,    Vide  p.  196. 


DUBLIN    DISSECTOR.  239 

Second  Group,  Extensors. 

1.  Gluteus  Maxim  us,  Vide  p.  254. 

2.  Gluteus  Medius,  ««     "  255. 

3.  Gluteus  Minimus,  ««     "  256. 

Third  Group,  Rotators. 

1.  Pyriformis,  Vide  p.  256. 

2.  Obturator  Interims,  ««     "  257. 

3.  Obturator  Externus,  } 

4.  Gemellus  Superior,     >  Vide  p.  259. 

5.  Gemellus  Inferior,      S 

6.  Quadratus  Femoris,  Vide  p.  258. 

Of  these  groups  the  first  is  situated  anteriorly,  for  the  most  part  in 
the  abdomen ;  the  second  and  third  are  posteriorly,  on  and  about  the 
dorsum  of  the  ilium,  and  are  found  in  three  layers,  in  the  first  the 
gluteus  maximus,  in  the  second  the  gluteus  medius,  and  in  the  third 
the  gluteus  minimus,  anteriorly  and  superiorly,  and  the  six  rotators 
posteriorly  and  inferiorly.  The  muscles  on  the  region  of  the  thigh 
are  fifteen  in  number,  on  each  side,  and  are  arranged  in  two  classes, 
one  acting  upon  the  leg,  the  other  upon  the  thigh ;  in  the  first  class 
there  are  three  groups,  the  superficial  group  of  three  muscles,  the 
flexors  four,  and  the  extensors  also  four ;  in  the  second  class  there  is 
but  one  group,  of  four  muscles,  the  adductors. 

FIRST    CLASS. 

First  Group. 

Three  superficial  muscles  at  the  outer,  fore,  and  inner  part  of  the 
thigh. 

1.  Tensor  vaginae  femoris,  an  abductor  and  rotator  } 

of  the  thigh,  and  which  acts  upon  the  outside  of  the  >  Vide  p.  245. 
leg,  through  the  fascia  lata.  i 

2.  Sartorius,  a  flexor  of  the  leg,  and  adductor  of  the 
whole  limb. 

3.  Gracilis,  a  flexor  of  the  leg  and  adductor.  Vide  p.  249. 

Second  Group. 
Four  extensors  of  the  leg,  situated  on  the  anterior  aspect  of  the  thigh. 

1.  Rectus  Femoris,  which  also  flexes  the  thigh  upon 
the  pel  vis. 

2.  Vastus  Externus,  Vide  p.  247. 

3.  Vastus  Internus,  ««     "  248. 

4.  Crureus  or  Cruralis,  beneath  which  at  the  lower  ) 
part  of  the  thigh,  is  sometimes  found  the  Subcrureus.   \ 

Third  Group. 

Four  flexor  muscles  of  the  leg,  situated  on  the  posterior  aspect  of 
the  thigh. 

1.  Biceps  Flexor  Cruris,  Vide  p.  261. 

2.  Semi-Membranosus,  "    "  262. 

3.  Semi-Tendinosus,  "     "  261. 

4.  Popliteeus,  "     •«  273. 


240  DUBLIN    DISSECTOR. 

SECOND  CLASS,  ONE  GROUP. 

Four  adductor  muscles  situated  at  the  inner,  back,  and  fore  part  of 
the  thigh,  and  most  of  which  also  assist  in  flexion  of  the  thigh  upon 
the  pelvis. 

1.  Pectineus,  Vide  p.  249. 

2.  Adductor  Longus,  "     "  250. 

3.  Adductor  Brevis,  "     "  250. 

4.  Adductor  Magnus,  "     "  251. 

The  muscles  on  the  region  of  the  leg  are  twelve  in  number  on  each 
side,  and  are  arranged  in  two  classes  :  the  first  class  acts  upon  the 
foot  as  a  whole,  and  consists  of  three  groups,  one  group  posteriorly 
which  extends  the  foot  upon  the  leg,  a  second  group  along  the  fibula, 
and  a  third  group  along  the  tibia,  in  which  two  groups  some  of  the 
muscles  are  flexors,  and  some  extensors  of  the  foot  upon  the  leg. 
The  second  class  consists  of  two  groups  which  act  primarily  upon  the 
toes,  and  if  their  action  be  continued,  secondarily  upon  the  foot. 

FIRST    CLASS. 

First  Group. 

Three  extensor  muscles  of  the  foot,  situated  on  the  posterior  aspect 
of  the  leg.  The  two  first  by  their  fleshy  bellies  forming  the  calf  of 
the  leg,  and  lower  down  joining  to  form  the  tendo  achillis. 

1.  Gastrocnemius,  Vide  p.  271 


Second  Group. 

Three  muscles  situated  along  the  fore,  back,  and  outer  part  of  the 
fibula,  of  which  the  first  and  second  extend  the  foot,  and  abduct  it, 
also  causing  its  external  edge  to  look  upwards,  while  the  third  flexes 
the  foot,  but  is  in  other  respects  a  congener  of  the  other  two. 

1.  Peroneus  Longus,  Vide  p.  269 

2.  Peroneus  Brevis,  "     "  269. 

3.  Peroneus  Tertius,  "     "  268. 

Third  Group. 

Two  muscles  situated  along  the  tibia,  one  anterior  and  the  other 
posterior  to  the  interosseous  ligament  ;  the  first  flexes  the  foot,  the 
second  extends  it,  but  both  together  adduct  it,  and  cause  the  internal 
edge  to  look  upwards. 

1.  Tibialis  Anticus,  Vide  p.  267. 

2.  Tibialis  Posticus,  «•     "  274. 

SECOND    CLASS,    TWO    GROUPS. 

First  Group. 

Two  extensors  of  the  toes,  and  flexors  of  the  foot,  situated  ante- 
riorly. 

1.  Extensor  Digitorum  Longus,          Vide  p.  267. 

2.  Extensor  Pollicis  Proprius,  "     "  268. 


DUBLIN    DISSECTOR.  241 

Second  Group. 
Two  flexors  of  the  toes  and  extensors  of  the  foot,  situated  posteriorly. 

1.  Flexor  Longus  Digitorum  Perforans,  Vide  p.  273. 

2.  Flexor  Pollicis  Longus,  "     «  275. 

In  connexion  with  the  different,  varieties  of  club  foot  or  talipes,  we 
find  a  shortening  of  the  tendons  of  these  muscles  on  the  region  of 
the  leg,  the  particular  tendons  affected,  depending  upon  the  particu- 
lar direction  of  the  deformity.  At  first  sight  it  would  appear,  as  if 
certain  muscles  would  be  concerned  in  the  production  of  talipes 
varus,  the  most  common  form,  and  certain  other  muscles,  in  the  pro- 
duction of  talipes  valgus  ;  for  example — in  the  first  case,  the  tibial 
muscles  and  the  flexors  of  the  toes ;  in  the  second  case,  the  two  pero- 
neals,  long  and  short,  &c. :  but  experience  goes  to  prove  that  in  the 
operation  for  club  foot,  it  is  rarely  necessary  to  divide  any  thing  ex- 
cept the  tendo  achillis,  after  which  the  shortening  and  rigidity  of  the 
other  tendons  may  be  overcome  ;  by  the  proper  application  and  con- 
tinuance of  the  machine  and  the  shoe.  Out  of  one  hundred  and 
eighty  cases  of  club  foot,  Dr.  Detmold  found  it  necessary  to  divide 
the  tendo  achillis  alone,  in  one  hundred  and  sixty-lhree,  in  the  other 
seventeen  cases,  it  was  necessary  to  divide  the  tendo  achillis  and 
other  tendons. 

On  the  region  of  the  foot  on  either  side  we  find  twenty  muscles, 
which  all  act  upon  the  phalangeal  bones,  except  the  transversalis 
pedis,  which  acts  rather  upon  the  phalangeal  extremities  of  the  me- 
tatarsal  bones.  These  muscles  are  arranged  in  two  classes,  the  one 
acting  upon  the  toes  generally,  the  other  upon  individual  toes.  In 
the  first  class  are  two  groups,  chiefly  common  extensors,  and  flexors 
of  the  toes :  in  the  second  class  also  are  two  groups,  the  proper  mus- 
cles of  the  great  toe,  and  the  proper  muscles  of  the  little  toe. 

FIRST    CLASS. 

First  Group. 

One  muscle  only,  situated  on  the  superior  or  dorsal  surface  of  the 
foot. 

1.  Extensor  Brevis  Digitorum  Pedis,  Vide  p.  268. 

Second  Group. 

This  group  consists  of  fourteen  muscles,  situated  on  the  plantar 
surface  of  the  foot,  for  the  most  part.  Some  of  them  however,  are 
between  the  metatarsal  bones,  and  may  be  seen  both  on  the  plantar 
and  dorsal  surfaces  of  the  foot,  viz.  the  seven  interossei.  Some  of 
these  muscles  are  single,  while  others  are  manifold,  viz.  the  four  lum- 
bricales  and  seven  interossei. 

1.  Flexor  Brevis  Digitorum  Pedis  Perforatus,  Videp.276. 

2.  Flexor  Digitorum  Pedis  Accessorius,  )  ,7-. »       977 

3.  to  6.  The  Four  Lumbricales,  $  y' 

1.  Transversalis  Pedis,  which  is  somewhat  analogous " 
to  the  palrnaris  brevis  of  the  hand,  except  that  the  lat- 
ter  arches  the  hand  at  the  carpus,  while  the  former  ^Videp.278. 
arches  the  foot  at  the  phalangeal  extremity  of  the 
metatarsus. 

21 


242  DUBLIN    DISSECTOR. 

8  to  14.  The  seven  Interossei,  of  which  four  are  seen*| 
on  the  dorsal  surface  of  the  foot,  three  on  the  plantar 
surface,  and  of  these  last,  the  third  or  most  external,  is  >  Vide  p.  279. 
the  adductor  of  the  little  toe.     All  seven  of  these  mus-  I 
cles  are  adductors  and  abductors  of  the  four  lesser  toes.  J 

SECOND  CLASS. 

First  Group. 

Three  muscles  at  the  under  surface  and  inner  edge  of  the  foot 
which  act  upon  the  great  toe  only. 

1.  Abductor  Pollicis  Pedis,  Vide  p.  276. 

2.  Flexor  Brevis  Pollicis  Pedis,  )  v.fl        _  Q 

3.  Adductor  Pollicis  Pedis,         j^***- " 

Second  Group. 

Two  muscles  at  the  under  surface  and  outer  edge  of  the  foot, 
which  act  upon  the  little  toe  only 

1.  Flexor  Brevis  Minimi  Digiti,  Vide p.%18. 

2.  Abductor  Minimi  Digiti,  to  which  may  be  added  }  y. ,       ^g 
the  third  inferior  interosseous  muscle  under  the  name  of,  > 

3  Adductor  Minimi  Digiti.  )   "     "  280. 

We  find  then  on  taking  a  review  of  all  the  muscles,  which  operate 
directly  on  the  inferior  extremity,  that  there  are  on  the  region  of  the 
hip  anteriorly  and  posteriorly  twelve  muscles  ;  on  the  region  of  the 
thigh,  fifteen,  without  the  subcruralis ;  on  the  region  of  the  leg  twelve ; 
and  on  the  region  of  the  foot  twenty  ;  in  all  fifty-nine  muscles  for 
each  extremity,  or  one  hundred  and  eighteen  for  both.  We  find  too 
that  though  each  muscle  exercises  what  may  be  considered  its  chief 
and  leading  motion,  still  its  action  is  modified  by  its  own  course,  by 
its  combination  with  other  muscles,  and  by  its  own  extent,  as  for  ex- 
ample  we  find  that  when  a  muscle  arises  in  one  region,  and  passes 
over  a  second  to  be  inserted  into  a  third,  it  will  act  upon  both  regions, 
but  produce  a  different  and  opposite  motion  in  the  two  ;  as  in  the 
case  of  the  rectus  femoris,  which  arises  from  the  pelvis,  passes  over 
the  whole  length  of  the  thigh,  and  is  finally  inserted  into  the  leg, 
through  the  patella  and  its  ligament.  The  leading  action  of  this 
muscle  is  to  extend  the  leg  upon  the  thigh,  but  having  done  that  it 
can  then  flex  the  thigh  upon  the  pelvis.  So  too  with  many  other 
muscles  of  the  extremities.] 


SECTION  I. 

DISSECTION    OF    THE    MUSCLES    OF    THE    THIGH. 

PLACE  the  extended  limb  on  the  back  part,  raise  the  in- 
teguments from  the  anterior  and  lateral  parts  of  the  thigh, 


DUBLIN    DISSECTOR.  243 

and  from  the  upper  part  of  the  leg;  several  cutaneous 
nerves,  veins,  and  lymphatic  vessels  are  met  with  in  this 
dissection ;  the  nerves  are  branches  of  the  lumbar  plexus, 
and  of  the  anterior  crural  nerve ;  they  pierce  the  fascia 
lata  near  Poupart's  ligament,  and  descend  chiefly  along  the 
anterior  and  outer  side  of  the  thigh.  The  cutaneous  veins 
are  branches  of  the  internal  saphena  vein ;  this  vessel  will 
be  found,  in  dissecting  the  leg  and  foot,  to  commence  at  the 
inner  side  of  the  latter,  and  to  ascend  along  the  internal 
part  of  the  leg  and  knee  to  the  inner  and  forepart  of  tho 
thigh,  along  which  it  continues  its  course  towards  the 
groin  ;  and  about  an  inch  and  a  half  or  two  inches  below 
Poupart's  ligament  it  pierces  the  fascia  lata,  and  joins  the 
femoral  vein.  In  this  course  the  saphena  vein  receives 
several  cutaneous  branches,  and,  in  general,  just  before  it 
ends  in  the  femoral  it  is  joined  by  one  or  two  large  veins 
from  the  outer  and  forepart  of  the  thigh,  and  by  some 
smaller  branches  from  the  abdominal  parietes ;  some  cu- 
taneous branches  from  the  anterior  crural  and  lumbar 
nerves  accompany  this  vein  in  its  course  along  the  thigh. 
Beneath  the  integuments  the  thigh  is  invested  by  the  su- 
perficial fascia,  which  is  prolonged  around  it  from  the 
parietes  of  the  abdomen ;  in  the  groin  this  fascia  is  thick 
and  laminated,  and  closely  connected  to  the  fascia  lata, 
particularly  to  its  cribriform  portion;  but  inferiorly  and 
posteriorly  it  is  thin  and  loose,  and  differs  but  little  from 
the  ordinary  sub-cutaneous  cellular  tissue.  This  fascia 
may  be  easily  detached  from  the  fascia  lata  of  the  thigh, 
except  in  the  groin  ;  in  attempting  to  raise  it  in  this  region 
we  expose  the  superficial  inguinal  ganglia  ;  these  are  eight 
or  ten  in  number :  five  or  six  of  them  are  placed  parallel 
to  Poupart's  ligament,  some  above,  others  below  it ;  two  or 
three  are  situated  lower  down  in  the  groin  than  these,  near 
the  termination  of  the  saphena  vein  ;  these  last  ganglia  lie 
on  the  fascia  lata ;  they  are  larger  than  the  former,  and 
are  parallel  to  the  saphena  vein.  Through  these  conglo- 
bate inguinal  ganglia  the  superficial  absorbents  of  the  low- 
er extremities  pass ;  also  those  from  the  external  parts  of 
generation.  Beneath  the  fascia  lata,  and  close  to  the  fe- 
moral vessels,  are  the  deep-seated  inguinal  ganglia ;  they 
are  small,  and  only  three  or  four  in  number;  the  deep- 
seated  absorbents  of  the  limb  pass  through  these.  The  in- 
teguments and  superficial  fascia  having  been  removed,  the 
fascia  lata  may  be  next  examined.  This  aponeurosis  sur- 
rounds the  thigh  ;  it  is  very  strong  and  tendinous  external- 
ly, but  so  thin  and  weak  internally,  that  without  caution  it 
is  apt  to  be  removed  along  with  the  integuments ;  it  is  at- 
tached superiorly  and  externally  to  the  crest  of  the  ilium  ; 


244  DUBLIN    DISSECTOR. 

posteriorly  to  the  sacrum  and  coccyx :  on  the  glutseus  max- 
imus  it  is  very  weak  and  thin,  but  at  the  anterior  border  of 
this  muscle  it  becomes  very  strong,  receiving  an  addition 
of  fibres,  both  from  the  tendon  of  that  muscle,  and  from 
the  tensor  vaginae  femoris ;  anteriorly  the  fascia  lata  is  at- 
tached  to  Poupart's  ligament,  and  internally  to  the  rami  of 
the  ischium  and  pubis ;  as  this  aponeurosis  extends-  down 
the  thigh,  it  confines  the  different  muscles  in  their  situation, 
so  as  to  preserve  the  figure  of  the  limb  ;  several  processes 
also  pass  in  from  its  internal  surface  to  form  septa  and 
sheaths  for  some  muscles,  and  to  bind  down  others  in  their 
place ;  to  many  of  these  processes  the  muscles  adhere,  so 
that  when  in  action  they  serve  to  make  the  fascia  more 
tense  and  resisting ;  these  processes  also  serve  to  increase 
the  surface  of  origin  or  attachment  of  several  muscles. 
Along  the  posterior  part  of  the  thigh  the  fascia  lata  is.  con- 
nected to  the  whole  length  of  the  linea  aspera,  also  to  the 
insertion  of  the  glutasus  maximus,  and  to  the  origin  of  the 
short  head  of  the  biceps  ;  inferiorly  it  adheres  to  the  con- 
dyles  of  the  femur,  surrounds  the  knee-joint,  and  receives 
an  addition  of  fibres  from  the  different  tendons  in  this  re- 
gion ;  below  the  knee  it  is  continued  over  the  heads  of  the 
tibia  and  fibula  into  the  fascia  of  the  leg.  Numerous  fora- 
mina are  observable  in  the  fascia  lata,  particularly  at  the 
upper  and  anterior  part  of  the  thigh  ;  they  transmit  cuta- 
neous nerves  and  vessels:  the  most  remarkable  of  these 
holes  is  that  for  the  saphena  vein ;  it  is  situated  about  an 
inch  and  a  half  or  two  inches  below  Poupart's  ligament, 
and  may  be  most  distinctly  seen  by  dividing  the  vein  on 
the  forepart  of  the  thigh,  and  raising  it  towards  the  abdo- 
men ;  this  opening  is  semilunar,  the  concavity  directed  up- 
wards ;  from  its  apparently  sharp  edge  the  fascia  is  reflect- 
ed backwards,  and  is  lost  on  the  sheath  of  the  femoral  ves- 
sels. That  part  of  the  fascia  which  is  internal  to  this  open- 
ing is  named  the  pubic  portion  of  the  fascia  lata ;  it  covers 
the  pectinseus  muscle,  adheres  to  the  spine  and  linea  in- 
nominata  of  the  pubis,  extends  behind  the  femoral  vessels, 
and  is  continuous  with  the  fascia  iliaca ;  that  part  of  the 
fascia  lata  external  to  the  saphenic  opening  is  called  the 
iliac  portion ;  it  covers  the  sartorious,  tensor  vaginse,  rec- 
tus,  and  iliacus  internus  muscles,  and- is  continued  ob- 
liquely in  front  of  the  femoral  vessels,  in  the  form  of  a  cre- 
scentic  or  falciform  process,  the  concavity  of  which  is  direct- 
ed downwards  and  inwards ;  the  convexity  is  towards  the 
ilium,  and  attached  to  Poupart's  ligament ;  the  lower  -cornu 
of  this  crescentic  process  is  continuous  with  the  outer  cor- 
nu of  the  saphenic  opening,  and  the  upper  cornu  extends 
in  front  of  the  femoral  vessels  to  their  inner  side,  and  is 


DUBLIN    DISSECTOR.  245 

inserted  along  with  the  third  insertion  of  Poupart's  liga- 
ment, or  Gimbernaut's  ligament,  into  the  linea  innominata, 
or  ilio  pectinaea.  Between  the  margin  of  the  falciform 
process  and  the  pubic  part  of  the  fascia  lata  is  a  thin  mem- 
brane, perforated  by  numerous  vessels,  this  is  termed  the 
cribriform  fascia,  it  is  connected  on  either  side  to  the  iliac 
and  pubic  portions  of  the  fascia  lata,  and  extends  from  the 
saphena  vein  to  Poupart's  ligament,  in  front  of  the  femoral 
vessels ;  it  adheres  to  the  anterior  part  of  the  sheath  of  the 
latter,  or  to  the  fascia  transversalis ;  when  this  cribriform 
fascia  is  removed,  the  falciform  process  is  made  more  dis- 
tinct.— (See  Description  of  Crural  Hernia,  page  150.)  The 
fascia  lata,  in  some  situations,  particularly  along  the  outer 
side  of  the  lirnb,  is  seen  to  consist  of  two  laminae  of  fibres  ; 
the  external  take  a  circular,  the  internal  a  longitudinal  di- 
rection ;  these  two  laminae  are  very  distinctly  separated  at 
the  upper  and  outer  part  of  the  thigh  by  the  insertion  of 
the  tensor  vaginas  femoris ;  the  deep  layer,  which  in  this 
situation  is  very  strong,  is  attached  to  the  capsular  liga- 
ment of  the  hip  joint,  and  to  the  external  head  of  the  rec- 
tus  muscle, — Raise  the  fascia  lata  from  the  anterior  and 
lateral  parts  of  the  thigh,  several  muscles  will  come  into 
view,  the  femoral  vessels  also  in  the  groin  will  be  partially 
exposed,  they  are  still  somewhat  concealed  by  a  quantity 
of  adipose  substance,  and  by  a  few  deep-seated  lymphatic 
ganglia ;  when  these  are  removed,  we  always  find  the  vein 
internal  to  the  artery,  and  about  an  inch  and  a  half  from 
the  spine  of  the  pubis;  immediately  external  to  the  vein  is 
the  artery  resting  on  the  psoas,  and  about  a  quarter  of  an 
inch  external  to  the  artery  is  the  anterior  crural  nerve,  im- 
bedded between  the  psoas  and  i'liacus,  and  covered  by  the 
fascia  iliaca,  it  does  not,  therefore,  lie  in  the  sheath  of  the 
vessels.  Clean  the  several  muscles  which  now  partially 
appear  on  the  forepart  of  the  thigh ;  external  to  the  ves- 
sels, the  sartorius  and  tensor  vaginae  are  first  seen  ;  inter- 
nal to  the  vessels  are  the  pectinaeus,  graoilis,  and  the  three 
adductors,  and  immediately  covering  the  anterior  and 
lateral  parts  of  the  femur  are  the  rectus,  erurseus,  vastus 
internus,  and  externus. 

MUSCLES   ON   THE   FOREPART    AND   SIDES   OF   THE   THIGH. 

These  are  eleven  in  number. 

1.  TENSOR  VAGINAE  FEMORIS,  at  the  upper  and  outer  part 
of  the  thigh,  narrow  above,  broad  and  thin  below,  arises 
tendinous  and  fleshy  from  the  external  part  of  the  anterior 
superior  spinous  process  of  the  ilium ;  it  forms  a  fleshy 
belly,  which  descends  obliquely  backwards,  and  is  inserted, 
broad  and  thin,  into  a  duplicature  of  the  fascia  lata  on  the 
21* 


246  DUBLIN    DISSECTOR, 

outside  of  the  thigh,  about  three  inches  below  the  great 
trochanter ;  use,  to  make  tense  the  fascia,  to  rotate  the  thigh 
inwards ;  also,  to  assist  in  flexing  and  abducting  it.  The 
origin  of  this  muscle  is  between  the  sartorius  and  gluteeus 
medius  :  between  these  muscles  it  descends,  covered  by  the 
fascia  lata ;  its  insertion  is  anterior  to  that  of  the  glutseus 
maximus  muscle. 

2.  SARTORIUS  is  the  longest  muscle  in  the  body,  thin  and 
flat  like  a  ribband,  broader  in  the  middle  than  at  the  ex- 
tremities, situated  obliquely  along  the  anterior  and  inner 
side  of  the  thigh,  arises  by  short  tendinous  fibres  from  the 
anterior  superior  spine  of  the  ilium,  and  from  the  notch 
below  that  process,  it  soon  becomes  broad  and  fleshy,  ex- 
tends obliquely  across  the  thigh  to  its  inner  side,  and  de- 
scending perpendicularly  to  the  knee  passes  behind  the 
condyle  of  the  femur  ;  it  then  turns  forwards  and  outwards 
towards  the  inner  side  of  the  upper  end  of  the  tibia,  into 
which  it  is  inserted  below  the  tubercle,  by  a  long  flat  tendon, 
the  anterior  edge  of  which  is  attached  to  the  fascia  lata 
covering  the  knee-joint,  and  the  posterior  edge  sends  off' an 
aponeurosis  to  the  fascia  of  the  leg.  Use,  to  flex  the  leg 
upon  the  thigh,  also  the  latter  on  the  pelvis;  to  adduct  the 
thigh  and  leg  obliquely,  so  as  to  cross  the  lower  extremi- 
ties ;  when  the  thigh  and  leg  arc  extended,  it  assists  in  rais- 
ing and  advancing  forwards  the  whole  limb,  also  in  turning 
the  knee  outwards  ;  in  standing,  it  also  supports  the  pelvis 
and  prevents  it  bending  backwards  on  the  thigh.  This 
muscle  through  its  whole  extent  is  covered  only  by  the 
fascia  lata  and  the  integuments,  its  superior  extremity  lies 
between  the  tensor  vaginse  and  the  iliacus  internus  mus- 
cles ;  its  inferior  extremity  expands  into  a  strong  aponeu- 
rosi.s,  which  covers  and  adheres  to  the  tendons  of  the  semi- 
tendinosus  and  gracilis  muscles,  anterior  and  superficial 
to  both  of  which  it  is  inserted  ;  in  its  course  along  the  thigh 
it  first  passes  over  the  psoas,  iliacus,  and  rectus  muscles, 
next  over  the  vastus  internus  and  adductor  muscles  and 
the  femoral  vessels,  from  which  it  is  separated  by  a  strong 
aponeurosis;  iriferiorly  it  passes  over  the  internal  lateral 
ligament  of  the  knee,  between  the  tendons  of  the  adductor 
magnus  and  the  gr-acilis.  The  superior  third  of  this  mus- 
cle extends  in  an  oblique  direction  from  the  ilium  down- 
wards and  inwards,  forms  the  external  boundary  of  the  in- 
guinal region,  and  lies  to  the  outer  side  of  the  femoral  ves- 
sels ;  the  middle  third  is  more  vertical  in  its  course,  and  is 
here  about  two  inches  broad,  and  completely  covers  the 
femoral  vessels,  also  a  part  of  the  adductor,  and  vastus  in- 
ternus muscles. 

[Varieties.       Meckel  saw  one  subject  in  which  this  muscle  was 


DUBLIN    DISSECTOR.  247 

wanting.     In  the  negro,  it  is  sometimes  found  unusually  broad,  and 
sometimes  it  presents  a  middle  tendon.] 

3.  RECTUS  FEMORIS,  long  and  flat,  rather  round  in  the 
centre,  placed  vertically  on  the  forepart  of  the  thigh,  arises 
by  two  tendons,  one  short,  strong,  anterior  and  internal, 
from  the  anterior  inferior  spinous  process  of  the  ilium,  the 
other  longer,  broader,  and  more  curved  from  the  superior 
and   external   border   of  the   acetabulum,   and   from   the 
capsular  ligament ;  these  tendons  soon  uniting  form  a  strong 
fleshy  belly,  which  descends  almost  vertically,  with  a  slight 
inclination  inwards;  this  muscle  has  a  peculiar  penniform 
appearance,  it  is  also  tendinous  anteriorly  in  the  upper 
half,  so  that  the  sartorius  can  glide  over  it,  and  tendinous 
posteriorly  in  the  lower  half,  whereby  it  can  move  on  the 
surface  of  the  crurceus.     This  muscle  ends  in  a  flat  ten- 
don, which  is  inserted  along  with   the  vasti  and  cruraeus 
into  the  upper  edge  of  the  patella,  a  few  fibres  pass  ante- 
rior to  this  bone,  and  are  continued  into  the  ligamentum 
patellae,  which  descends  obliquely  outwards  to  the  tuber- 
cle of  the  tibia.     Use,  to  extend  the  leg  on  the  thigh,  and 
to  flex  the  thigh  on  the  pelvis ;  it  also  supports  and  draws 
forwards  the  pelvis  on  the  thigh,  and  strengthens  the  cap- 
sular ligament  of  the  hip  joint.     The  anterior  tendinous 
origin  of  this  muscle  is  covered  by  the  sartorius,  tensor 
vaginse,  and  iliacus  internus  muscles,  the  posterior  by  the 
glutseus  medius  and  minimus  muscles;  the  remainder  of  the 
muscle  is  only  covered  by  the  integuments  and  fascia ;  su- 
periorly this  muscle  lies  on  the  capsular  ligament  of  the 
hip  joint  and  the  external  circumflex  vessels;  in  the  rest 
of  its  course  on  the  crurseus  and  vasti  muscles,  to  which  it 
is  united  below,  so  that  some  describe  these  four  as  one. 
muscle,  under  the  name  of  quadriceps  extensor  cruris.     Be- 
neath the  rectus  we  find  this  large  mass  of  muscular  sub- 
stance, covering  the  front  and  sides  of  the  femur ;  it  may 
be  divided  superiorly  into   three   portions,  but  infcriorly 
these  are  inseparably  united ;  the  external  portion  is  nam- 
ed vastus  externus,  the  internal,  vastus  internus,  and  the 
middle,  crurssus. 

4.  VASTUS  EXTERNUS,  much  larger  than  the  other  portions, 
and  larger  above  than  below,  arises  tendinous  and  fleshy 
from  the  root  and  anterior  part  of  the  great  trochanter,  an- 
terior to  the  tendon  of  the  glu'toeus  maxlmus,  from  the  outer 
edge  of  the  linea  aspera,  its  whole  length,  and  from  the 
oblique  ridge  which  leads  to  the  external  condyle,  anterior 
to  the  short  head  of  the  biceps ;  from  all  the  external  sur- 
face of  the  bone,  and  from  the  fascia  lata,  the  fibres  des- 
cend obliquely  forwards;  the  superior  are  very  long,  the 
inferior  are  shorter  and  more  transverse,  inserted  into  the 


248  DUBLIN    DISSECTOR. 

external  surface  of  the  tendon  of  the  rectus,  also  into  the 
side  of  the  patella,  and  by  an  aponeurosis,  which  adheres 
to  the  synovial  membrane  of  the  knee-joint,  into  the  head 
of  the  tibia.  Use,  to  extend  the  knee,  also  to  rotate  the  leg 
outwards ;  this  muscle  is  partly  concealed  by  the  rectus ; 
its  external  surface  is  tendinous  above  and  fleshy  below, 
its  internal  is  fleshy  above  and  tendinous  below. 

5,  VASTUS  INTERNUS,  smaller  and  shorter  than  the  last, 
arises  on  the  anterior  part  of  the  femur,  from  the  inter-tro- 
chanteric  line ;  from  the  inner  edge  of  the  linea  aspera,  its 
whole  length,  also  from  the  inner  side  of  the  femur,  the 
fibres  descend  obliquely  forwards,  and  are  inserted  into  the 
inner  edge  of  the  tendon  of  the  rectus,  also  into  the  patel- 
la, and  by  an  aponeurosis,  which  covers  the  inner  side  of 
the  synovial  membrane  of  the  knee,  into  the  head  of  the 
tibia.     Use,  to  extend  the  knee  and  turn  the  leg  a  little  in- 
wards.   The  vastus  internus  is  partly  concealed  by   the 
rectus  and  sartorius,  its  origin  lies  anterior  to  the  insertion 
of  the  psoas,  pectinceus,  and  adductor  muscles,  and  over- 
laps the  cruraus,  so  as  to  be  in  contact  with  the  vastus  ex- 
ternus ;  its  internal  surface  is  tendinous  above  and  fleshy 
below  ;  an  aponeurosis  from  the  two  vasti  covers  the  patel- 
la and  its  ligament,  also  the  sides  of  the  joint ;  this  apone- 
rosis  is  inserted  into  the  head  of  the  tibia,  it  serves  to  sup- 
port the  patella  in  its  situation,  and  to  protect  the  sides  of 
the  articulation  like  a  capsular  ligament ;  a  small  bursa  is 
situated  over  the  patella,  between  this  aponeurosis  and  the 
skin  ;  the  insertion  of  the  vastus  externus  into  the  patella 
overlaps  that  of  the  vastus  internus,  and  both  overlap  the 
crurseus,  from  which  the  vastus  externus  can  be  more  easi- 
ly separated  above,  but  the  vastus  internus  below. 

6.  CKURVEUS,  shorter  than  either  of  the   vasti,  between 
which  it  lies,  larger  and  more  tendinous  below  than  above, 
arises  fleshy  from  the  anterior  and  external  part  of  the  fe- 
mur, commencing  at  the  inter-trochanteric  line,   and  ex- 
tending along  three-fourths  of  the  bone,  as  far  outwards  as 
the  linea  aspera  ;  it  does  not  adhere  to  the  inner  side  of 
the  femur,  there  being  a  portion  of  the  latter,  nearly  an 
inch  in  breadth  and  extending  almost  the  whole  length  of 
the  bone,  to  which  no  muscular  fibre  adheres  ;  the  crurceus 
descends  close  to  the  femur  to  its  inferior  third,  the  fibres 
then  incline  forwards,  become  tendinous  posteriorly,  and 
are  separated  from  the  bone  by  a  large  bursa,  and  by  a 
considerable  quantity  of  fat ;  inserted  into  the  upper  and 
outer  edge  of  the  patella,  also  into  the  synovial  membrane 
of  the  knee  behind  the  vasti,  particularly  the  external,  to 
which  it  is  here  intimately  united.     Use  to  assist  the  vasti 
and  the  rectus  in  extending  the  leg.    This  muscle  is  cover- 


DUBLIN    DISSECTOR.  249 

ed  by  the  rectus  and  the  vasti,  from  the  latter  it  can  only 
be  separated  superiorly  by  tearing  a  few  muscular  fibres, 
and  tracing  some  large  nerves  and  vessels  that  pass  be- 
tween them.  The  large  bursa,  which  is  situated  behind 
the  lower  part  of  this  muscle,  is  attached  to  and  frequently 
communicates  with  the  synovial  membrane  of  the  joint;  a 
few  muscular  fibres  are  generally  attached  to  this  mem- 
brane, and  have  been  described  as  a  distinct  muscle,  the 
SUB-CRURAL  or  CAPSULAR,  this  arises  from  the  anterior  sur- 
face of  the  femur,  about  its  inferior  fourth,  passes  forwards 
and  downwards,  and  is  inserted  into  the  synovial  mem- 
brane. Use,  to  raise  the  synovial  membrane  in  extension 
of  the  leg,  so  as  to  prevent  its  being  contused  by  the  pa- 
tella. 

7.  GRACILIS,  flat,  long,  and  thin,  broad  and  fleshy  above, 
round  and  tendinous  below,  situated  at  the  inner  side  of  the 
thigh,  immediately  beneath  the  integuments  and  fascia  ; 
arises  by  a  thin  short  tendon  from  the  lower  half  of  the 
symphysis,  and  from  the  inner  edge  of  the  descending  ra- 
mus  of  the  pubis  ;  it  soon  becomes  fleshy,  and  descends  ver- 
tically, one  edge  directed  forwards,  the  other  backwards, 
and  its  surfaces  looking  one  inwards,  the  other  outwards  ; 
about  the  inferior  fifth  of  the  thigh  it  ends  in  a  round  ten- 
don which  passes  behind  the  inner  condyle,  and  then  turns 
forwards  along  with  the  tendon  of  the  sartorius.  behind  and 
beneath  which  it  lies  ;  inserted  into  the  superior  part  of  the 
internal  surface  of  the  tibia,  uniting  with  the  sartorius  and 
semi-tendinosus,  but  superficial  to  the  latter.  Use,  to  adduct 
the  leg  and  thigh,  to  bend  the  knee,  and  turn  the  leg  and 
foot  inwards.  The  origin  of  the  gracilis  is  between  the 
triceps  and  the  cms  penis ;  its  whole  course  is  superficial, 
except  near  the  knee,  where  it  is  covered  by  the  sartorius  ; 
its  insertion  is  inferior  to  that  of  the  sartorius,  and  superior 
to  that  of  the  semi-tendinosus  ;  the  saphena  vein  and  nerve 
are  situated  between  its  tendon  and  that  of  the  sartorius  at 
the  inner  side  of  the  knee,  but  these  are  separated  from 
each  other  by  a  fascia,  which  attaches  these  tendons  toge- 
ther, the  vein  lying  superficial :  from  the  tendon  of  the  gra- 
cilis an  aponeurosis  is  sent  off  to  the  fascia  of  the  leg. 

a  PECTIN^EUS,  flat,  triangular,  broad  above,  situated  at 
the  superior,  anterior,  and  internal  part  of  the  thigh  ;  arises 
fleshy  from  the  linea  innominata  and  the  concave  surface 
below  it  on  the  horizontal  rarnus  of  the  pubis,  between  the 
spine  of  that  bone  and  the  ilio-pectina3al  eminence ;  it 
forms  a  flat  fleshy  belly,  which  descends  obliquely  out- 
wards and  backwards,  and  is  inserted  by  a  flat  tendon  into 
the  rough  ridge  which  leads  from  the  lesser  trochanter  to 
the  linea  aspera.  Use,  to  adduct  and  flex  the  thigh,  also, 


250  DUBLIN    DISSECTOR. 

to  rotate  it  outwards ;  it  may  also  serve  to  strengthen  the 
capsular  ligament  of  the  hip  joint  internally,  and  in  ad- 
duction of  the  limb  to  draw  the  capsule  inwards  from  be- 
tween the  neck  of  the  femur  and  the  acetabuluin.  The 
pectinseus  lies  between  the  psoas  magnus  and  the  adductor 
longus;  the  latter  overlaps  it;  it  is  covered  superiorly  by 
the  fascia  lata,  and  inferiorly  by  the  femoral  vessels ;  it 
covers  the  obturator  nerve  and  vessels,  the  external  obtura- 
tor muscle,  and  the  adductor  brevis  ;  it  also  adheres  to  the 
capsular  ligament  of  the  hip  joint. 

[Variety.  A  fissure  sometimes  divides  this  muscle  into  two,  of 
which  the  lower  part  is  the  smallest.] 

TRICEPS  ADDUCTOR  FEMORIS  consists  of  three  portions, 
which  pass  in  distinct  laminas  from  the  pelvis  to  the  thigh. 

9.  ADDUCTOR  LONGUS,  flat  and  triangular,  broad  below", 
is  situated  at  the  upper  and  internal  part  of  the  thigh,  su- 
perficial to  the  other  adductors  and  to  the  pectinseus ;  it 
arises  by  a  short,  small,  but  strong  tendon  from  the  anterior 
surface  of  the  pubis,  between  its  spine  and  the  symphysis ; 
this  ends  in  a  broad  fleshy  belly,  which  descends  obliquely 
backwards  and  outwards,  and  is  inserted  by  a  broad  thin 
tendon  into  the  middle  third  of  the  linea  aspera,  between 
the   adductor  magnus  and  the  vastus  internus,  to  both  of 
which  it  is  closely  united.     The  origin  of  this  muscle  lies 
between  the  pectinceus  and  the  gracilis,  and  above  the  ad- 
ductor  brevis ;  its   insertion  is  behind  the  vastus  internus, 
and  in  front  of  the  adductor  magnus ;  this  adductor  is  co- 
vered by  the  integuments  and  fascia  superiorly,  and  by  the 
sartorius  and  the  femoral  vessels  inferiorly  ;  it  lies  anterior 
to  the  two  following  muscles. 

[Varieties.  This  muscle  is  sometimes  divided  into  two,  by  a  fis- 
sure, and  sometimes  its  insertion  extends  lower  down  than  above  de- 
scribed, by  its  tendon  running  into  that  of  the  adductor  magnus.] 

10.  ADDUCTOR  BREVIS,  short,  flat,  and  triangular,  is  situ- 
ated   posterior    to  the  adductor  longus    and    pectinseus, 
and  internal  to  the  psoas  ;  arises  flat  and  tendinous  from  the 
anterior  inferior  surface  of  the  pubis,  between  the  gracilis 
muscle,  the  symphysis  pubis,  and  the  thyroid  hole  ;  it  soon 
ends  in  a  fleshy  belly,  which  passes  outwards,  backwards, 
and  a  little  downwards,  inserted  by  tendinous  slips  into  the 
superior  third  of  the  internal  root  of  the  linea  aspera,  ex- 
tending for  about  three  inches  below  the  lesser  trochanter. 
The  origin  of  this  muscle  is  external  to  the  gracilis,  and 
concealed  by  the  adductor  longus  and  the  pectinceus ;  as  it 
descends  it  is  covered  by  these  muscles,  except  a  small  por- 
tion near  its  insertion,  which  appears  between  them ;  this 
portion  is   posterior  to  the  femoral  and  prof  unda  vessels  ; 


DUBLIN    DISSECTOR.  251 

its  insertion  is  anterior  to  that  of  the  adductor  magnus  ;  in 
the  tendon  of  this  adductor  one  or  two  large  openings  fre- 
quently exist  for  the  passage  of  some  of  the  perforating 
arteries. 

[Variety.  This  muscle  also  is  sometimes  divided  into  two  by  a 
fissure,  which  according  to  Meckel,  is  analogous  to  the  same  muscle 
in  the  ape.  The  same  is  also  true  of  the  next  muscle.] 

11.  ADDUCTOR  MAGNUS,  the  longest  and  largest  of  the  ad- 
ductors, triangular,  the  base  attached  to  the  femur,  the 
apex  to  the  pelvis ;  arises  chiefly  fleshy  from  the  anterior 
surface  of  the  descending  ramus  of  the  pubis,  external  to 
the  gracilis,  also  from  the  ramus  of  the  ischium,  and  ten- 
dinous from  the  external  border  of  the  tuberosity  of  the 
latter ;  the  fibres  pass  outwards  with  different  degrees  of 
obliquity ;  those  which  arise  from  the  pubis  ascend  ob- 
liquely outwards,  those  from  the  ramus  of  the  ischium  pass 
outwards  and  downwards,  and  those  from  the  tuber  ischii 
more  directly  downwards ;  inserted  fleshy  into  the  rough 
ridge  which  leads  from  the  great  trochanter  to  the  linea  as- 
pera, tendinous  and  fleshy  into  the  linea  aspera,  and  by  a 
long  round  tendon  into  the  internal  condyle  of  the  femur. 
The  superior  edge  of  this  muscle  has  a  twisted  appearance, 
it  is  nearly  parallel  to  the  quadratus  femoris ;  several 
branches  of  the  internal  circumflex  vessels  pass  between 
these  muscles,  and  in  rotation  of  the  leg  inwards  the  lesser 
trochanter  projects  between  them;  the  middle  portion 
which  is  inserted  into  the  linea  aspera,  is  internal  to  the  in- 
sertion of  the  glutseus  maximus,  and  to  the  origin  of  the 
short  head  of  the  biceps.  This  part  of  the  muscle  is  per- 
forated by  several  branches  of  the  perforating  arteries ;  at 
the  lower  part  of  the  linea  aspera  this  muscle  appears  to 
separate  into  two  portions,  one  of  which  is  inserted  into 
the  linea  aspera,  between  the  vastus  internus  and  the  short 
head  of  the  biceps ;  the  other  is  continued  into  the  long 
tendon  which  is  inserted  into  the  inner  condyle.  The  ad- 
ductor magnus  is  covered  internally  by  the  gracilis,  and 
anteriorly  by  the  long  and  short  adductors,  the  pectinseus, 
part  of  the  sartorius,  and  the  femoral  vessels ;  posterior  to 
it  are  the  sciatic  nerve,  and  the  hamstring  muscles  ;  the 
tendinous  insertion  of  the  lower  part  of  this  muscle  is  in- 
timately connected  to  the  vastus  internus  :  about  the  infe- 
rior fourth  of  the  thigh  there  is  a  large  oblique  opening  be- 
tween these  two  muscles,  through  which  the  femoral  ves- 
sels pass  into  the  poplitseal  space,  Use,  the  three  adduc- 
tors, in  addition  to  adducting  the  limb,  can  rotate  it  out- 
wards ;  they  also  serve  to  steady  and  support  the  pelvis  on 
the  thigh ;  the  long  and  short  adductors  can  also  flex  the 


252  DUBLIN    DISSECTOR. 

thigh  on  the  pelvis,  and  the  adductor  magnus  can  extend 
it,  when  it  has  been  flexed. 

In  dissecting  the  preceding  muscles,  we  observe  the  fol- 
lowing vessels  and  nerves. 

The  Femoral  Artery  passes  from  under  Poupart's  ligament 
about  midway  between  the  symphysis  pubis  and  the  spine 
of  the  ilium  ;  it  thence  descends  obliquely  inwards  and 
backwards,  and  about  the  lower  part  of  the  middle  third 
of  the  thigh  it  perforates  the  tendon  of  the  adductor  mag- 
nus, enters  the  poplitoeal  space,  and  then  receives  the  name 
of  poplitseal  artery.  In  the  upper  third  of  the  thigh,  or  in 
the  inguinal  region,  the  artery  is  covered  only  by  the  skin, 
superficial  fascia,  some  lymphatic  ganglia,  and  the  fascia 
lata ;  in  the  middle  third  of  the  thigh  it  receives  the  addi- 
tional covering  of  the  sartorius,  and  beneath  this  of  a  very 
strong  tendinous  aponeurosis,  which  passes  from  the  ten- 
dons of  the  adductor  longus  and  magnus  over  the  artery 
and  vein,  and  joins  the  tendon  of  the  vastus  internus ;  in 
this  part  of  the  thigh  the  artery  is  enclosed  in  a  perfect 
tendinous  sheath,  consisting  anteriorly  of  the  aponeurosis 
just  mentioned,  posteriorly  and  internally  of  the  tendons 
of  the  adductors,  and  externally  of  the  vastus  internus : 
at  the  lower  end  of  the  sheath  the  artery  passes  into  the 
ham  through  a  large  oval  opening  which  is  bounded  supe- 
riorly by  the  adductor  longus  and  magnus,  externally  by 
the  vastus  internus,  internally  by  the  adductor  magnus, 
and  inferiorly  by  the  united  tendons  of  the  adductor  mag- 
nus and  vastus  internus.  The  femoral  artery  in  this  course 
first  passes  over  a  few  fibres  of  the  psoas,  next  over  the 
pectinseus  and  adductor  brevis,  the  adductor  longus,  and  a 
small  portion  of  the  magnus. 

The  femoral  artery,  immediately  below  Poupart's  liga- 
ment, gives  offi  1st,  some  cutaneous  branches ;  2nd,  small 
arteries  to  the  inguinal  ganglia;  3rd,  about  two  inches  be- 
low Poupart's  ligament,  a  very  large  branch,  the  profunda  i 
4th,  several  muscular  branches  to  the  sartorius  and  vastus 
internus ;  and  5th,  just  before  it  enters  the  ham  the  anasto- 
motica  magna,  which  is  distributed  to  the  muscles  and  inte- 
guments at  the  inner  side  of  the  knee.  The  profunda  is  the 
largest  branch  of  the  femoral ;  it  descends  behind  that  ves- 
sel and  to  its  inner  side,  and  gives  several  branches  to  the 
muscles  of  the  thigh,  namely,  the  external  and  internal  cir- 
cumflex, and  the  three  or  four  perforating  arteries.  (See 
Anatomy  of  the  Vascular  System.)  The  femoral  vein  takes 
the  same  course  as  the  artery  ;  in  the  groin  it  always  lies 
to  its  internal  or  pubic  side,  but  as  it  descends  it  becomes 
posterior  to  it.  In  dissecting  the  muscles  on  the  fore  part 
of  the  thigh,  numerous  branches  of  the  anterior  crural  nerve 


DUBLIN    DISSECTOR.  253 

are  met  with  ;  this  nerve  in  the  groin  is  separated  into  se- 
veral branches,  many  of  these  become  cutaneous,  others 
pass  to  the  muscles  on  the  fore  part  of  the  thigh,  and  two 
or  three  accompany  the  femoral  artery ;  one  of  these,  the 
nervus  saphenus,  enters  its  tendinous  sheath,  and  descending 
along  the  fore  part  of  the  artery,  as  far  as  the  opening  in 
the  tendon  of  the  triceps,  then  leaves  that  vessel,  descends 
between  the  tendons  of  the  sartorius  and  gracilis  muscles 
to  the  inner  side  of  the  knee ;  it  there  becomes  cutaneous, 
and  attaching  itself  to  the  saphena  vein,  it  accompanies 
this  vessel  along  the  inner  side  of  the  leg  to  the  internal 
ankle. — (See  Anatomy  of  the  Nervous  System.) 


SECTION  II. 


DISSECTION    OF    THE    POSTERIOR    PART    OF    THE    THIGH. 

PLACE  the  detached  extremity  on  its  fore  part,  with  a 
block  beneath  the  hip  joint,  so  as  to  flex  the  latter  slightly, 
and  thus  extend  the  muscles  in  this  region.  Raise  the  inte- 
guments from  the  posterior  surface  of  the  limb,  from  the 
crest  of  the  ilium  to  the  calf  of  the  leg ;  the  cutaneous 
nerves  which  are  met  with  in  this  dissection  are  branches 
from  the  lumbar  nerves,  from  the  sacral  plexus,  and  from 
the  sciatic  nerve.  The  cutaneous  veins  pass  in  different 
directions,  some  turn  round  the  inner  side  of  the  limb  to 
the  saphena  vein,  others  penetrate  between  the  muscles, 
and  join  the  deep  veins  which  accompany  the  muscular  or 
the  perforating  arteries,  and  others  descend  to  the  popliteal 
space,  and  join  the  popliteal  or  the  lesser  saphena  vein. 
The  fascia  lata  over  the  glutaeus  maximus  is  weak,  but  an- 
terior to  that  muscle,  that  is,  covering  the  glutseus  medius, 
it  is  very  strong  and  adheres  to  the  surface  of  this  muscle, 
and  to  the  crest  of  the  ilium  above  it ;  on  the  posterior  part 
of  the  thigh,  the  fascia  is  not  so  dense  as  on  the  outer  or 
anterior  part ;  inferiorly,  over  the  popliteal  region,  or  the 
ham,  it  is  much  stronger  than  above ;  from  the  thigh  it  is 
continued  over  the  muscles  of  the  leg,  in  which  situation  it 
may  be  examined  afterwards :  the  fascia  and  integuments 
being  removed,  the  muscles  should  be  cleanly  dissected ; 
these  may  be  divided  into  the  muscles  of  the  hip  and  of  the 

22 


254  DUBLIN    DISSECTOR. 

DISSECTION    OF   THE   MUSCLES    OF   THE   HIF. 

These  are  nine  in  number,  viz.  the  three  glutsei,  the  pyri- 
formis,  the  gemini,  the  two  obturator,  and  the  quadrator 
femoris. 

1.  GLUTJEUS  MAXIMUS  covers  the  greater  part  of  the  pel- 
vis, also  the  upper  part  of  the  thigh  ;  it  is  somewhat  square, 
one  edge  being  the  origin  and  attached  to  the  sacrum,  the 
opposite  edge  or  the  insertion  to  the  femur,  and  to  the  fas- 
cia lata,  the  other  edges  are  directed  one  upwards  and  for- 
wards, the  other  downwards  and  backwards.  The  inferior 
edge  is  thick  and  round,  and  covered  by  a  great  quantity 
of  fat ;  this  forms  the  fold  of  the  nates.  It  is  difficult  to 
clean  the  surface  of  the  glutseus  maximus,  its  fasciculi  are 
so  coarse  and  rough,  this  may  be  facilitated  by  dissecting 
parallel  to  the  fibres,  that  is,  in  a  line  drawn  from  the  sa- 
crum towards  the  great  trochanter.  This  muscle  arises 
by  fleshy  and  short  aponeurotic  fibres,  from  the  posterior 
fi'fth  of  the  crest  of  the  ilium,  from  the  rough  surface  be- 
tween the  crest  and  the  superior  semicircular  ridge  on  this 
bone,  from  the  posterior  sacro-iliac  ligaments  and  lumbar 
fascia,  from  the  tubercles  on  the  posterior  surface  of  the 
sacrum,  the  side  of  the  coccyx,  and  from  the  great  sciatic 
ligaments,  which  last  it  covers  :  the  fibres  are  collected  into 
distinct  fasciculi,  which  descend  obliquely  outwards  and 
forwards,  nearly  parallel  to  each  other,  converging  a  little 
towards  the  thigh ;  the  lower  fibres  are  the  longest,  they 
all  form  a  strong  and  dense  mass,  particularly  below,  and 
end  in  a  flat  and  thick  tendon,  whose  external  surface  is 
rough  and  coarse,  but  the  internal  smooth,  and  lined  by  a 
bursa  which  separates  it  from  and  allows  it  to  glide  over 
the  great  trochanter,  this  tendon  is  inserted  into  a  rough 
ridge  which  leads  from  the  trochanter  to  the  linea  aspera, 
also  into  the  upper  third  of  that  line,  and  by  a  tendinous 
expansion  into  the  fascia  lata,  covering  the  vastus  externus 
muscle.  Use,  to  extend  the  thigh,  also  to  abduct  and  rotate 
it  outwards,  to  support  and  extend  the  pelvis  and  the  trunk 
on  the  lower  extremity,  also  to  make  tense  the  fascia  lum- 
borum  and  the  fascia  lata.  The  glutseus  maximus  is  co- 
vered by  the  integuments,  by  a  considerable  depth  of  fat, 
and  by  a  thin  fascia ;  as  the  latter  approaches  the  upper 
edge  of  the  muscle,  it  becomes  more  strong  and  adherent, 
and  is  thence  extended  over  the  anterior  part  of  the  glutseus 
medius,  to  which  it  adheres  very  closely,  and  is  then  in- 
serted into  the  crest  and  anterior  spine  of  the  ilium.  The 
glutseus  maximus  covers  the  tuber  ischii  and  all  the  mus- 
cles on  the  posterior  part  of  the  pelvis,  except  the  anterior 
portion  of  the  glutseus  medius,  which  is  covered  by  the 


DUBLIN    DISSECTOR.  255 

fascia  just  now  mentioned  ;  its  insertion  into  the  linea  as- 
pera  is  above  the  short  head  of  the  biceps,  and  between 
the  vastus  externus  and  adductor  magnus ;  a  very  large 
bursa  lines  its  tendon,  and  is  expanded  over  the  trochanter 
and  a  portion  of  the  vastus  externus;  it  is  very  thin,  it 
usually  contains  much  synovial  fluid,  and  it  is  frequently 
intersected  by  tendinous  bands ;  a  smaller  bursa  is  often 
situated  below  it,  between  the  tendons  of  the  glutseus  maxi- 
mus  and  vastus  externus. 

Divide  this  muscle  by  a  perpendicular  incision,  and  se- 
parate the  edges ;  several  muscles,  vessels,  &c.  may  be  no- 
ticed, having  the  following  relation  to  each  other ;  com- 
mencing above,  we  see  the  glutseus  medius  muscle,  beneath 
this,  the  pyriformis,  and  between  these,  the  glutceal  vessels 
and  the  superior  glutseal  nerve ;  below  the  pyriform  mus- 
cle we  remark  the  great  sciatic  and  some  smaller  nerves, 
also  the  sciatic  and  pudic  vessels,  all  escaping  from  the 
pelvis  by  the  lower  part  of  the  sciatic  notch ;  next  in  order 
are  thegemclli  muscles  surrounding  the  tendon  of  the  obtu- 
rator internus,  below  these  is  the  quadratus  femoris,  paral- 
lel to  the  superior  fibres  of  the  abductor  magnus ;  the 
great  sciatic  ligament,  the  tuber  ischii,  and  the  superior 
attachment  of  the  hamstring  muscles  are  seen  in  this  dissec- 
tion, also  several  small  arteries  and  veins,  and  a  considera- 
ble quantity  of  loose  watery  cellular  tissue,  which  sur- 
rounds the  sciatic  nerve  in  its  course,  through  the  depres- 
sion between  the  trochanter  and  tuber  ischii. 

2.  GLUT^EUS  MEDIUS,  triangular,  flat,  thinner  than  the  last 
described  muscle,  is  exposed  by  dividing  the  glutseus  maxi- 
mus  and  dissecting  off  the  strong  fascia  which  extends  from 
its  anterior  edge  to  the  crest  of  the  ilium,  arises  by  fleshy 
and  aponeurotic  fibres  from  the  deep  surface  of  this  fascia, 
from  the  three  anterior  fourths  of  the  outer  edge  of  the  crest 
of  the  ilium,  from  the  superior  semicircular  line  or  ridge 
which  leads  from  the  anterior  spinous  process  of  the  ilium 
to  the  upper  part  of  the  sciatic  notch,  and  from  the  surface 
of  the  ilium,  above  and  below  that  ridge  ;  the  fibres  descend 
in  different  directions,  the  middle  perpendicularly,  the  an- 
terior, which  are  very  short,  and  the  posterior,  which  are 
long,  obliquely  ;  they  all  converge  into  a  strong  and  broad 
tendon,  which  is  inserted  into  the  upper  and  outer  part  of 
the  great  trochanter,  and  is  attached  anteriorly  to  the  ten- 
don of  the  glutseus  minimus.  Use,  to  abduct  the  thigh ;  its 
posterior  fibres  can  extend  and  rotate  it  outwards,  its  ante- 
rior fibres  can  flex  and  rotate  it  inwards  ;  it  also  serves  to 
maintain  the  pelvis  in  equilibrio  on  the  femur,  as  when 
standing  on  one  leg.  This  muscle  is  covered  in  part  by 
the  glutseus  maximus ;  the  anterior  and  larger  portion  is 


256  DUBLIN    DISSECTOR. 

covered  only  by  the  integuments  and  fascia  lata ;  it  lies  on 
the  glutseus  minimus,  its  posterior  edge  is  parallel  to  the 
pyriform  muscle,  and  separated  from  it  by  the  glutaeal  ves- 
sels and  nerves ;  the  anterior  edge  is  nearly  parallel  to  and 
behind  the  tensor  vaginse  muscle,  is  united  to  it  above,  but 
separated  from  it  below  by  a  quantity  of  fat,  and  by  seve- 
ral branches  of  the  external  circumflex  vessels  and  nerves. 

3.  GLUT^EUS  MINIMUS,  is  exposed  by  detaching  from  its 
origin  the  glutseus  medius  ;  small,  semicircular,  more  ten- 
dinous than  the  last,  it  arises  from  the  inferior  semicircular 
ridge  on  the  dorsum  of  the  ilium,  and  from  the  rough  sur- 
face between  it  and  the  edge  of  the  acetabulum  ;  the  fibres 
converge  as  they  descend,  and  end  in  a  strong  round  twist- 
ed tendon,  which  is  inserted  into  the   upper  and  anterior 
part  of  the  great  trochanter,  first  passing  over  a  small  bur- 
sa.     Use,  similar  to  the  last,  it  also  strengthens  the  ilio-fe- 
moral  articulation,  and  as  it  adheres  to  the  capsular  liga- 
ment, it  can  draw  this  out  of  the  joint  in  abduction  of  the 
thigh.    This  muscle  is  covered  by  the  glutseus  medius,  and 
a  little  overlapped  by  the  tendon  of  the  pyriformis,  it  covers 
the  capsular  ligament  and  the  external  tendon  of  the  rectus. 

4.  PYRIFORMIS,  is  of  a  flattened  triangular  form,  the  base 
at  the  sacrum  within  the  pelvis,  the  apex  at  the  trochanter ; 
situated  partly  within  the  pelvis,  partly  behind  the   hip 
joint,  nearly  parallel  to  the  posterior  border  of  the  glutasus 
minimus ;  it  arises  within  the  pelvis  by  three  tendinous  and 
fleshy  fasciculi,  from  the  anterior  or  concave  surface  of  the 
second,  third,  and  fourth  divisions  of  the  sacrum ;  it  also 
receives  a  few  fibres  from  the  anterior  surface  of  the  great 
sciatic  ligament,  and  from  the  upper  and  back  part  of  the 
ilium ;  the  fibres  form  a  thick  fleshy  belly,  which  passing 
through  the  great  sciatic  notch,  descends  obliquely  out- 
wards and  a  little  forwards,  and  is  inserted  by  a  round  ten- 
don into  the  upper  part  of  the  digital  fossa,  at  the  root  of 
the  great  trochanter  above  the  tendons  of  the  gemelli,and 
obturator  muscles,  to  which  it  is  connected.     Use,  to  abduct 
the  thigh,  to  extend  and  rotate  it  outwards,  it  can  also  act 
on  the  capsular  ligament  in  the  same  manner  as  the  glu- 
tseus minimus.    Within  the  pelvis  this  muscle  lies  on  the 
sacrum  and  is  covered  by  the  hypogastric  vessels,  the  scia- 
tic plexus  of  nerves,  and  the  rectum  ;  the  sciatic  nerve  of- 
ten perforates  it,  near  its  lower  margin  ;  on  the  dorsum  of 
the  pelvis  this  muscle  is  covered  by  the  glutseus  maximus, 
and  is  parallel  to,  but  not  covered  by  the  glutseus  medius  ; 
it  adheres  to  the  rnpsular  ligament,  and  is  superior  to  the 
gemelli,from  which  it  is  separated  by  the  sciatic  nerve  and 
vessels  ;  this  muscle  divides  the  sciatic  notch  into  two  parts, 
through  the  superior  pass  the  glutseal  vessels  and  nerves, 


DUBLIN    DISSECTOR.  257 

through  the  inferior  the  sciatic  and  pudic  vessels,  the  scia- 
tic nerve  and  several  smaller  branches  of  the  sacral  plexus 
of  nerves.  To  expose  the  following  five  small  rotator  mus- 
cles of  the  hip  joint,  draw  to  either  side  the  great  sciatic 
nerve,  and  remove  the  surrounding  loose  cellular  tissue. 

[Variety.  This  muscle  is  sometimes  divided  by  the  great  sciatic 
nerve  as  it  passes  out  of  the  pelvis.  So  far  as  I  have  observed,  this 
occurs  most  commonly,  when  there  is  also  an  anomaly  of  the  nerve 
itself,  which  consists  in  its  high  bifurcation,  one  trunk  coming  out 
in  the  usual  situation,  beneath  the  pyriform  muscle,  and  the  other, 
perforating  the  muscle.] 

5,  6,  GEMELLI,  two  small  muscles  behind  the  ilio-femoral 
articulation  between  the  ischium  and  the  trochanter,  the 
SUPERIOR  arises  narrow  and  fleshy  from  the  spine  of  the 
ischium :  the  fibres  pass  outwards  above  the  tendon  of  the 
obturator  internus,  and  are  inserted  with  it  into  the  upper 
part  of  the  digital  fossa  of  the  great  trochanter.  INFERIOR 
arises  also  fleshy,  from  the  upper  part  of  the  tuber  ischii, 
and  from  the  great  sciatic  ligament,  the  fibres  run  parallel 
to  the  former,  and  are  also  inserted  into  the  digital  fossa. 
Use,  to  rotate  the  thigh  outwards,  also  to  abduct  it,  to 
strengthen  the  capsular  ligament  and  to  confine  the  obtu- 
rator tendon  in  its  situation.  These  muscles  are  concealed 
by  the  ghita3us  maximus  and  the  sciatic  nerve ;  they  are 
placed  between  the  pyriformis  and  the  quadratus  femoris 
muscles :  they  form  a  sort  of  sheath  around  the  tendon  of 
the  obturator  internus,  and  adhere  to  its  edges;  they  appear 
as  portions  of  this  muscle  added  to  it  as  it  escapes  from  the 
pelvis :  the  inferior  is  the  larger  of  the  two :  the  superior 
is  inserted  between  the  pyriformis  and  the  obturator  inter- 
ims, and  the  inferior  between  the  tendons  of  the  obturator 
internus  and  externus :  they  both  adhere  to  the  capsular 
ligament. 

[  Varieties.  These  muscles  are  both  wanting  in  some  subjects ; 
in  others  one  only,  the  superior,  is  wanting,  which  is  said  to  be  analo- 
gous with  the  ape.] 

7.  OBTURATOR  INTERNUS,  is  situated  partly  within  the  pel- 
vis and  partly  behind  the  ilio-femoral  articulation ;  some- 
what triangular,  the  base  within  the  pelvis,  the  apex  at  the 
great  trochanter,  arises  by  aponeurotic  and  fleshy  fibres 
within  the  pelvis  from  the  superior  or  pelvic  surface  of  the 
obturator  or  thyroid  ligament,  and  from  all  the  circumfe- 
rence of  the  foramen  of  that  name,  except  at  the  upper 
part  where  the  obturator  nerve  and  vessels  pass  through : 
beneath  these  a  ligamentous  arch  is  extended,  and  from 
this  some  fibres  of  this  muscle  proceed  ;  it  also  arises  from 
the  pubis  internally,  and  from  the  ischium  inferiorlv,  and 
22* 


258  DUBLIN    DISSECTOR. 

from  a  thin  but  strong  fascia  of  the  same  name,  which  co- 
vers this  muscle  and  separates  it  from  the  levator  ani  mus- 
cle ;  the  fibres  descend  obliquely  outwards  and  backwards, 
converging  towards  the  lesser  sciatic  notch,  which  is  be- 
tween the  spine  and  the  tuberosity  of  the  ischium ;  the 
fibres  here  end  in  a  flat  tendon,  which  turning  outwards, 
winds  round  the  cartilaginous  pully-like  surface  which  the 
ischium  here  presents ;  a  loose  bursa,  and  one,  in  general, 
containing  a  quantity  of  synovia,  is  here  interposed  be- 
tween this  tendon  and  the  bone ;  the  tendon  now  runs  out- 
wards on  the  dorsum  of  the  pelvis,  between  the  gemelli 
muscles,  and  is  inserted  into  the  digital  fossa  of  the  great 
trochanter.  Use,  to  abduct  and  rotate  the  thigh  outwards  ; 
it  may  also  act  on  the  capsular  ligament.  This  muscle 
within  the  .pelvis  is  covered  by  the  peritoneum,  the  pelvic 
fascia,  levator  ani  muscle,  and  by  a  strong  aponeurosis, 
termed  the  obturator  fascia,  which  serves  to  give  origin  to 
some  fibres  both  of  the  obturator  muscle  and  of  the  levator 
ani,  between  which  it  is  interposed  ;  the  obturator  fascia 
is  the  external  layer  of  the  pelvic  fascia ;  it  adheres  supe- 
riorly to  the  ilium  and  pu  bis,  and  is  inserted  interiorly  into 
the  great  sciatic  ligament,  into  the  tuberosity  and  ramus 
of  the  ischium,  also  into  the  ramus  of  the  pubis,  it  here  be- 
comes continuous  with  the  triangular  ligament  of  the 
urethra ;  this  fascia  is  closely  connected  to  the  obturator 
internus  muscle,  except  inferiorly  where  the  internal  pu- 
dic  nerve  and  vessels  intervene.  As  the  obturator  tendon 
is  passing  through  the  sciatic  notch,  its  deep  surface  is  di- 
vided into  four  or  five  distinct  tendons,  which  are  lined  by 
the  synovial  membrane,  and  connected  to  each  other  like 
so  many  plaits  or  folds ;  the  pudic  vessels  lie  external  to 
this  tendon  in  this  situation ;  the  continuation  of  the  tendon  to 
its  insertion  has  the  same  relations  as  the  gemelli  muscles. 
8.  QUADRATUS  FEMORIS,  arises  by  fleshy  and  aponeurotic 
fibres  from  the  external  surface  of  the  tuber  ischii,  anterior 
to  the  tendon  of  the  semi-membranosus,  the  fibres  pass 
transversely  outwards,  and  are  inserted  tendinous  and  fleshy 
into  the  inferior  and  posterior  part  of  the  great  trochanter, 
and  into  the  posterior  intertrochanteric  line.  Use,  to  ad- 
duct  and  rotate  the  thigh  outwards  :  this  muscle  is  covered 
by  the  glutseus  maximus  and  sciatic  nerve ;  its  origin  is 
also 'concealed  by  the  hamstring  muscles  ;  it  is  parallel  to 
and  between  the  gemelli  and  the  adductor  magnus  ;  its  low- 
er border  is  overlapped  by  the  latter  ;  it  covers  the  obturator 
extemus,  the  lesser  trochanter,  and  the  insertion  of  the  psoas 
and  iliacus.  Divide  this  muscle,  and  a  little  dissection  will 
expose  the  following,  particularly  if  the  gracilis,  adductor, 
and  pectina3us  muscles  have  been  previously  removed. 


DUBLIN    DISSECTOR.  259 

[Varieties.  This  muscle  is  sometimes  wanting.  Very  rarely  it 
is  found  to  consist  of  a  large  number  of  fasciculi,  it  is  more  prone 
than  many  muscles,  to  a  fatiy  transformation.] 

9.  OBTURATOR  EXTERNUS,  situated  at  the  superior,  pos- 
terior, and  internal  part  of  the  thigh,  somewhat  triangular 
or  pyramidal,  the  base  towards  the  pubis,  the  apex  at  the 
trochanter,  arises  fleshy  from  the  inferior  surface  of  the 
thyroid  or  obturator  ligament,  and  from  the  surrounding 
surface  of  the  pubis  and  ischiurn,  the  fibres  descend  ob- 
liquely outwards  and  backwards  behind  the  -neck  of  the 
femur,  in  a  sort  of  notch  or  groove  between  the  tuber  ischii 
and  the  edge  of  the  acetabulum;  here  they  end  in  a  strong 
tendon,  which  ascends  a  little  behind  the  neck  of  the  femur, 
then  runs  directly  outwards  along  the  inferior  gemellus, 
and  adhering  to  the  capsular  ligament,  is  inserted  into  the 
lower  part  of  the  digital  fossa.  Use,  to  adduct  the  thigh, 
and  to  rotate  it  outwards ;  it  also  supports  and  strengthens 
the  inferior  and  posterior  part  of  the  ilio-femoral  articula- 
tion, particularly  in  abduction  of  the  thighu  This  muscle 
is  placed  in  a  very  deep  situation,  being  covered,  anteriorly, 
by  the  adductor  brevis  and  pectinseus,  also  by  the  obtura- 
tor nerve  and  vessels,  internally  by  the  adductor  muscles, 
externally  by  the  joint,  .and  posteriorly  by  the  quadratus 
femoris  and  gluta3us  rnaximus. 

The  several  small  muscles  just  described,  in  addition  to 
their  individual  actions,  effect  the  common  purpose  of 
strengthening  the  ilio-femoral  articulation.  The  capsular 
ligament  of  this  joint  is  covered  anteriorly  by  the  rectus, 
psoas,  and  iliacus ;  internally  by  the  pectinseus  and  obtu- 
rator externus ;  externally  by  the  tendon  of  the  rectus,  the 
glutaeus  minimus  arid  .medius,  posteriorly  by  the  pyriform, 
gemelli,  obturator  tendons  quadratus  femoris,  and  glutseus 
maximus,  and  inferiorly  by  the  tendon  of  the  obturator  ex- 
ternus. Many  of  these  muscles,  like  the  small  capsular 
muscles  of  the  shoulder  joint,  guard  Against  dislocation  in 
the  different  motions  of  the  limb,  and  also  serve  to  protect 
the  capsular  ligament  by  drawing  it  out  of  the  angle  which 
is  formed  between  the  acetabulum  and  the  neck  of  the  fe- 
mur in  the  rotatory  motion  of  the  limb. 

In  dissecting  the  foregoing  muscles,  several  vessels  and 
nerves  must  have  been  remarked;  the  former  are  derived 
from  the  hypogastric  or  internal  iliac  vessels  ;  the  latter 
from  the  sacral  plexus  of  nerves ;  the  arteries  are  the  glu- 
taeal,  sciatic,  and  pudic.  The  glutaal artery  escapes  through 
the  upper  part  of  the  sciatic  notch,  above  the  pyriform 
muscle,  and  immediately  divides  into  several  branches; 
these  are  distributed  to  the  three  glutaei  muscles.  The 
sciatic  artery  passes  out  of  the  pelvis  through  the  lower  part 


260  DUBLIN    DISSECTOR. 

of  the  great  sciatic  notch,  below  the  pyriformis  ;  its  prin- 
cipal branches  descend  between  the  tuber  ischii  and  the 
great  trochanter,  and  are  lost  in  the  surrounding  muscles. 
The  pudic  artery  escapes  from  the  pelvis  along  with  the  last 
described  vessel;  it  soon,  however,  re-enters  the  cavity 
through  the  lesser  sciatic  notch,  and  pursues  its  course  for- 
wards and  inwards  towards  the  perinseum  and  pubis,  lying 
at  first  on  the  internal  surface  of  the  obturator  internus, 
and  afterwards  on  the  rami  of  the  ischium  and  pubis,  its 
branches  are  distributed  to  the  external  organs  of  genera- 
tion, and  to  the  muscles  in  the  perinseum.  (See  Anatomy 
of  the  Vascular  System.)  Each  of  these  arteries  have 
their  corresponding  veins,  which  take  a  similar  course,  and 
terminate  in  the  internal  iliac  vein.  The  nerves  which  are 
found  in  this  situation  are  the  superior  and  inferior  glutaeal, 
the  posterior  cutaneous,  the  pudic,  the  great  and  lesser  sci- 
atic ;  these  are  all  branches  of  the  sacral  plexus.  The  su- 
perior glutaal  nerve  accompanies  the  glutsoal  artery,  and  is 
distributed  principally  to  the  glutseus  medius  and  minimus 
muscles.  The  inferior  glut&al  nerve  escapes  below  the  py- 
riform  muscle,  and  is  distributed  principally  to  the  glu- 
toeus  maximus.  The  inferior  or  lesser  sciatic  nerve  accom- 
panies the  last  through  the  sciatic  notch,  descends  obliquely 
inwards  round  the  tuber  ischii,  and  is  distributed  to  the 
surrounding  muscles  and  integuments.  The  posterior  cuta- 
neous nerve  also  passes  through  the  lower  part  of  the  great 
sciatic  notch,  descends  beneath  the  glutosus  maximus,  and 
then  becoming  cutaneous,  divides  into  several  long  branch- 
es, which  may  be  traced  along  the  posterior  surface  of  the 
thigh,  even  to  the  leg,  where  in  general  they  will  be  found 
to  communicate  with  the  posterior  cutaneous  nerves  of  that 
region.  The  pudic  nerves  take  the  same  course  as  the  pudic 
artery,  and  terminate  in  corresponding  branches.  The 
great  sciatic  or  posterior  crural  nerve,  is  the  largest  nerve  in 
the  body ;  it  passes  out  of  the  pelvis  below,  but  often 
through  the  pyriform  muscle,  descends  behind  the  hip  joint 
in  the  fossa  between  the  trochanter  and  tuber  ischii,  cover- 
ed by  the  glutseus  maximus,  and  passing  over  the  gemelli, 
obturator,  and  quadratus  muscles ;  its  course  along  the  back 
of  the  thigh,  and  its  branches,  shall  be  considered  after  the 
dissection  of  the  following  muscles. 

DISSECTION     OF     THE     MUSCLES    ON     THE     BACK     PART     OF     THE 
THIGH. 

THE  fascia  in  this  situation  has  been  already  noticed ; 
the  muscles  are  only  three  in  number,  and  are  commonly 
called  hamstring  muscles ;  the  semi-tendinosus  and  semi- 


DUBLIN     DISSECTOR.  261 

membranosus  form  the  inner,  the  biceps  the  outer  ham- 
string. 

BICEPS  FLEXOR  CRURIS,  consists  of  a  long  and  short, 
head  ;  the  LONG  HEAD  arises  from  the  outer  and  back  part 
of  the  tuber  ischii  in  common  with  the  semi-tendinosus, 
this  descends  obliquely  outwards,  and  soon  ends  in  a  thick 
fleshy  belly ;  about  the  inferior  third  of  the  thigh  it  joins, 
at  an  acute  angle,  the  SHORT  HEAD,  which  arises  fleshy  from 
the  linea  aspera,  between  the  vastus  externus  and  the  ad- 
ductors, commencing  below  the  insertion  of  the  glutseus 
maximus,  and  continuing  to  within  two  inches  of  the  exter- 
nal condyle ;  here  the  muscle  ends  in  a  strong  tendon, 
which  descends  at  first  behind  the  knee,  then  turns  forwards 
and  outwards  towards  the  head  of  the  fibula,  into  which  it 
is  inserted ;  the  tendon  is  here  divided  in  general  by  the  ex- 
ternal lateral  ligament  into  two  fasciculi,  the  superficial  of 
which,  in  addition  to  its  attachment  to  the  head  of  the  fibula, 
is  also  inserted  into  the  fascia  of  the  leg ;  and  the  deep  fas- 
ciculus which  is  also  inserted  into  the  fibula,  sends  some 
fibres  to  the  head  of  the  tibia.  Use,  to  flex  the  knee-joint, 
also,  by  its  long  head,  to  extend  the  thigh  and  rotate  the 
whole  limb  outwards ;  the  long  head  can  also  fix  the  pelvis, 
and  prevent  it  and  the  trunk  from  bending  forwards  on  the 
head  of  the  femur.  The  superior  fifth  of  this  muscle  is 
concealed  by  the  glutseus  maximus,  the  remainder  is  co- 
vered by  the  integuments  and  fascia,  and  descends  between 
the  vastus  externus  and  semi-tendinosus,  forming  the  outer 
hamstring ;  the  long  head  passes  over  the  semi-membra- 
nosus,  the  sciatic  nerve,  and  the  triceps  muscles ;  it  also 
conceals  the  short  head  :  inferiorly  the  biceps  passes  over 
the  external  articular  vessels  and  the  external  head  of  the 
gastrocnemius  muscle,  and  forms  the  outer  hamstring. 

[  Varieties.  The  short  head  is  sometimes  wanting  which  is  analo- 
gous to  some  of  the  inferior  animals ;  sometimes  there  is  a  slender 
third  head  from  the  tuber  ischii,  or  the  long  head,  which  runs  down 
the  leg  into  the  tendo  achillis ;  this  is  analogous  to  other  mammalia.] 

2.  SEMI-TENDINOSUS,  large,  flat,  and  fleshy  above,  round 
and  tendinous  below,  arises  by  fleshy  fibres  from  the  tu- 
berosity  of  the  ischium  in  common  with  the  long  head  of 
the  biceps,  also  from  the  inner  or  anterior  edge  of  the  ten- 
don of  the  latter  for  about  three  inches ;  it  descends  ob- 
liquely inwards,  and  about  four  inches  above  the  knee  it 
ends  in  a  long  round  tendon,  which  passing  behind  the 
head  of  the  tibia,  is  then  reflected  forwards  between  the 
tendon  of  the  semi-membranosus  and  the  internal  head  of 
the  gastrocnemius,  and  is  inserted  into  the  anterior  angle  of 
the  tibia  below  its  tubercle,  inferior  and  posterior  to  the 


262  DUBLIN    DISSECTOR. 

tendons  of  the  gracilis  and  sartorius,  to  which  it  is  connect- 
ed :  from  the  convex  edge  of  the  tendon  an  aponeurosis  is 
given  off,  which  joins  the  fascia  of  the  leg.  Use,  to  flex  the 
knee  and  rotate  the  leg  inwards,  to  extend  the  thigh,  to  sup- 
port the  pelvis,  and  prevent  the  trunk  falling  forwards. 
This  muscle  is  covered  superiorly  by  the  glutasus  maximus ; 
the  rest  of  its  course  is  superficial,  a  transverse  line  usual- 
ly intersects  it  about  its  centre. 

[Variety.  This  muscle  is  sometimes  divided  into  three  parts,  by 
two  transverse  tendinous  lines.] 

3.  SEMI-MEMBRANOSUS,  beneath  the  semi-tendinosus,  flat 
and  aponeurotic  superiorly,  thick  and  fleshy  in  the  middle, 
round  and  tendinous  below ;  arises  by  a  flat  tendon  from 
the  upper  and  outer  part  of  the  tuber  ischii ;  this  descends 
obliquely  inwards,  ends  in  a  fleshy  belly,  which  retains  this 
muscular  structure  lower  down  than  either  of  the  former 
muscles,  a  little  above  the  knee  it  ends  in  a  round  tendon, 
which  passes  behind  the  internal  condyle,  and  divides  into 
three  processes,  one  of  which  passes  outwards,  another 
downwards,  and  a  third  forwards;  the  first  is  a  broad 
aponeurosis,  which  ascends  obliquely  outwards,  beneath 
the  heads  of  the  gastrocnemius  muscle  over  the  back  part 
of  the  knee-joint,  and  is  inserted  into  the  external  condyle 
of  the  femur  ;  this  aponeurosis  has  been  termed  the  poste- 
rior ligament  of  the  knee-joint,  or  the  ligament  of  Winslow ; 
the  second  is  a  strong  and  broad  fascia,  which  descends 
over  the  poplitseus  muscle,  and  is  inserted  into  the  posterior 
part  of  the  heads  of  the  tibia  and  fibula,  and  is  also  con- 
tinuous with  the  fascia  of  the  leg ;  the  third  process  ap- 
pears the  continuation  of  the  tendon,  it  turns  forwards  be- 
neath the  internal  lateral  ligament,  round  the  head  of  the 
tibia,  into  which  it  is  inserted.  Use,  to  extend  the  thigh  on 
the  pelvis,  and  to  support  the  latter  on  the  thigh,  to  flex  the 
knee  and  to  rotate  the  leg  inwards ;  it  also  strengthens  the 
back  part  of  the  knee,  and  can  draw  the  synovial  mem- 
brane out  of  the  angle  of  the  joint.  This  muscle,  at  its 
origin,  lies  external  to  the  other  hamstring  muscles;  it  is 
covered  at  first  by  the  semi-tendinosus,  biceps,  and  glutseus 
maximus,  inferioiiy  it  is  superficial ;  above,  is  passes  over 
the  quadratus  femoris  and  adductor  magnus  muscles ;  be- 
low it  overlaps  the  popliteal  vessels,  and  the  internal  head 
of  the  gastrocnemius,  from  which  last  it  is  separated  by  a 
bursa ;  the  sciatic  nerve  is  on  its  outer,  the  gracilis  on  its 
inner  side. 

[This  muscle  together  with  the  last  forms  the  inner  hamstring.] 
The  arteries  which  are  met  with  in  the  dissection  of  these 
muscles  are  branches  of  the  sciatic,  circumflex,  perforating, 


DUBLIN    DISSECTOR.  263 

and  articular,  the  numerous  ramifications  of  these  vessels 
are  distributed  to  the  hamstring  and  adductor  muscles,  and 
are  accompanied  by  their  corresponding  veins ;  the  prin- 
cipal nerve  in  this  situation  is  the  great  sciatic ;  from  the 
back  part  of  the  hip  joint  this  large  nerve  descends  along 
the  back  of  the  thigh  to  the  upper  part  of  the  popliteal 
space,  where  it  divides  into  the  peronseal  and  posterior 
tibial  nerves;  in  this  course  it  is  covered  at  first  by  the 
glutreus  maximus,  afterwards  by  the  biceps  and  semi-ten- 
dinosus,  and  inferiorly  by  the  integuments  and  fascia ;  hav- 
ing passed  over  the  quadratus  femoris  and  the  other  small 
muscles  at  the  back  of  the  hip  joint,  it  next  lies  on  the  ad- 
ductor magnus,  and  inferiorly  on  a  quantity  of  adipose  sub- 
stance. The  sciatic  nerve  gives  oif  several  cutaneous  and 
muscular  filaments,  in  addition  to  its  two  terminating 
branches,  the  peronseal  and  the  posterior  tibial ;  the  peron- 
(cal  nerve  takes  the  course  of  the  biceps  tendon  towards  the 
head  of  the  fibula,  where  it  divides  into  several  branches 
which  are  distributed  to  the  integuments  and  muscles  on 
the  outer  and  forepart  of  the  leg,  as  will  be  described  in 
the  dissection  of  that  region.  The  posterior  tibial  nerve  ac- 
companies the  popliteal  vessels  through  the  space  of  that 
name,  which  space  the  students  should  next  examine. 

The  popliteal  space  is  situated  behind  the  knee-joint,  ex- 
tending upwards  for  about  one-fourth  of  the  thigh,  and 
downwards  for  about  one-sixth  of  the  leg;  it  is  somewhat 
oval,  is  bounded  internally  by  the  inner  hamstring,  and  the 
internal  head  of  the  gastrocnemius ;  externally  by  the 
biceps,  external  head  of  the  gastrocnemius,  and  the  plan- 
taris;  it  is  covered  by  the  integuments  and  by  a  strong 
fascia,  which,  derived  from  the  fascia  lata,  is  strengthened 
by  adhering  to  the  condyles  of  the  femur,  and  to  the  ad- 
joining tendons  ;  this  fascia  serves  to  approximate  the  sides 
of  this  region,  and  thus  to  give  to  it  a  considerable  depth. 
The  popliteal  space  is  bounded  before  by  the  flat  surface 
of  the  femur,  by  the  back  part  of  the  joint  covered  by  the 
ligament  of  Winslow,  by  the  head  of  the  tibia,  and  by  the 
poplitasus  muscle ;  in  this  region  are  contained  the  termi- 
nating branches  of  the  sciatic  nerve,  the  popliteal  artery 
and  vein  with  their  branches ;  also  some  lymphatic  ganglia 
and  much  adipose  substance.  The  nerves  are  superficial 
and  external  to  the  vessels,  that  is,  nearer  to  the  biceps ; 
the  vessels  are  close  to  the  bone,  and  near  to  the  semi- 
membranosus  muscle,  the  vein  being  superficial  and  a  little 
to  the  outer  side  of  the  artery ;  two  or  three  lymphatic 
ganglia  are  connected  to  the  latter ;  and  a  quantity  of  fat, 
which  is  of  a  peculiar  soft  consistence,  intervenes  between 
the  nerve  and  vessels.  The  course  of  the  perona3al  nerve 


264  DUBLIN    DISSECTOR. 

has  been  already  noticed ;  the  posterior  tibial  nerve  descends 
nearly  vertically  between  the  hamstring  muscles  and  the 
heads  of  the  gastrocnemius,  and  then  runs  beneath  the  sol- 
seus,  and  over  the  poplitseus ;  above  it  lies  to  the  outer  side 
of,  and  at  some  distance  from,  the  artery,  but  below  it  is  in 
close  contact  with  it,  and  to  its  tibial  or  inner  side,  it  then 
accompanies  the  posterior  tibial  vessels  down  the  leg,  and 
along  the  inner  side  of  the  heel,  to  the  sole  of  the  foot,  in 
which  course  it  shall  be  examined  afterwards ;  in  the  ham 
this  nerve  sends  off  muscular  branches,  also  the  posterior 
or  external  saphenus  nerve,  which  accompanies  the  posterior 
saphena  vein  along  the  back  of  the  leg,  towards  the  outer 
ankle,  behind  which  it  passes  to  the  external  and  superior 
part  of  the  foot,  where  it  is  distributed ;  this  nerve  is  by 
some  called  "communicans  tibialis."  The  popliteal  artery 
descends  obliquely  outwards  through  this  space,  and  at  the 
lower  edge  of  the  poplitseus  muscle  divides  into  the  ante- 
rior and  posterior  tibial  arteries ;  in  this  course  it  sends  off 
many  muscular  and  five  articular  branches,  the  latter  sup- 
ply the  ends  of  the  bones,  and  the  sy  no  vial  membrane  of 
the  knee-joint.  The  popliteal  vein  accompanies  the  artery, 
lying  superficial  and  somewhat  external  to  it ;  it  receives 
branches  which  correspond  to  those  of  the  artery ;  and  it 
is  joined  inferiorly  by  the  lesser  or  posterior  saphena  vein. 
Next  proceed  to  the  dissection  of  the  leg. 


SECTION  III. 


DISSECTION    OF    THE    LEG. 

REMOVE  the  integuments  of  the  leg  and  foot;  on  the 
plantar  surface  of  the  latter  they  are  always  remarkably 
hard  and  thick,  even  in  the  foetus,  particularly  beneath  the 
heel  and  the  first  and  last  joints  of  the  toes ;  in  these  situ- 
ations also  the  subcutaneous  fat  has  a  peculiar  granulated 
structure,  being  intersected  by  tendinous  bands,  which 
pass  from  the  skin  to  the  plantar  fascia.  Beneath  the  in- 
teguments of  the  leg  we  find  two  cutaneous  veins,  the  in- 
ternal and  external  saphena ;  the  internal  saphena  is  large 
and  regular,  and  has  numerous  branches ;  it  commences 
by  small  veins  from  the  upper  surface  of  the  toes,  and 
from  the  dorsum  of  the  foot ;  these  run  towards  the  inner 
malleolus  and  unite  in  one  large  vessel,  which  ascends 
along  the  inner  side  of  the  leg,  receiving  in  its  course  nu- 


DUBLIN    DISSECTOR.  265 

merous  branches  from  the  integuments ;  it  then  passes  be- 
hind  the  inner  condyle  of  the  femur,  and  ascending  along 
the  inner  and  anterior  part  of  the  thigh,  it  terminates  in 
the  femoral  vein  about  an  inch  and  a.  half  below  Poupart's 
ligament ;  on  the  thigh  this  vein  is  accompanied  by  small 
nerves,  which  are  derived  from  the  lumbar  plexus  and 
from  the  anterior  crural ;  along  the  leg  the  saphenus  nerve, 
a  branch  of  the  anterior  crural,  is  attached  to  it,  and  winds 
round  it.  The  posterior  or  external  saphena  vein  commences 
behind  the  external  ankle  from  the  junction  of  several 
small  veins  from  the  integuments  of  the  heel  and  sole  of 
the  foot ;  it  ascends  along  the  surface  of  the  gastrocnemius 
muscle,  accompanied  by  the  communicans  tibialis  nerve ; 
at  the  ham  this  vein  in  general  joins  the  popliteal  vein,  but 
sometimes  it  here  turns  inwards  and  joins  the  internal  sa- 
phena vein,  with  which  it  always  communicates  in  its 
course  along  the  leg.  Several  cutaneous  nerves  are  dis- 
tributed to  the  leg,  namely,  the  internal  saphenus,  from 
the  posterior  tibial,  and  several  cutaneous  branches  from 
the  peronseal  and  anterior  tibial  nerves  perforate  the  fascia 
of  the  leg  on  its  outer  and  anterior  part,  and  are  distribu- 
ted to  the  integuments  of  the  leg  and  foot. 

The  fascia  of  the  leg  is  derived  partly  from  that  of  the 
thigh ;  it  also  receives  additional  fibres  from  the  tendons 
around  the  knee-joint,  namely,  the  rectus  and  vasti  ante- 
riorly ;  the  vastus  externus  and  biceps  externally  ;  the  sar- 
torius,  gracilis,  and  inner  hamstring  internally  ;  the  fascia 
adheres  to  the  head  of  the  tibia  and  fibula,  to  the  spine  of 
the  tibia,  near  its  whole  length,  to  the  annular  ligaments  of 
the  ankle  joint,  and  to  the  malleoli ;  it  can  scarcely  be 
said  to  exist  on  the  anterior  surface  of  the  tibia,  which  is 
only  covered  by  the  skin  and  periosteum.  The  fascia  of 
the  leg  is  stronger  superiorly  than  inferiorly ;  near  the 
ankle  it  again  increases  in  strength  from  its  connexion  to 
the  malleoli  and  to  the  annular  ligaments  ;  these  are  two 
in  number,  the  anterior  and  internal.  The  anterior  annular 
ligament  is  a  little  above  the  joint ;  it  is  somewhat  square, 
and  stronger  externally  than  internally ;  in  the  latter  situ- 
ation it  is  attached  to  the  malleolar  process  of  the  tibia, 
and  to  the  os  naviculare ;  in  the  former  to  the  external 
malleolus,  and  to  the  upper  part  of  the  os  calcis ;  it  con- 
sists of  two  layers,  which,  by  separating  and  re-uniting, 
from  three  rings  or  sheaths  for  the  tibialis  anticus,  and  the 
two  extensor  tendons ;  the  anterior  tibial  vessels  and  nerves 
also  pass  beneath  it.  The  internal  annular  ligament  is  broad- 
er than  the  anterior ;  it  is  attached  to  the  internal  malleo- 
lus, and  to  the  os  catcis ;  it  forms  a  sort  of  arch  over  the 
groove  or  canal  in  which  the  three  flexor  tendons,  and  the 
2o 


266  DUBLIN    DISSECTOR. 

plantar  nerves  and  vessels  run.  The  fascia  of  the  leg  is 
thin  posteriorly ;  near  the  heel  it  is  indistinct :  on  either 
side  it  is  connected  to  the  sheaths  of  the  tendons  that  pass 
round  the  rnalleoli ;  and  on  each  side  of  the  tendo  Achillis 
it  sends  in  a  lamina  to  join  the  fascia  which  covers  the 
deep  muscles  of  the  leg.  The  fascia  serves  to  confine  the 
muscles  in  their  situation,  and  to  give  origin  to  many  of 
their  fibres  ;  this  last  effect  is  further  accomplished  by  inter- 
muscular  bands  or  septa,  which  pass  in  from  the  fascia, 
between  the  extensor  and  peronsei  muscles,  and  are  attach- 
ed to  the  tibia  and  fibula  and  interosseous  ligament.  From 
the  anterior  annular  ligament,  a  thin  fascia  is  extended 
over  the  dorsum  of  the  foot ;  that  covering  the  sole  of  the 
foot,  the  plantar  fascia,  is  remarkably  strong ;  it  arises  from 
the  extremity  of  the  os  calcis,  narrow  but  thick  and  strong ; 
it  passes  forwards,  expands  and  divides  into  three  parts, 
which  lie  on  different  planes,  and  which,  by  sending  in 
two  processes,  serve  to  separate  the  plantar  muscles  into 
three  orders,  the  internal,  middle,  and  external ;  the  lateral 
portions  of  this  fascia  are  attachad  to  the  sides  of  the  tar- 
sus and  metatarsus ;  the  internal  portion  is  the  weakest : 
the  middle  division  is  the  strongest,  and  on  a  plane  inferior 
to  the  internal ;  as  this  middle  portion  expands  beneath 
the  plantar  muscles,  it  is  strengthened  by  transverse  fibres, 
and  near  the  base  of  the  toes  it  divides  into  five  fasciculi, 
these  diverge,  and  opposite  the  head  of  each  metatarsal 
bone,  they  each  sub-divide  into  two  fasciculi ;  these  pass 
along  the  sides  of  the  metatarso-phalangeal  articulations, 
and  are  inserted  into  the  lateral  ligaments  of  these  joints, 
and  into  the  sheaths  of  the  flexor  tendons ;  between  these 
fasciculi  the  tendons  pass,  also  the  digital  vessels  and 
nerves  of  each  toe  :  the  plantar  fascia  possesses  the  same 
strength  as  ligamentous  structure ;  use,  it  serves  to  retain 
the  arched  form  of  the  foot,  and  to  protect  the  plantar  mus- 
cles, vessels,  and  nerves,  from  pressure ;  it  also  gives  at- 
tachment to  several  muscular  fibres.  The  muscles  of  the 
leg  may  be  divided  into  those  on  the  anterior,  external,  and 
posterior  part. 

DISSECTION    OF    THE  MUSCLES    ON    THE  ANTERIOR  AND  EXTERNAL 
PART    OF    THE   LEG. 

THE  muscles  on  the  forepart  of  the  leg  are  four  in  num- 
ber, viz.  the  tibialis  anticus,  extensor  pollicis,  extensor 
communis,  and  peronseus  tertius ;  the  muscles  on  the  outer 
side  of  the  leg  are  the  peronseus  longus  and  brevis ;  almost 
all  these  muscles  are  connected  to  each  other  superiorly, 
so  that  they  cannot  be  perfectly  separated  from  each  oth- 
er ;  they  all  adhere  to  and  partly  arise  from  the  fascia  of 


DUBLIN    DISSECTOR.  267 

the  leg,  therefore,  when  exposed,  they  present  a  rough  sur- 
face superiorly. 

1.  TIBIALIS  ANTICUS,  is  next  the  tibia,  somewhat  triangu- 
lar, large  and  fleshy  above,  tendinous  below,  arises  tendi- 
nous and  fleshy  from  the  outer  part  of  the  two  superior 
thirds  of  the  tibia,  from  the  head  of  the  fibula,  from  the 
inner  half  of  the  inter-osseous  ligament,  from  the  fascia  of 
the  leg,  and  from  the  intermuscular  septa  ;  the  fibres  des- 
cend obliquely  inwards,  end  in  a  strong  and  flat  tendon 
which  crosses  from  the  outer  to  the  forepart  of  the  tibia, 
runs  through  a  distinct  ring  in  the  annular  ligament,  near 
the  internal  malleolus,  passes  forwards  and  inwards  above 
the  astragalus  and  naviculare,  increases  in  breadth,  and  is 
inserted  into  the  inner  side  of  the  great  or  internal  cunei- 
form bone,  also,  by  a  tendinous  slip  into  the  base  of  the 
first  metatarsal  bone  or  that  of  the  great  toe.     Use,  to  flex 
the  ankle,  to  adduct  the  foot,  and  to  raise  its  inner  edge 
from  the  ground  ;  to  turn  the  toes  inwards,  also  to  support 
the  leg  when  standing,  and  prevent  it  bending  backwards. 
This  muscle  is  superficial  through  its  whole  length ;  the 
tendon,  at  its  insertion,  is  partly  concealed  by  the  abductor 
and  flexor  pollicis  brevis ;  superiorly  this  muscle  is  exter- 
nal to  the  tibia ;  inferiorly  it  is  anterior  to  it :  the  extensor 
communis,  and  extensor  pollicis,  the  anterior  tibial  vessels 
and  nerves  are  to  its  outer  or  fibular  side,  a  small  bursa 
separates  its  tendon  from  the  upper  part  of  the  internal 
cuneiform  bone ;  another  bursa  in  general  surrounds  it,  as 
it  is  passing  over  the  synovial  membrane  of  the  ankle 
joint. 

2.  EXTENSOR  DIGITORUM  LONGUS,   arises   tendinous   and 
fleshy  from  the  external  part  of  the  head  of  the  tibia,  from 
the  head  of  the  fibula,  and  from  about  three-fourths  of  this 
bone,  from  part  of  the  inter-osseous  ligament,  from  the  fas- 
cia of  the  leg,  and  its  intermuscular  septa ;  the  fibres  des- 
cend obliquely  inwards ;  a  liitle  below  the  middle  of  the 
leg  they  end  in  three  flat  tendons,  which  pass  under  the 
annular  ligament  through  a  ring  common  to  these  and  to 
the  peronseus  tertius,  and  extend  forwards  over  the  dorsum 
of  the  foot,  the  internal  of  the  three  tendons  here  divides 
into  two ;  the  four  tendons  now  extend  along  the  dorsum  of 
each  of  the  four  external  toes, — the  great  toe  does  not  re- 
ceive any, — and  are  inserted  into  the  last  phalanx  of  each. 
Use,  to  extend  the  toes  and  flex  the  ankle.    This  muscle 
is    superficial;    superiorly,   it  lies    between  the    tibialis 
anticus  and  peronseus  longus,  and  is  connected  to  both; 
in  the  middle  of  the  leg  it  is  between  the  extensor  pollicis 
and  perona?us  brevis  :  along  each  of  the  toes  these  tendons 
sub-divide  at  the  joints  between  the  first  and  second  pha- 


268  DUBLIN    DISSECTOR. 

langes,  into  fasciculi,  which  pass  over  the  sides  of  these 
articulations  as  the  extensor  tendons  do  on  the  fingers ;  on 
the  dorsum  of  the  toes  also  they  form  a  sort  of  aponeuro- 
sis  as  on  the  fingers,  the  tendons  of  the  lumbricales  and 
inter-ossei  as  also  the  tendons  of  the  extensor  brevis  assist 
ing  in  its  formation. 

3.  EXTENSOR  POLLICIS   PROPRIUS,    arises   tendinous   and 
fleshy  from  the  inner  edge  of  the  middle  third  of  the  fibula, 
and  from  the  inter-osseous  ligament  nearly  as  low  down  as 
the  ankle ;  a  few  fibres  also  proceed  from  the  lower  part 
of  the  tibia ;  the  fibres  descend  obliquely  forwards  to  a 
tendon,  which  passes  beneath  the  annular  ligament,  then 
runs  forwards  over  the  astragalus,  naviculare,  and  cunei- 
forme  internum ;  the  tendon  next  passes  over  the  first  me- 
tatarsal  bone,  and  is  inserted  by  two  tendinous  fasciculi,  one 
into  the  base  of  the  first  phalanx,  and  the  other  into  the 
base  of  the  second  or  last  phalanx  of  the  great  toe.     Use, 
to  extend  the  great  toe  and  flex  the  ankle  ;  it  may  also  ad- 
duct  the  foot,  and  rotate  it  inwards.  The  upper  and  middle 
portions  of  this  muscle  are  overlapped  and  concealed  by 
the  tibialis  anticus  and  extensor  cornmunis,  between  which 
muscles  it  is  situated ;  its  tendon  is  superficial ;  the  ante- 
rior tibial  nerve  and  vessels  separate  it  from  the  tibialis 
anticus  above,  and  from  the  extensor  communis  below ;  it 
lies  on  the  fibula  and  inter-osseous  ligament  above :  infe- 
riorly  it  crosses  over  the  tibial  vessels,  the  synovial  mem- 
brane of  the  ankle  joint,  and  the  bones  of  the  tarsus. 

4.  PERON^EUS  TERTIUS,  or  anticus,  appears  to  be  a  portion 
of  the  extensor  communis,  and  in  some  cases  cannot  be 
separated  from  it;  it  arises  from  the  anterior  surface  of  the 
lower  half  of  the  fibula ;   the  fibres  pass   forwards  to   a 
tendon  which  descends  along  with  that  of  the  extensor 
communis  beneath  the  annular  ligament ;   it  then  passes 
forwards  and  outwards,  and  is  inserted  broad  and  thin  into 
the  base  of  the  fifth  metatarsal   bone,   and  it  frequently 
sends  a  band  of  fibres  to  join  the  fourth  tendon  of  the  ex- 
tensor eommunis.     Use,  to  extend  the  little  toe,  to  flex  the 
ankle,  to  abduct  the  foot  and  raise  its  outer  edge.    This 
muscle  is  sometimes  wanting,  an  additional  tendon  from 
the  extensor  communis  will  then  supply  its  place ;  it  is  su- 
perficial ;  on  the  foot  it  conceals  the  extensor  ibrevis,  which 
may  be  next  examined. 

EXTENSOR  DIGITORUM  BREVIS,  is  the  only  muscle  situated 
on  the  upper  surface  of  the  foot,  it  arises  tendinous  and 
fleshy  from  the  upper  and  anterior  part  of  the  os  calcis, 
anterior  to  the  groove  for  the  peronseus  longus,  also  from 
the  cuboid  bone,  the  astragalus,  and  the  annular  ligament ; 
it  forms  a  flat  fleshy  belly,  which  passes  forwards  aad  in- 


DUBLIN    DISSECTOR.  269 

wards,  ends  in  four  flat  tendons,  of  which  the  two  internal 
are  the  strongest ;  the  little  toe  does  not  receive  any ;  these 
tendons  are  inserted  thus:  the  first  or  most  internal,  into 
the  base  of  the  first  phalanx  of  the  great  toe ;  the  three 
other  tendons  join  the  outer  edge  of  the  corresponding 
tendons  of  the  extensor  digitorum  longus,  and  assist  in 
forming  the  aponeurosis  which  covers  the  dorsum  of  each 
toe.  Use,  to  extend  the  toes  and  rotate  the  anterior  part  of 
the  foot  outwards.  This  muscle  is  partly  concealed  by  the 
tendons  of  the  long  extensor  and  -peronseus  tertius  ;  it  pro- 
jects, however,  behind  and  between  them ;  the  tendons 
cross  the  metatarsal  bones  and  the  inter-ossei  muscles,  be- 
neath and  in  a  contrary  direction  to  the  -long  extensor  ten- 
dons. There  is  no  analogous  muscle  to  this  on  the  dorsum 
of  the  hand. 

[Varieties.  The  inner  part  is  sometimes  distinct  from  the  rest, 
and  sometimes  the  muscle  presents  four  distinct  bellies,  as  in  birds. 
A  tendon  is  sometimes  sent  to  the  little  toe.] 

The  muscles  on  the  outer  part  of  the  leg  are  the  two  pe- 
ronaBi. 

1.  PERONJEUS  LONGUS,  arises  tendinous  and  fleshy  around 
the  head  of  the  fibula  and  from  the  adjacent  surface  of  the 
tibia,  from  the  upper  half  of  the  external  angle  of  the 
fibula,  from  the  fascia  and  inter-muscular  septa,  the  fibres 
descend    obliquely   backwards    and   outwards,   end   in  a 
strong,  flat  tendon,  which  passes  behind  the  external  mal- 
leolus,  through  a  groove  in  the  lower  end  of  the  fibula,  in 
which  it  is  bound  down  by  a  strong  aponeurosis,  lined  by 
a  synovia!  membrane  ;  it  then  passes  forwards,  downwards, 
and  inwards,  through  a  similar  groove  in  the  os  calcis  and 
cuboid  •;  it  next  passes  across  the  sole  of  the  foot,  above  the 
plantar  muscles,  obliquely  inwards  and  forwards  towards 
the  metatarsal  bone  of  the  great  toe,  into  the  outer  side  of 
which,  and  of  the  adjacent  sesamoid  bone,  it  is  inserted; 
also,  into  the  internal  cuneiform,  and  into  the  base  of  the 
second  metatarsal  bone.     Use,  to  extend  the  ankle  joint, 
turn  the  foot  outwards,  and  raise  its  outer  edge,  also  to 
press  the  great  toe  against  the  ground  as  in  walking ;  in 
the  leg  this  muscle  is  superficial,  and  is  situated  between 
the  extensor  communis  anteriorly  and  the  solceus  and  flexor 
pollicis  posteriorly ;  in  the  sole  of  the  foot  it  is  above  all 
the  muscles  there,  and  cannot  be  seen  until  these  are 
removed. 

2.  PERONJEUS  BREVIS,  arises  fleshy  from  the  outer  and  back 
part  of  the  lower  half  of  the  fibula,  and  from  the  inter-mus- 
cular septa  ;  the  fibres  descend  obliquely,  end  in  a  tendon 
which  passes  behind  the  external  malleolua  in  the  same 

23* 


270  DU'BLIN    DISSECTOR, 

groove  as  the  peronseus  longus;  it  them  passes  forwards 
through  a  distinct  groove  in  the  ©s  calcis  above  the  pero- 
naeus  longus,  and  is  inserted  into  the  base  of  the  metatarsal 
bone  of  the  little  toe,  and  into  the  os  cuboides.  Use,  simi- 
lar to  the  last.  This  muscle  arises  between  the  extensor 
longus  and  peronseus  longus,  and  descends  between  the 
peronseus  tertius  and  the  flexor  pollicis  longus,  and  partly 
concealed  by  the  peronseus  longus;  it  continues  fleshy 
lower  down  than  it,  and  projects  on  either  side  of  its  ten- 
don ;  it  is  separated  from  the  peronceus  tertius  by  the  ex- 
ternal malleolus  ;  in  the  groove  in  the  latter  it  is  beneath 
the  long  peronceal  tendon,  that  is  nearer  to  the  bone,  but 
on  the  os  calcis  it  is  superior  to  it;  an  aponeur©sis  some- 
times unites  its  insertion  to  that  of  the  extensor  tendon  of 
the  little  toe, 

[Variety.       This  muscle  is  sometimes  double.] 

In  the  dissection  ©f  the  foregoing  muscles  we  meet  with 
the  anterior  tibial  vessels  and  their  branches;  also  the 
perongeal  nerve  and  its  divisions.  The  anterior  tibial  artery 
is  a  branch  of  the  popliteal ;  it  passes  forwards  between 
the  solceus  and  popMtasus,  perforates  the  inter-osse@us  space, 
surrounded  by  some  fibres  of  the  tibialis  posticus ;  it  then 
descends  obliquely  inwards  and  forwards  as  far  as  the  cleft 
between  the  first  and  second  metatarsal  bones ;  ira  its  course 
down  the  leg  it  is  placed  at  first  between  the  tibialis  anticus 
and  extensor  communis,  in  the  middle  of  the  leg  between 
the  former  and  the  extensor  pollicis,  and  inferierly  between 
the  tendon  of  the  latter  and  that  of  the  extensor 'communis  ; 
above  it  lies  on  the  inter-osseous  membrane,  below  it  passes 
over  the  tibia,  the  synovial  membrane  of  the  ankle  joint, 
the. astragalus,  navicular.,  and  cuneiform  bones,  aiad  beneath 
the  annular  ligament  and  the  internal  tendon  of  the  exten- 
sor digitorum  brevis  ;  in  the  leg  the  anterior  tibial  artery 
sends  off,  first,  the  recurrent  branch,  which  ascends  on  the 
outer  and  fore  part  of  the  head  of  the  tibia,  and  meets  the 
external  articular  arteries;  second,  in  its  course  along  the 
leg,  several  muscular  branches ;  third,  near  the  ankle,  the 
two  nanJiiealar  branches,  of  these,  the  external  is  the  larger, 
andinoscialates  with  a  small  artery  (the  anterior  peronseal) 
which  perforates  the  inter-osseous  ligament  about  two 
inches  above  the  ankle  joint ;  on  the  tarsus,  the  anterior 
tibia!  artery  sends  off  the  tarsal  and  metatarsal  branches, 
which  pass  obliquely  outwards,  arid  supply  the  inter-ossei 
muscles,  the  bones  and  joints  of  the  tarsus  and  metatarsus  ; 
between  the  two  first  metatarsal  bones  the  anterior  tibial 
divides  into  the  superior  and  inferior  branch  ;  the  former 
supplies  the  integuments  of  the  great  toe ;  the  latter  passes 


'DUBLIN    DISSECTOR.  271 

deep  towards  the  sole  of  the  foot,  and  fains  the  external 
plantar  artery ;  the  anterior  tibial  artery  is  accompanied 
by  two  veins,  which  end  in  the  popliteal  vein.  The  pero- 
rucal  nerve  winds  around  the  head  of  the  fibula,  perforates 
the  peronee-us  longus,  and  divides  into  several  branches; 
some  of  these  supply  the  perenseal  muscles,  others  the  in- 
teguments on  the  outer  and  fore  part  of  the  leg  and  -foot ; 
and  the  continuation  of  the  peronreal  nerve  passes  obliquely 
forwards  and  downwards,  and  accompanies  the  anterior 
tibial  artery,  lying  in  general  superficial,  and  to  its  fibular 
side. 

EUSSECTION    OF    THE    MUSCLES    ON    THE   BACK    ©F    THE    LEG. 

THESE  muscles  are  seven  in  number,  and  may  be  divided 
into  a  superficial  :and  a  deep  layer ;  the  former  consists  of 
three,  the  gastrocnemius,  solseus,  and  plantaris ;  the  latter 
of  four,  the  tibialis  posticus,  flexor  pollicis  longus,  flexor 
digitorum  communis,  and  popliteeus.  The  cutaneous  nerves 
and  veins,  and  the  fascia,  have  been  already  noticed. 

[Variety.  The  tendinous  connection  with  the  flexor  communis 
is  often  wanting.] 

1.  GASTROCNEMIUS,  large  and  thick,  tendinous  below, 
fleshy  and  aponeurotic  above,  and  divided  into  two  heads, 
both  of  which  are  somewhat  oval,  convex  behind,  flat  be- 
fore;  the  internal  longer  and  larger  than  the.  external; 
arises  from  the  upper  and  back  part  of  the  internal  condyle 
of  the  femur.,  and  fleshy  from  the  oblique  ridge  above  it ; 
the  external  head  arises  in  the  same  manner,  from  above 
the  external  condyle,  but  is  not  so  long  or  large ;  the  fibres 
of  each  descend  converging,  and  form  two  fleshy  bellies, 
which  unite  a  little  below  the  knee  in  a  middle  tendinous 
line ;  about  the  middle  of  the  leg  the  muscle  ends  in  a 
broad  and  flat  tendon,  which  gradually  unites  with  that  of 
the  solseus,  and  both  form  that  strong  tendon  which  is  com- 
monly called  the  tendo  AchilUs,  and  which  is  inserted,  into 
the  lower  and  back  part  of  the  os  calcis.  Use,  to  extend 
the  ankle  joint,  and  thus,  by  raising  the  heel  from  the 
ground,  to  throw  the  weight  of  the  whole  body  forwards 
on  the  toes  as  in  progression  ;  to  flex  the  knee  joint,  also  to 
secure  the  articulation  against  displacement,  by  preventing 
the  condyles  of  the  femur  slipping  'backwards  oft'  those  of 
the  tibia.  This  large  muscle  is  superficial,  a  small  portion 
of  its  internal  head  is  overlapped  by  the  semi-membranosus; 
its  deep  surface  is  more  aponeurotic  than  its  superficial ; 
the  lower  angle  of  the  popliteal  space  separates  its  two 
heads;  in  this  angle  the  popliteal  vessels,  the  posterior 
tibial  nerve,  and  the  plantaris  muscle  are  contained ;  a 


272  DUBLIN    DISSECTOR. 

foursa  is  placed  between  each  head  of  this  muscle  and  the 
condyle  of  the  femur,  which  it  covers ;  the  external  head 
conceals  the  tendon  of  the  poplitseus ;  the  internal  covers 
the  deep  processes  of  the  semi-membranosus  tendon  and 
an  intervening  bursa,  also  the  insertion  of  the  poplitasus ; 
the  gastrocnemius  covers  the  greater  part  of  the  solreus, 
therefore,  to  examine  the  latter,  detach  the  heads  of  the 
gastrocnemius  from  the  condyles,  and  separate  this  muscle 
from  the  solseus  to  within  two  or  three  inches  of  the  heel ; 
the  plantaris  muscle  is  now  also  exposed. 

[This  muscle  is  said  to  be  the  one  most  frequently  affected  with 
fatty  transformation.  I  have  a  specimen  in  which,  one  lateral  half 
of  the  muscle  was  entirely  changed,  while  the  other  half  appeared 
quite  natural.  The  soleus  also  is  often  affected  at  the  same  time.] 

2.  PLANTARIS,  arises  fleshy  from  the  back  part  of  the 
femur  above  the  external  condylc,  and  from  the  posterior 
ligament  of  the  -knee ;  it  is  connected  to  the  external  head 
of  the  gastrocnemius,  and  forms  a  small  pyramidal  fleshy 
belly,  which  descends  obliquely  inwards,  crosses  the  popli- 
teal vessels,  and  ends  in  a  flat  tendon  (the  longest  in  the 
body)   which   descends    between  the   gastrocnemius  and 
solseus ;  and  when  the  tendons  of  these  muscles  are  about 
to  unite,  that  of  the  plantaris  becomes  superficial,  it  then 
descends  along  the  inner  side  of  the  tendo  Achillis  to  the 
heel,  and  is  inserted  into  the  posterior  part  of  the  os  calcis, 
a  little  anterior  to  the  tendo  Achillis :  it  has  also  some  con- 
nexion to  the  plantar  fascia.     Z7se,  to  extend  the  foot,  and 
turn  it  inwards,  also  to  make  tense  the  fascia,  and  to  flex 
the  knee;  its  origin  is  partly  concealed  by  the  external 
head  of  the  gastrocnemius  ;  its  tendon  also  is  at  first  covered 
by  this  muscle,  but  inferiorly  it  is  superficial.     This  mus- 
:cle  is  sometimes  wanting. 

3.  SOLJEUS,  of  an  oval  flattened  figure,  consists  superiorly 
of  two  heads,  which  are  not  so  distinct  from  each  other  as 
those  of  the  gastrocnemius;   the  external  is  longer  and 
larger  than  the  internal,  and  arises  from  the  back  part  of 
the  head  and  from  the  superior  third  of  the  fibula,  behind 
the  peronasus  longus :  the  internal  head  arises  from  the 
middle  third  of  the  tibia,  commencing  below  the  oblique 
insertion  of  the  poplitasus ;  the  two  heads  are  connected 
by  a  strong  tendinous  arch,  beneath  which  pass  the  poste- 
rior tibial  nerve  and  vessels;  all  the  fibres  descend  and 
form  a  large  oval  belly,  which  continues  fleshy  lower 'than 
the  gastrocnemius;  a  tendon  is  formed  first  on  its  superfi- 
cial surface,  which  is  gradually  united  to  that  of  the  gas- 
trocnemius to  form  the  tendo  Achillis ;  this  strong  tendon 
is  broad  and  thin  above,  narrow  in  the  middle,  and  round 
and  thick  below,  it  is  composed  of  strong  vertical  fibres 


DUBLIN    DISSECTOR.  273 

which  descend  behind  the  os  calcis,  over  a  bursa,  covering 
a  cartilaginous  impression  on  that  bone,  and  it  is  inserted 
into  a  rough  surface  below  that.  Use,  to  assist  the  gastroc- 
nemius  in  extending  the  ankle ;  this  muscle  is  almost  en- 
tirely concealed  by  the  gastrocnemius ;  a  little  below  the 
middle  of  the  leg,  however,  it  projects  on  each  side  of  the 
tendon  of  the  latter,  and  forms  the  lower  calf  of  the  leg  ;  it 
covers  the  deep  seated  muscles,  vessels,  and  nerves. 

Detach  the  solaeus  from  its  origin,  and  the  strong  deep 
fascia  of  the  leg  is  exposed ;  this  fascia  is  partly  derived 
from  the  semi-membranosus  and  poplitseus,  and  partly  from 
the  more  superficial  fascia  of  the  leg ;  it  adheres  to  the  ti- 
bia and  fibula,  to  the  solseus,  and  to  the  deep  muscles  ;  in- 
feriorly  this  fascia  is  strong,  and  is  connected  to  the 
sheaths  of  the  tendons  that  pass  behind  the  rnalleoli,  and  to 
the  internal  annular  ligament  of  the  ankle  ;  dissect  off  this 
fascia  and  clean  the  four  following  muscles. 

4.  PGPLITJTUS,  situated  obliquely  at  the  upper  and  back 
part  of  the  leg,  behind  the  knee,  and  above  the  other  mus- 
cles in  this  region,  flat  and  triangular,  arises  by  a  round 
tendon  from  a  depression  on  the  external  surface  of  the 
outer  condyle,  below  the  origin  of  the  external  lateral  liga- 
ment, descends  obliquely  inwards  and  backwards,  above 
the  head  of  the  fibula,  and  along  the  external  semi-lunar 
cartilage,  to  which  it  is  connected  by  the  synovial  mem- 
brane of  the  knee,  and  by  a  few  tendinous  fibres  ;  becomes 
broad  and  fleshy,  and  is  inserted  into  a  flat  triangular  sur- 
face, which  occupies  the  superior  fifth  of  the  posterior  sur- 
face of  the  tibia.     Use,  to  bend  the  knee,  and  when  bent,  to 
twist  the  foot  and  toes  inwards;  it  may  also  assist  when 
the  limb  is  extended  in  rotating  the  knee  outwards  :  it  sup- 
ports the  external  semi-lunar  cartilage,  and  moves  it  slight- 
ly, so  as  to  adapt  its  situation  to  the  external  condyle  of 
the  femur,  in  the  rotatory  motions  of  the  joint ;  the  popli- 
tseus  is  covered  by  the  two  heads  of  the  gastrocnemius  and 
plantaris,  also  by  the  external  lateral  ligament,  the  popli- 
teal nerve  and  vessels  ;  it  is  superior  to  the  inner  head  of 
the  sola3us,  and  passes  over  the  tibio-fibular  articulation  and 
the  back  part  of  the  tibia ;  it  is  nearly  parallel  to  the  up- 
per part  of  the  plantaris ;  the  tendon  is  nearly  surrounded 
by  the  synovial  membrane  of  the  knee,  it  lies  however  ex- 
ternal to' the  cavity  of  the  joint. 

5.  FLEXOR  DIGITORUM  PERFORATES,  longus,  or  communis, 
broader  in  the  centre  than  at  either  end,  arises  fleshy  from 
the  posterior  flat  surface  of  the  tibia,  commencing  below 
the  poplitseus,  and  extending  to  within  two  or  three  inches 
of  the  ankle,  also  from  the  fascia  and  inter-muscular  sep- 
ta ;  the  fibres  descend  obliquely  inwards  to  a  tendon  which 


274  DUBLIN    DISSECTOR. 

passes  behind  the  internal  malleolus,  in  a  groove  in  the 
tibia  which  is  lubricated  by  a  bursa,  and  in  which  it  is 
confined  along  with  the  tendon  of  the  tibialis  posticus  by 
the  internal  annular  ligament,  separated,  however,  from 
that  tendon  by  a  ligamentous  septum ;  each  tendon  also 
has  a  distinct  synovial  sac :  this  tendon  then  turns  forwards 
and  a  little  outwards  into  the  sole  of  the  foot,  still  confined 
in  a  bony  groove,  first  in  the  astragalus,  and  then  in  the  os 
calcis ;  in  the  sole  of  the  foot  it  lies  beneath  the  tendon  of 
the  flexor  pollicis,  and  is  connected  to  it  by  a  tendinous 
slip;  about  the  centre  of  this  region  it  expands  arid  re- 
ceives the  insertion  of  the  accessory  muscle,  it  then  divides 
into  four  tendons,  which  pass  to  the  four  outer  toes,  and 
opposite  the  first  phalanx,  each  tendon  enters  a  strong 
fibrous  sheath  which  is  lined  by  synovial  membrane  ;  this 
sheath  continues  as  far  as  the  extremity  of  the  second  pha- 
lanx, and  contains  also  the  corresponding  tendon  of  the 
flexor  digitorum  brevis;  opposite  the  base  of  the  second 
phalanx,  each  of  the  last  named  tendons  is  slit  for  the  trans- 
mission of  the  long  flexor  tendon,  which  continues  to  run 
forwards  to  be  inserted  into  the  last  phalanx  of  each  of  the 
four  lesser  toes.  Use,  to  flex  the  toes  and  the  metatarsus, 
to  extend  the  ankle,  and  to  steady  the  leg  on  the  foot  as 
when  standing.  This  muscle  in  the  leg  is  covered  by  the 
superficial  muscles,  the  deep  fascia,  and  the  tibial  vessels ; 
it  overlaps  the  tibialis  posticus,  and  is  on  the  inner  or  tibial 
side  of  the  flexor  pollicis ;  a  little  above  the  inner  ankle, 
the  tendon  of  the  tibialis  posticus  crosses  above  that  of  the 
flexor  communis,  that  is,  becomes  nearer  to  the  tibia ;  in 
the  sole  of  the  foot  its  direction  is  horizontal,  it  is  there  su- 
perior to  the  flexor  brevis,  inferior  to  the  transversalis  pe- 
dis  and  peronseus  longus  tendon ;  the  lumbricales  muscles 
arise  from  its  tendons. 

6.  TIBIALIS  POSTICUS,  larger  above  than  below,  arises  from 
the  posterior  and  internal  part  of  the  fibula,  from  the  up- 
per part  of  the  tibia  and  from  almost  the  entire  length  of 
the  inter-osseous  ligament ;  the  fibres  descend  and  end  in 
a  strong  tendon  which  passes  along  with  that  of  the  last 
muscle  behind  the  internal  ankle,  crosses  above  that  ten- 
don and  then  proceeds  obliquely  forwards  and  inwards, 
and  is  inserted  into  a  tuberosity  on  the  inferior  and  internal 
part  of  the  os  naviculare  and  into  the  internal  cuneiform 
bone ;  it  also  sends  some  fibres  to  the  cuboid  and  to  the 
second  and  third  metatarsal  bones ;  a  small  bony  or  carti- 
laginous tubercle  is  often  found  in  this  tendon,  near  to  its 
insertion,  beneath  the  head  of  the  astragalus;  it  also  glides 
over  a  small  bursa  in  this  situation.  Use,  to  extend  the  an- 
kle and  10  raise  the  inner  edge  of  the  foot  from  the  ground ; 


DUBLIN    DISSECTOR.  275 

the  upper  end  of  this  muscle  is  notched  by  the  anterior  ti- 
bial  vessels,  a  few  of  its  fibres  accompany  these  vessels 
through  the  inter-osseous  space  and  are  attached  to  the  an- 
terior surface  of  the  ligament ;  in  its  course  down  the  leg 
it  is  covered  by  the  soteus  and  overlapped  by  the  flexor 
communis  and  flexor  pollicis,  it  covers  the  tibia,  fibula  and 
inter-osseous  ligament ;  it  passes  beneath  the  head  of  the 
astragalus  and  supports  that  strong  fibro-cartilage,  which 
extends  from  the  os  calcis  to  the  os  naviculare,  beneath 
the  head  of  the  astragalus,  which  substance  supports  a 
great  portion  of  the  weight  of  the  body  in  standing  or  in 
progression. 

7.  FLEXOR  POLLICIS  LONGUS,  arises  from  the  two  inferior 
thirds  of  the  fibula  by  fleshy  fibres  which  descend  oblique- 
ly inwards  to  a  tendon  which  passes  behind  the  internal 
malleolus  through  a  groove  first  in  the  tibia  and  next  in 
the  astragalus ;  entering  the  sole  of  the  foot  this  tendon 
crosses  above  the  flexor  communis  and  is  connected  to  it 
by  a  tendinous  slip,  it  then  proceeds  forwards  and  inwards, 
between  the  two  portions  of  the  flexor  pollicis  brevis,  en- 
ters a  tendinous  sheath,  and  is  inserted  into  the  last  phalanx 
of  the  great  toe.  Use,  to  flex  this  toe,  to  extend  the  ankle 
and  adduct  the  foot ;  this  muscle  lies  to  the  fibular  side  of 
the  tibialis  posticus,  between  it  and  the  peroneei  muscles  ; 
as  it  passes  behind  the  internal  ankle  it  is  about  half  an 
inch, behind  the  tendons  of  the  tibialis  posticus  and  the 
flexor  communis,  and  is  separated  from  these  by  the  poste- 
rior tibial  nerve  and  vessels. 


SECTION  V. 


DISSECTION    OF    THE    MUSCLES    OF    THE    FOOT. 

THERE  is  but  one  muscle  on  the  dorsum  or  on  the  upper 
surface  of  the  foot,  the  extensor  digitorum  brevis,  which 
has  been  already  examined,  as  being  a  sort  of  appendix  to, 
or  continuation  of  the  long  extensors  of  the  toes  which 
arise  from  the  bones  of  the  leg.  The  integuments  and  fas- 
cia in  the  sole  of  the  foot  have  been  already  noticed  ;  the 
muscles  here  are  very  numerous,  they  may  be  divided  into 
four  lamina?,  these  are  tolerably  distinct  about  the  middle 
of  this  region,  but  at  either  side  this  arrangement  is  rather 
artificial ;  the  two  inter-muscular  processes  of  the  plantar 
fascia  also  divide  these  muscles  into  three  compartments, 
an  internal,  a  middle,  and  an  external.  The  muscles  of 


276  DUBLIN    DISSECTOR. 

the  first,  or  superficial  layer,  are  the  abductor  pollicis, 
flexor  digitorum  brevis,  and  abductor  minimi  digiti :  in  the 
second  layer  are  the  long  flexor  tendons,  the  accessory 
muscle,  and  the  lumbricales :  the  third  layer  consists  of  the 
flexor  pollicis  brevis,  adductor  pollicis,  transversalis  pedis, 
and  flexor  minimi  digiti ;  in  the  fourth  layer,  are  the  inter 
ossei  muscles,  and  the  tendon  of  the  peronseus  longus. 

ABDUCTOR  POLLICIS,  arises  tendinous  and  fleshy  from  the 
lower  and  inner  part  of  the  os  calcis,  from  the  internal  an- 
nular ligament,  the  plantar  aponeurosis,  and  internal  in- 
ter-muscular septum;  the  fibres  pass  forwards  and  in  wards, 
and  are  inserted  tendinous  into  the  internal  sesamoid  bone, 
and  into  the  internal  side  of  the  base  of  the  first  phalanx 
of  the  great  toe.  Use,  to  separate  the  great  toe  from  the 
others  ;  this  muscle  is  by  some  writers  called  the  adductor 
pollicis,  its  action  being  then  referred  to  the  mesial  line  of 
the  body ;  it  is  the  most  internal  of  the  plantar  muscles, 
and  is  superficial,  the  fascia  covering  it  is  very  thin. 

FLEXOR  DIGITORIUM  BREVIS  PERFORATUS,  arises  from  the 
inferior  and  rather  from  the  internal  part  of  the  os  calcis, 
from  the  internal  annular  ligament,  the  plantar  aponeuro 
sis,  and  inter-muscular  septa  ;  it  forms  a  fleshy  mass,  which 
passing  forwards  divides  about  the  middle  of  the  foot  into 
four  delicate  tendons,  which  accompany  the  flexor  longus 
communis  into  the  tendinous  and  synovial  sheaths,  beneath 
the  phalanges  of  the  four  outer  toes  ;  each  tendon  is,  slit 
opposite  the  base  of  the  second  phalanx,  and  having  trans- 
mitted the  long  flexor  tendon,  this  short  tendon  is  then  fold- 
ed out  on  the  inferior  surface  of  the  second  phalanx,  and 
is  inserted  into  it,  above  the  long  flexor  tendon.  Use,  to  as- 
sist the  long  flexor,  to  strengthen  the  plantar  fascia,  and  to 
preserve  the  arch  of  the  foot ;  this  muscle  is  immediately 
above  the  strong  central  portion  of  the  plantar  fascia,  from 
which  a  considerable  portion  of  it  arises,  therefore  it  always 
presents  a  rough  surface,  when  dissected  ;  it  is  beneath  the 
long  flexor  tendons,  the  accessory  muscle,  and  the  lumbri- 
cales ;  it  is  joined  to  the  abductor  pollicis  posteriorly,  but 
anteriorly  is  separated  from  it  by  the  tendon  of  the  flexor 
pollicis  longus :  the  fourth  or  the  external  of  its  tendons, 
or  that  for  the  little  toe,  is  sometimes  wanting. 

ABDUCTOR  MINIMI  DIGITI,  is  situated  along  the  outer  edge 
of  the  foot,  arises  tendinous  and  fleshy  from  the  outer  side 
of  the  os  calcis,  and  from  a  strong  ligament  which  ex- 
tends from  this  to  the  fifth  metatarsal  bone,  also  from  the 
base  of  the  latter,  from  the  plantar  fascia  and  its  external 
inter-muscular  septum ;  inserted  tendinous  into  the  outer 
side  of  the  base  of  the  first  phalanx  of  the  little  too,  and 
into  the  adjoining  surface  of  the  metatarsal  bone.  Use,  to 


DUBLIN    DISSECTOR.  277 

separate  the  little  toe  from  the  others,  .and  to  flex  it ;  this 
muscle  is  also  superficial,  the  fascia  covering  it  is  very 
strong,  it  is  the  most  external  of  the  muscles  in  this  region, 

Detach  this  first  layer  of  muscles  from  their  posterior 
attachments,  and  throw  them  forwards  towards  the  toes ; 
the  tendons  of  the  flexor  pollicis  and  communis  are  now 
exposed,  also  the  accessory  muscle  and  the  lumbricales  ; 
all  these  constitute  the  second  layer  of  the  plantar  muscles, 
which  is  partially  concealed  by  the  first. 

The  tendon  of  the  flexor  longus  digitorum  communis  is 
seen  passing  from  the  inner  side  of  the  os  calcis  to  the 
middle  of  the  plantar  region,  where  it  divides  into  its  four 
tendons,  which  have  been  already  described  as  entering  the 
sheaths  on  the  inferior  surface  of  the  four  outer  toes,  pass- 
ing through  the  slits  in  the  tendons  of  the  flexor  brevis, 
and  then  inserted  into  the  last  phalanx  of  each  toe.  The 
tendon  of  the  flexor  pollicis  longus  is  now  also  seen  pass- 
ing above  the  former,  to  which  it  is  united  by  a  tendinous 
fasciculus,  and  then  proceeding  forwards  to  its  insertion  in 
the  base  of  the  great  toe. 

MUSCULUS  ACCESSORIUS,  or  flexor  digitorum  accessorius, 
arises  fleshy  and  tendinous,  from  the  inferior  and  internal 
part  of  the  os  calcis,  forms  a  flat  and  somewhat  square 
fleshy  belly,  which  proceeding  forwards,  is  inserted  into  the 
upper  and  outer  part  of  the  tendon  of  the  flexor  digitorum 
longus,  just  before  it  divides.  Use,  to  assist  the  long  flexor, 
and  to  counteract  its  obliquity  by  pulling  it  directly  towards 
the  heel;  this  muscle  lies  above  the  flexor  digitorum  brevis. 
There  is  no  analogous  muscle  to  this  in  the  hand,  as  there 
the  flexor  tendons  pass  directly  over  the  centre  of  the 
carpus. 

LUMBRICALES  are  four  small  muscles  which  arise  tendi- 
nous and  fleshy  from  the  tendons  of  the  flexor  digitoruro 
longus ;  there  is  none  for  the  great  toe  ;  the  first  or  the  in- 
ternal one  is  the  largest ;  these  four  muscles  proceed  for- 
wards  along  the  internal  edge  of  the  long  flexor  tendons, 
each  ends  in  a  thin  aponeurosis,  which  is  inserted  into  the 
internal  side  of  the  first  phalanx  of  the  four  lesser  toes,  and 
joins  the  tendinous  expansion  of  the  extensor  tendons  on 
the  dorsum  of  the  toes.  Use,  to  adduct  and  to  assist  in  flex- 
ing the  four  toes,  they  may  also  extend  their  second  and 
last  phalanges.  These  muscles  are  covered  in  the  sole  ot 
the  foot  by  the  superficial  layer  ;  their  tendinous  insertions 
are  superficial,  and  are  best  seen  on  the  dorsum  of  the  toes. 
These  are  analogous  to  the  four  lumbricales  in  the  hand, 
where  they  arise  also  from  the  deep  or  perforating  flexors, 
and  run  along  the  radial  side  of  each  tendon,  or  that  next 
the  thumb,  so  in  the  foot  they  run  along  that  side  which 


278  DUBLIN    DISSECTOR. 

corresponds  to  the  great  toe ;  hence,  although  they  are  de- 
scribed as  running  along  the  outer  sides  of  the  flexor  ten- 
dons in  the  hand,  and  along  the  inner  in  the  foot,  yet  still 
they  are  perfectly  analogous,  supposing  the  hand  in  the 
prone  position,  or  the  foot  in  the  supine.  Detach  this  se- 
cond layer  of  muscles  and  throw  it  also  forwards  towards 
the  toes. 

The  third  layer  of  the  plantar  muscles  consists  of  the 
flexor  pollicis  brevis,  adductor  pollicis,  transversalis  pedis, 
and  flexor  minimi  digiti. 

FLEXOR  POLLICIS  BREVIS,  narrow  posteriorly,  broad  and 
notched  anteriorly ;  arises  by  a  strong  tendon  from  the 
lower  and  anterior  part  of  the  os  calcis,  also  from  the  ex- 
ternal cuneiform  bone,  it  forms  a  fleshy  belly  which  is  inse- 
parably connected  to  the  abductor  and  adductor  pollicis, 
and  passes  forwards  and  inwards,  and  divides  into  two 
short  tendons ;  these  are  inserted  into  the  sesamoid  bones 
beneath  the  first  phalanx  of  the  great  toe.  Use,  to  flex  the 
first  joint  of  the  great  toe,  also  to  approximate  this  toe  to 
the  others.  This  muscle  forms  a  sort  of  sheath  for  the  ten- 
don of  the  flexor  pollicis  longus,  and  is  analogous  to  the 
short  flexor  on  the  thumb. 

ADDUCTOR  POLLICIS,  is  situated  external  to  the  last  muscle, 
or  more  in  the  centre  of  the  foot ;  it  is  also  inseparably  at- 
tached to  it ;  it  arises  tendinous  and  fleshy  from  the  strong 
calcaneo-cuboid  ligament,  and  from  the  base  of  the  second 
and  third  metatarsal  bones,  it  passes  forwards  and  inwards, 
and  is  inserted  along  with  the  external  portion  of  the  last 
muscle  into  the  external  sesamoid  bone.  Use,  to  draw  the 
great  toe  outwards  towards  the  other  toes,  also  to  flex  it,  so 
as  to  bring  the  great  toe  beneath  the  other  toes.  By  some 
this  muscle  is  named  the  abductor  pollicis,  its  action  being 
then  referred  to  the  mesial  line. 

TRANSVERSALIS  PEDIS,  arises  by  distinct  fleshy  slips  from 
the  anterior  extremities  of  the  four  external  metatarsal 
bones ;  the  fibres  pass  inwards  and  forwards,  converging  to 
the  external  sesamoid  bone  of  the  great  toe,  into  which  they 
are  inserted  along  with  the  last  described  muscle.  Use,  to 
approximate  the  toes,  and  to  contract  the  transverse  arch 
of  the  foot ;  there  is  no  analogous  muscle  in  the  hand  ;  be- 
hind this  muscle,  and  nearly  parallel  to  it,  the  strong  cal- 
caneo-cuboid ligament  is  observed,  also  the  tendon  of  the 
tibialis  posticus  dividing  into  several  slips,  which  are  in- 
serted into  the  adjacent  bones  and  ligaments. 

FLEXOR  BREVIS  MIN.MI  DIGITI,  arises  tendinous  and  fleshy 
from  the  cuboid  and  fifth  metatarsal  bone,  and  from  the 
sheath  of  the  peroneeus  longus  tendon ;  it  passes  forwards 
and  outwards,  and  is  inserted  into  the  inner  side  of  the  base 


DUBLIN    DISSECTOR.  279 

of  the  first  phalanx  of  the  little  toe.  Use,  to  flex  and  ad- 
duct  this  toe.  This  muscle  is  connected  to  the  abductor 
minimi  digiti ;  it  fills  up  the  concavity  of  the  fifth  metatar- 
sal  bone.  Detach  these  four  muscles  in  this  layer  from  the 
tarsus,  and  the  fourth  layer  will  come  into  view,  namely, 
the  tendon  of  the  peronseus  longus  and  the  interossei  mus- 
cles ;  the  former  crosses  the  foot  obliquely  forwards  and 
inwards  from  a  deep  groove  in  the  cuboid,  beneath  the  cu- 
neiform and  metatarsal  bones,  to  be  inserted  into  the  inter- 
nal cuneiform,  and  into  the  base  of  the  first  and  second 
metatarsal  bones ;  in  this  course  this  strong  round  tendon 
is  enclosed  in  a  tendinous  sheath,  which  is  lined  by  syno- 
vial  membrane,  and  is  attached  to  the  several  projections 
of  the  adjoining  bones.  Use,  to  serve  as  a  strong  trans- 
verse ligament  in  strengthening  the  tarsus  and  metatarsus 
in  that  direction  ;  this  course  and  connexion  of  the  tendon 
explain  the  action  of  the  personseus  longus  muscle,  namely, 
to  extend  the  ankle  joint,  to  elevate  the  external  side  of  the 
foot,  to  depress  its  internal  side,  and  to  turn  the  point  of 
the  foot  outwards. 

INTEROSSEI  MUSCLES  are  seven  in  number;  three  are  seen 
in  the  sole  of  the  foot,  and  four  on  the  dorsum  ;  they  fill  up 
the  interstices  between  the  metatarsal  bones  :  the  three  in- 
ferior are  named  interossei  interni  or  inferiores ;  they  arise 
tendinous  and  fleshy  from  between  the  metatarsal  bones  of 
the  four  external  toes,  and  are  inserted  tendinous  into  the 
inner  side  of  the  base  of  the  first  phalanx  of  the  three  les- 
ser toes.  Use,  to  adduct  the  toes. 

The  first  of  the  inferior  interossei  is  situated  between  the 
second  and  third  metatarsal  bones,  it  arises  chiefly  from  the 
inner  side  of  the  latter,  and  is  inserted  into  the  inner  side  of 
the  first  phalanx  of  the  third  or  middle  toe ;  this  may  be 
named  the  adductor  medii  digiti ;  the  second  is  between  the 
third  and  fourth  metatarsal  bones ;  arises  chiefly  from  the 
inner  side  of  the  latter,  aud  is  inserted  into  the  inner  side  of 
the  first  phalanx  of  the  fourth  toe,  and  may  be  named  ad- 
ductor quarti  digiti ;  the  third  is  between  the  fourth  and  fifth 
metatarsal  bones,  arises  from  the  latter,  and  is  inserted  into 
the  inner  side  of  the  little  toe,  and  may  be  named  the  ad- 
ductor minimi  digiti. 

The  interossei  externi  or  superiores  are  four  in  number,  are 
larger  than  the  last,  and  are  seen  on  the  dorsum  or  convex 
surface  of  the  foot ;  they  are  bicipital  muscles ;  the  first  is 
between  the  first  and  second  metatarsal  bones,  and  may  be 
named  the  adductor  digiti  secundi ;  it  arises  from  the  internal 
side  of  the  second  metatarsal  bone,  and  by  a  distinct  fas- 
ciculus from  the  outer  side  of  the  first ;  these  two  origins 
are  separated  by  the  deep  branch  of  the  anterior  tibial  ar- 


280  DUBLIN    DISSECTOR. 

tery ;  the  fibres  end  in  a  tendon  which  is  inserted  on  the  in- 
ner side  of  the  base  of  the  first  phalanx  of  the  second  toe  ; 
it  also  joins  the  corresponding  extensor  tendon.  Use,  to  ap- 
proximate the  second  to  the  great  toe. 

ABDUCTOR  DIGITI  SECUNDI  is  placed  between  the  second 
and  third  metatarsal  bones ;  arises  from  their  opposite  sur- 
faces, but  chiefly  from  that  of  the  former ;  the  fibres  end  in 
a  tendon  which  is  inserted  into  the  outer  side  of  the  first 
phalanx  of  the  second  toe.  Use,  to  separate  the  second 
from  the  great  toe, 

ABDUCTOR  DIGITI  MEDII  is  placed  between  the  third  and 
fourth  metatarsal  bones,  and  arises  from  their  opposite  sur- 
faces, but  chiefly  from  that  of  the  third;  the  fibres  end  in 
a  tendon  which  is  inserted  into  the  outer  side  of  the  first 
phalanx  of  the  third  or  middle  toe.  Use,  to  separate  the 
third  toe  from  the  first  and  second. 

ABDUCTOR  DIGITI  QUARTI  is  situated  between  the  fourth 
and  fifth  metatarsal  bones ;  it  arises  from  their  opposite  sur- 
faces, and  is  inserted  into  the  outer  side  of  the  first  phalanx 
of  the  fourth  toe.  Use,  to  separate  the  fourth  toe  from  the 
three  internal. 

All  the  interossei  muscles  serve  to  strengthen  the  meta- 
tarsus, to  press  the  metatarsal  bones  together ;  they  also 
serve  to  flex  the  first  joint  of  the  four  outer  toes,  and  may 
assist  in  extending  their  last  phalanges ;  these  muscles  can 
exert  no  influence  on  the  great  toe  ;  there  is  only  one  mus- 
cle between  the  two  first  metatarsal  bones;  between  the 
others  there  are  two,  therefore  there  are  four  superior  or 
dorsal  interossei  muscles,  but  three  inferior ;  the  latter  are 
situated  more  in  the  concavity  of  each  metatarsal  bone  than 
between  these  bones ;  the  superior  are  stronger  and  more 
tendinous  than  the  inferior ;  and  are  only  partially  covered 
by  the  long  and  short  extensor  tendons. 

In  dissecting  the  muscles  on  the  back  of  the  leg,  and  those 
in  the  sole  of  the  foot,  we  meet  the  posterior  tibial  vessels 
and  nerve,  and  their  principal  branches.  The  posterior 
tibial  artery  is  the  larger  branch  of  the  popliteal ;  it  descends 
obliquely  inwards  beneath  the  deep  fascia  and  the  superfi- 
cial muscles,  and  over  the  tibialis  posticus  and  flexor  com- 
munis,  to  the  fossa  between  the  heel  and  inner  ankle,  it 
here  ends  in  the  two  plantar  arteries ;  in  this  course  it 
gives  off  many  muscular  branches,  also  the  peron&al  artery; 
the  latter  arises  from  the  tibial,  about  an  inch  below  the 
poplitseus ;  it  descends  obliquely  outwards  along  the  back 
part  of  the  fibula  beneath  the  flexor  pollicis  longus ;  be- 
hind and  a  little  above  the  outer  ankle,  it  divides  into  the 
anterior  and  posterior  peroneeal  arteries ;  the  former  per- 
forates the  interosseous  space  and  joins  the  external  mal- 


DUBLIN    DISSECTOR.  281 

leolar  artery;  the  latter  descends  between  the  external 
ankle  and  the  heel,  and  is  distributed  to  the  ligaments  and 
adipose  substance  in  that  region. 

The  two  plantar  branches  of  the  posterior  tibial  artery 
are  distributed  to  the  muscles  and  integuments  of  the  foot 
and  toes ;  the  internal  plantar  is  the  smaller  of  the  two,  it 
supplies  the  muscles  along  the  inner  side  of  the  tarsus ; 
the  external  plantar,  the  larger  branch,  runs  across  the  foot 
obliquely  outwards,  towards  the  fifth  metatarsal  bone,  be- 
tween the  first  and  second  layers  of  the  plantar  muscles ; 
from  the  little  toe  it  next  runs  obliquely  forwards  and  in- 
wards, towards  the  first  metatarsal  bone,  above  the  second 
layer  of  the  plantar  muscles,  and  between  the  first  and 
second  metatarsal  bones  it  joins  the  deep  branch  of  the 
anterior  tibial  artery,  and  thus  forms  the  great  plantar  arch 
of  arteries,  from  the  convexity  of  which  proceed  the  digital 
arteries,  to  supply  the  toes,  (see  Anatomy  of  the  Vascular 
System.)  The  posterior  tibial  artery  and  its  several  branch- 
es are  accompanied  by  corresponding  veins,  all  of  which 
end  in  the  popliteal  vein.  The  posterior  tibial  nerve  is  the 
principal  branch  of  the  sciatic,  it  accompanies  the  poste- 
rior tibial  artery,  at  first  lying  to  its  tibial,  afterwards  to  its 
fibular  side ;  in  this  course  it  sends  off  several  small  branch- 
es to  the  deep  and  superficial  muscles  of  the  leg,  and  be- 
tween the  heel  and  ankle  it  divides  into  the  two  plantar 
nerves,  which  take  the  course  of  the  corresponding  arte- 
ries. In  this  internal  malleolar  region,  when  the  integu- 
ments, fascia  and  internal  annular  ligament  are  removed, 
we  find  the  three  tendons  and  the  posterior  tibial  nerves 
and  vessels  to  have  the  following  relation  to  each  other,  the 
tibialis  posticus  and  flexor  communis  tendons  are  bound 
close  to  the  ankle,  about  half  an  inch  behind  these  is  the 
posterior  tibial  artery  accompanied  by  two  veins,  the  nerve 
is  a  little  nearer  to  the  heel,  and  the  tendon  of  the  flexor 
pollicis  lies  about  half  an  inch  nearer  to  the  latter. 
24* 


PART   II. 

CHAPTER  I. 

ANATOMY  OF  THE  NERVOUS  SYSTEM. 


THIS  SYSTEM  MAY  BE  DIVIDED  INTO  FOUR  PRINCIPAL  PARTS,  THE 
BRAIN,  THE  SPINAL  CORD,  THE  NERVES  AND  THE  GANGLIONS. 


SECTION  I. 

DISSECTION    OF    THE    BRAIN. 

THE  brain  is  subdivided  into  three  portions,  cerebrum, 
cerebellum,  and  'medulla  oblongata;  these  are,  however, 
so  intimately  connected,  that  it  is  difficult  to  mark  the 
exact  limits  of  each. 

Divide  the  scalp  from  one  ear  across  the  vertex  to  the 
other;  reflect  one  flap  over  the  face,  the  other  over  the 
back  of  the  neck  ;  make  a  circular  cut  with  the  saw  through 
the  cranium  on  a  level  with  the  cartilage  of  the  ear  on  each 
side,  anteriorly  about  an  inch  above  the  superciliary  arches, 
and  posteriorly  a  little  below  the  tubercle  of  the  os  occipitis. 
It  is  only  necessary  to  saw  through  the  outer  table  of  the 
bones,  the  elevator,  or  a  few  smart  strokes  with  the  claw 
of  the  hammer  will  then  suffice  to  crack  the  internal  table; 
(indeed  the  cranium  may  be  opened  by  the  hammer  alone, 
this  plan  however  injures  the  bones  so  much  as  to  leave 
them  of  little  use  to  the  student)  The  calvarium  being 
now  forcibly  torn  away,  the  dura  mater  is  exposed ;  the 
latter,  in  some  subjects,  adheres  so  closely  to  the  bone  as  to 
be  torn  along  with  it ;  this  a-ccident  will  injure  the  brain, 
and  may  be  avoided  by  introducing  the  handle  of  the  knife 
or  any  blunt  instrument  between  the  membrane  and  the 
bone  as  you  gradually  raise  off  the  latter.  If  the  student 
can  procure  two  subjects  it  will  facilitate  his  study  to  ex- 


DUBLIN    DISSECTOR.  283 

amine  the  brain  of  both  at  the  same  time ;  in  one  dissect 
the  parts  in  situ,  and  from  the  other  remove  the  brain  in 
the  following  manner :  commencing  anteriorly,  gently  raise 
it  from  the  base  of  the  skull,  divide  each  nerve  and  vessel 
in  succession  from  before  backwards  close  to  the  bone,  dis- 
locate the  pituitary  gland  from  the  sella  turcica,  and  cut 
through  the  tentorium ;  next  divide  the  spinal  cord  as  low 
down  in  the  neck  as  you  can  pass  the  knife  through  the 
foramen  magnum  ;  then  place  the  brain,  its  base  upwards, 
in  a  shallow  basin ;  thus  the  different  surfaces  and  struc- 
tures of  the  brain,  as  also  the  several  processes  and  sin- 
uses of  the  dura  mater,  can  be  examined  in  continuation 
with  each  other. 

The  MEMBRANES  covering  the  brain  are  three,  the  dura 
mater,  arachnoid  membrane,  and  pia  mater ;  the  first  may 
be  termed  the  fibrous,  the  second  the  serous,  and  the  third 
the  vascular  coat ;  these  tunics  also  extend  through  the  spi- 
nal canal  and  cover  the  spinal  cord. 

The  dura  mater  is  a  fibro-serous  membrane,  of  very  con- 
siderable strength  and  of  a  whitish  colowr,  sometimes  it  has 
a  bluish  tint ;  the  external  surface  adheres  intimately  to  the 
bones;  it  now  presents  a  rough  surface  and  several  red 
spots,  particularly  in  the  course  of  the  sutures ;  these  are 
owing  to  the  ruptured  vessels  which  passed  from  the  dura 
mater  to  the  bone,  the  former  being  the  internal  periosteum 
to  the  latter;  in  the  young  subject  the  connexion  between 
the  two  is  so  close  and  vascular,  that  it  is  very  difficult  to 
separate  them  in  the  recent  state,  and  when  this  is  effected 
numerous  bioody  dots  are  observable  on  each ;  this  mem- 
brane is  more  intimately  attached  to  the  bones  at  the  base 
of  the  cranium  than  in  any  other  situation,  it  there  sends 
small  processes  through  the  several  foramina,  some  of  these 
accompany  the  vessels  and  nerves,  and  are  gradually  lost 
on  them,  others  become  continuous  with  the  periosteum ; 
the  most  remarkable  of  these  processes,  next  to  that  which 
is  continued  along  the  spinal  canal,  is  one  which  passes 
through  the  foramen  lacerum  orbitale,  and  joins  the  peri 
osteum  in  the  orbit,  and  another  which  surrounds  the  optic 
nerve  and  is  united  to  the  sclerotic  coat  of  the  eye.  Several 
small  arteries  ramify  on  this  membrane,  between  it  and  the 
bones  of  the  cranium,  anteriorly  these  are  derived  from  the 
ophthalmic  and  internal  carotid  vessels ;  the  middle  artery 
of  the  dura  mater  is  the  largest,  this  is  a  branch  of  the  in- 
ternal maxillary,  it  enters  the  base  of  the  cranium  through 
the  spinous  hole  in  the  sphenoid  bone,  passes  forwards  and 
upwards  above  the  temporal  and  sphenoid  bones,  then  as- 
cends obliquely  backwards  on  the  inner  surface  of  the 
parietal  bone,  the  anterior  and  inferior  angle  of  which  it 


284  DUBLIN    DISSECTOR. 

grooves  very  deeply ;  posteriorly  the  dura  mater  receives 
several  small  arteries,  viz.  branches  from  the  occipital, 
pharyngeal  and  vertebral  arteries;  these  vessels  of  the 
dura  mater  also  supply  the  superincumbent  bones  with 
blood.  Cut  through  this  membrane  parallel  to  the  edge  of 
the  cranium,  raise  it  from  each  side  of  the  brain  towards 
the  vertex,  leaving  a  small  portion  of  it  in  the  mesial  line 
both  before  and  behind  undivided;  the  internal  surface  is 
now  seen  to  be  smooth  and  polished,  and  moistened  with  a 
fine  serous  exhalation ;  this  surface  is  the  reflected  or  the 
parietal  layer  of  the  arachnoid  membrane,  (to  be  examin- 
ed presently,)  it  adheres  so  closely  to  the  dura  mater  that 
it  is  difficult  to  separate  them  for  any  extent,  unless  previ- 
ously macerated. 

From  the  internal  surface  of  the  dura  mater  folds  or  pro- 
cesses extend  into  the  cranium,  which  divide  this  cavity  in- 
to several  compartments  and  support  and  separate  different 
portions  of  the  brain ;  these  processes  are  the  falx  cerebri 
tentorium  cerebelli  and  falx  cerebelli.  The  falx  cerebri  is 
exposed  by  gently  separating  one  hemisphere  of  the  brain 
from  the  other ;  it  commences  narrow  at  the  crista  galli 
and  the  middle  ridge  of  the  ethmoid  bone,  thence  it  ascends 
in  the  median  line,  and  passing  backwards,  ends  by  being 
continued  into  the  tentorium ;  the  convex  edge  of  this  pro- 
cess corresponds  to  the  middle  ridge  or  groove  of  the  os 
frontis,  to  the  sagittal  edge  of  the  two  parietal  bones,  and 
to  the  perpendicular  ridge  of  the  occipital ;  the  great  lon- 
gitudinal sinus  is  enclosed  between  the  layers  of  this  pro- 
cess, the  whole  extent  of  this  edge  ;  the  concave  or  inferior 
border  of  the  falx  corresponds  to  the  middle  line  of  the 
corpus  callosum,  from  which  it  is  but  a  very  short  dis- 
tance ;  the  inferior  or  lesser  longitudinal  sinus  is  enclosed 
in  this  edge ;  the  falx  divides  the  cavity  of  the  cranium  in 
the  median  line,  it  separates  the  hemispheres  of  the  cere- 
brum, and  in  different  positions  of  the  body  supports  the 
weight  of  each  ;  in  old  subjects  it  is  often  cribriform,  and 
in  some  it  is  partly  converted  into  bone. 

[I  have  a  specimen  of  ossification  of  the  falx  cerebri  taken  from  a 
subject,  that  died  of  apoplexy.] 

The  tentorium  cerebelli  extends  in  somewhat  a  horizontal 
direction  across  the  posterior  part  of  the  cranium;  it  may 
be  seen  by  gently  raising  the  back  part  of  either  hemis- 
phere of  the  brain ;  the  convex  edge  of  this  fold  is  attach- 
ed to  the  transverse  ridge  of  the  occipital  bone,  to  the  in- 
ferior angle  of  the  parietal  bones,  to  the  superior  angle  of 
the  petrous  bones,  and  to  the  posterior  clinoid  processes  of 
the  sphenoid ;  over  this  last  attachment,  the  concave  edge 


DUBLIN    DISSECTOR.  285 

of  the  tentorium  glides  and  is  inserted  into  the  anterior  cli- 
noid  processes ;  the  tentorium  is  raised  and  held  in  a  state 
of  tension  along  the  median  line  by  the  falx,  its  inferior 
surface  is  concave ;  anteriorly  it  presents  a  large  oval 
opening,  which  is  on  a  plane  anterior  to  the  foramen  mag- 
num, this  is  filled  by  the  superior  vermiform  process  of  the 
cerebellum,  the  crura  cerebri,  and  the  pons  varolii ;  along 
the  convex  edge  of  the  tentorium,  between  its  layers,  are 
two  sinuses  on  each  side,  the  great  lateral  and  the  superior 
petrous;  in  the  median  line  also  is  another  called  the 
straight  sinus,  which  extends  along  the  base  of  the  falx ; 
the  tentorium  serves  to  support  the  weight  of  the  cerebrum 
off  the  cerebellum. 

The  falx  cerebelli  is  seen  when  the  brain  is  removed  ;  it  is 
a  small  but  thick  process  of  little  importance,  the  base  is 
superiorly  attached  to  the  tentorium,  the  apex  inferiorly,  at 
the  foramen  magnum  :  its  convex  edge  adheres  to  the  oc- 
cipital spine,  and  contains  between  its  layers  the  occipital 
sinuses ;  its  concave  edge  separates  the  hemispheres  of  the 
cerebellum  ;  this  process  serves  to  retain  the  tentorium  and 
falx  cerebri  in  a  state  of  tension.  Attached  to  the  lesser 
wing  of  the  sphenoid  bone,  on  each  side,  is  a  slight  fold  of 
dura  mater,  termed  the  sphenoidal  fold ;  these  serve  to  in- 
crease the  surface  of  the  anterior  fossse  of  the  base  of  the 
cranium,  and  correspond  to  the  fissures  of  Sylvius  at  the 
base  of  the  brain.  The  uses  of  the  dura  mater  are,  first,  to 
serve  as  a  periosteum ;  second,  to  cover  the  brain ;  third, 
by  its  processes  to  separate  and  support  the  different  parts 
of  this  organ ;  fourth,  to  form  sheaths  for  several  of  the 
nerves  as  they  leave  the  cranium ;  and  fifth,  to  form  the 
sinuses  which  may  be  next  examined. 

The  sinuses  correspond  to  the  veins,  or  in  fact  they  are 
veins  enclosed  between  the  laminse  of  the  dura  mater, 
which  thus  retain  them  in  their  situation,  and  enable  them 
to  resist  distention;  the  principal  sinuses  are  sixteen  in 
number,  viz.  the  superior  and  inferior  longitudinal,  the 
straight,  the  right  and  left  lateral,  the  superior  and  inferior 
petrous,  the  right  and  left  cavernous,  the  circular,  the  trans- 
verse, the  occipital,  and  the  torcular  Herophili.  The  supe- 
rior longitudinal  sinus  commences  at  the  crista  galli,  either 
in  a  small  cul  de  sac,  or  by  a  small  vein  from  the  nose ;  it 
extends  upwards  and  backwards  along  the  median  line,  in- 
creasing in  size,  and  opposite  the  tubercle  of  the  os  occipi- 
tis  it  divides  into  the  right  and  left  lateral  sinuses,  the  right 
branch  being  in  general  the  larger;  with  the  scissors  lay 
open  this  sinus  through  its  whole  length ;  it  appears  some- 
what triangular,  lined  by  a  smooth  fine  membrane,  which 
is  continuous  with  that  lining  the  venous  system ;  in  gene- 


286  DUBLIN    DISSECTOR. 

ral  it  is  usually  dilated  near  the  vertex ;  small  white  fibrous 
bands  cross  it  in  many  places  ;  these  have  an  imperfect  re- 
semblance to  the  valves  of  veins  ;  and  may  serve  to  resist 
distention  of  the  sinus :  they  have  been  named  corda  Wil- 
lisii;  about  the  middle  of  this  sinus  there  are  in  general  a 
number  of  small  whitish  bodies,  sometimes  lying  singly, 
but  more  frequently  in  clusters,  near  the  openings  of  some 
of  the  veins  in  the  sinus,  these  are  termed  glandultz  Pac- 
chioni;  their  size,  number,  and  appearance,  diifer  consider- 
ably in  different  subjects ;  in  the  very  young  there  are  few, 
if  any ;  in  the  old,  they  are  most  numerous,  and  often  so 
very  large,  as  to  cause  considerable  depressions  in  the 
frontal  and  parietal  bones ;  they  are  found  in  three  situa- 
tions, in  the  cavity  of  the  sinus,  external  to  the  dura  mater, 
or  internal  to  it ;  the  first  are  termed  the  glandulae  mediae, 
the  second,  the  external,  and  the  third  the  internae ;  their 
use  or  structure  is  unknown,  most  probably  they  are  by  no 
means  allied  to  the  glandular  system.  The  longitudinal 
sinus,  like  all  the  other  sinuses,  consists  of  two  tunics,  the 
internal  or  the  venous  membrane,  and  the  external  or 
fibrous  coat  derived  from  the  dura  mater ;  this  membrane 
is  described  as  dividing  into  two  layers  on  either  side  of 
the  cavity ;  one  continues  to  adhere  to  the  bone,  and  the 
other  laminae  descend  on  either  side  of  the  sinus,  and  unite 
in  the  falx ;  the  base  of  the  triangular  cavity  thus  formed 
is  towards  the  bone,  the  apex  towards  the  falx ;  in  addition 
to  many  small  veins,  from  the  bones  and  from  the  dura 
mater,  this  sinus  receives  near  the  vertex  eight  or  ten  large 
veins  from  the  upper  surface  of  each  hemisphere  of  the 
brain,  these  run  obliquely  forwards  between  the  coats  of 
the  sinus,  some  for  an  inch,  others  for  less,  before  they 
open  into  the  cavity,  and  just  as  they  are  terminating,  they 
turn  slightly,  so  that  their  mouths  look  inwards,  or  towards 
those  of  the  opposite  side ;  all  the  veins  which  enter  the 
sinus  do  not  take  the  oblique  course  now  described,  and 
which  is  most  probably  designed  to  impede  the  reflux  of 
the  blood  from  the  sinus  into  the  cerebral  veins.  The  in- 
ferior longitudinal  sinus  is  not  always  present,  it  resembles 
a  small  vein  enclosed  in  the  lower  edge  of  the  falx  near  its 
base,  it  receives  small  veins  from  the  corpus  callosum,  and 
ends  in  the  following;  the  straight  sinus,  is  situated  in  the 
median  line,  enclosed  between  the  laminae  of  the  base  of 
the  falx  and  above  the  tentorium,  it  receives  the  blood  from 
the  lateral  ventricles  returned  by  the  two  venae  Galeni ; 
this  sinus  proceeds  backwards,  and  downwards  and  ends  in 
the  confluence  of  the  two  lateral  and  longitudinal  sinuses; 
it  presents  internally  the  same  fibrous  appearance  as  the 
great  longitudinal  sinus.  The  lateral  are  the  largest  sinuses. 


DUBLIN     DISSECTOR.  287 

of  somewhat  an  elliptical  figure,  each  proceeds  at  first  hori- 
zontally outwards  and  forwards,  enclosed  between  the  lami- 
na? of  the  tentorium,  in  a  groove  in  the  occipital  bone,  and  in 
the  inferior  angle  of  the  parietal ;  it  then  descends  inwards 
along  the  mastoid  portion  of  the  temporal  bone,  and  again 
indenting  the  occipital,  it  turns  forwards,  and  passing 
through  the  foramen  lacerum  posterius,  ends  in  the  inter- 
nal jugular  vein. 

[It  occasionally  happens  that  both  lateral  sinuses,  do  not  follow  the 
course  here  described,  but  that  one  of  them  descends  along  the  falx. 
cerebelli,  nearly  to  the  foramen  magnum,  of  the  os  occipitis,  and  then 
diverges  so  as  to  reach  the  foramen  lacerum  posterius,  being  situated 
upon  the  occipiial  bone  through  its  entire  course.  I  have  a  specimen 
of  this  kind  on  the  right  side,  and  Meckel  states  that  this  anomaly  is 
generally  found  on  the  right  side.] 

Each  lateral  sinus  receives  several  small  veins  from  the 
posterior  lobes  of  the  cerebrum  and  from  the  cerebellum ; 
these  enter  the  sinus  from  without  inwards,  contrary  to  the 
current  in  the  sinus ;  through  these  sinuses  all  the  blood  is 
returned  from  the  cranium  to  the  general  system ;  there 
are  seldom  any  transverse  bands  or  glandule  Pacchioni  in 
these  sinuses.  The  following  sinuses  are  situated  on  the 
base  of  the  cranium.  The  cavernous  sinus  on  each  side  ex- 
tends from  the  anterior  clinoid  process  to  the  point  of  the 
petrous  bone  along  the  side  of  the  body  of  the  sphenoid ; 
the  dura  mater  in  this  region  divides  into  two  layers,  one 
very  thin  adheres  to  the  irregular  bony  surface  which 
bounds  this  cavity,  the  other  much  more  dense  is  reflected 
over  this  space,  and  contains  between  its  laminse  the  third 
and  fourth  nerve,  and  the  first  part  of  the  fifth :  the  oph- 
thalmic vein  which  has  passed  through  the  foramen  lace- 
rum orbitale  superius,  opens  into  the  fore  part  of  this  sinus, 
and  the  two  petrpsal  sinuses  lead  from  it  posteriorly  to  the 
lateral  sinus ;  this  sinus  is  intersected  by  tendinous  bands, 
and  presents  rather  a  cellular  or  spongy  appearance  like 
the  corpus  cavemosum  penis ;  the  internal  carotid  artery 
and  the  sixth  or  abducens  nerve  pass  through  the  cavity 
of  this  sinus,  also  several  small  branches  from  the  sympa- 
thetic;  the  venous  membrane,  however,  is  reflected  around 
each,  so  as  to  separate  them  from  the  blood ;  the  cavernous 
sinuses  communicate  through  the  following;  the  circular 
sinus  consists  of  two  small  veins,  which  lead  from  one 
cavernous  sinus  to  the  other,  the  anterior  is  beneath  the 
optic  commissure,  and  before  the  pituitary  glands  ;  the  pos- 
terior is  behind  and  rather  below  that  body.  The  petrosal 
sinuses  are  four  in  number,  two  on  each  side,  the  superior 
and  inferior;  they  each  lead  from  the  cavernous  sinuses 
backwards,  the  former  along  the  upper  edge  of  the  petrous 


288  DUBLIN    DISSECTOR. 

bone,  to  the  lateral  sinuses  opposite  the  inferior  angle  of 
the  parietal  bone ;  the  inferior  petrous  sinus  leads  down- 
wards and  backwards,  over  the  suture  between  the  petrous 
and  occipital  bones,  and  ends  in  the  lateral  sinus  near  its 
termination.  The  transverse  sinus  leads  from  one  inferior 
petrosal  sinus  to  the  other,  across  the  cuneiform  process  of 
the  occipital  bone.  The  occipital  sinuses  are  two  small 
canals  contained  in  the  falx  cerebelli ;  they  receive  veins 
from  the  cerebellum,  and  sometimes  from  the  vertebral 
canal,  and  open  into  the  torcular  Herophili ;  these  sinuses 
sometimes  extend  along  each  side  of  the  foramen  magnum, 
and  communicate  with  the  lateral  sinuses;  the  occipital 
sinuses  are  often  wanting.  The  torcular  Herophili  is  a  sort 
of  common  reservoir  in  which  several  sinuses  end ;  it  is 
situated  opposite  the  tuberosity  of  the  occipital  bone,  and 
enclosed  between  the  layers  of  the  falx  and  tentorium  ;  it 
is  somewhat  oval,  and  presents  six  openings,  viz.  the  late- 
ral sinus  on  each  side,  the  longitudinal  sinus  above,  the 
straight  sinus  before,  and  the  occipital  sinuses  below. 

The  second  covering  of  the  brain  is  a  serous  membrane, 
the  arachnoid,  so  fine  and  delicate  that  in  some  situations  it 
is  difficult  to  demonstrate  it ;  between  the  convolutions  of 
the  brain  it  can  be  raised  from  the  pia  mater,  which  sinks 
into  the  fissures  between  these ;  and  a  little  air  forced  be- 
tween these  membranes  will  separate  them  for  some  dis- 
tance, and  will  raise  the  arachnoid  membrane  in  a  vesicular 
form ;  on  the  base  of  the  brain,  and  in  the  spinal  canal,  it 
is  stronger,  and  can  be  distinctly  detached  from  the  subja- 
cent membrane.  The  arachnoid  membrane  covers  the 
whole  surface  of  the  brain,  and  is  thence  reflected  to  the 
dura  mater,  which  it  lines  throughout,  except  at  the  sella 
turcica,  where  the  pituitary  gland  intervenes  between  these 
membranes ;  from  the  surface  of  the  brain  it  is  reflected 
on  the  dura  mater  in  several  situations,  viz.  superiorly,  as 
the  veins  enter  the  longitudinal  sinus,  this  membrane  ac- 
companies them  from  the  brain  to  the  sinus,  it  is  then 
reflected  to  the  inner  surface  of  the  dura  mater  :  inferiorly, 
also,  it  surrounds  the  nerves  in  their  course  from  the  brain 
to  the  foramina,  through  which  they  pass,  and  is  then  re- 
flected on  the  dura  mater,  the  latter  membrane  being  really 
perforated  and  continued  for  a  short  distance  around  each 
nerve,  whereas  the  arachnoid  membrane  forms  a  cul  de  sac 
at  the  exit  of  each  ;  thus  the  arachnoid  membrane,  like  all 
serous  membranes,  forms  a  shut  sac,  one  side  or  layer  of  it 
(the  parietal)  adhering  to  the  dura  mater  ;  the  other  (the 
visceral)  covering  the  brain  and  extending  from  one  emi- 
nence to  another,  without  penetrating  between  them ;  it  is 
smooth,  polished  and  transparent,  without  any  distinct 


DULLIN    DISSECTOR.  289 

vessels  ;  it  exhales  and  again  absorbs  a  fine  serous  halitus 
which  allows  the  opposed  surfaces  to  move  against  each 
other  without  friction ;  this  membrane  is  also  continued 
into  the  cavities  or  ventricles  of  the  brain,  and  gives  to 
them  a  smooth  lining.  To  see  this  process  of  the  arach- 
noid membrane,  separate  gently  the  posterior  lobes  of  the 
cerebrum,  divide  the  falx,  and  at  the  'anterior  edge  of  the 
tentorium  the  two  venee  Galeni  will  be  seen  entering  the 
straight  sinus;  these  veins  are  surrounded  by  the  serous 
membrane  ;  press  these  gently  to  one  side,  and  underneath 
them  a  small  round  hole  or  canal  may  be  observed,  leading 
forwards  below  these  veins,  and  above  the  pineal  gland, 
and  opening  into  the  back  part  of  the  third  ventricle ;  this 
canal  is  lined  by  the  arachnoid  membrane,  which  is  con- 
tinued from  that  on  the  surface  of  the  brain,  and  expands 
within  the  ventricles,  so  as  to  cover  all  the  inequalities  ob 
served  within  them ;  this  arachnoid  canal,  or  the  canal  of 
Bichat,  will  be  noticed  again  in  the  examination  of  the  ven- 
tricles. The  third  tunic  of  the  brain  is  the  vascular  coat,  or 
the  pia  mater,  of  a  very  soft  and  delicate  structure,  loaded 
with  numerous  fine  vessels  ;  it  adheres  to  the  whole  surface 
of  the  brain,  and  following  every  involution  of  its  surface, 
it  is  intimately  united  with  its  substance  by  numerous 
shreds  and  vessels,  wnich  admit  of  being  drawn  out  like 
fine  threads ;  on  the  convolutions  of  the  brain  it  is  insepa- 
rably connected  to  the  arachnoid  membrane,  but  in  most 
other  situations,  particularly  at  the  base  of  the  brain,  they 
are  but  loosely  united  to  each  other.  The  pia  mater  is  also 
prolonged  into  the  lateral  ventricles,  through  an  extensive 
fissure,  which  will  be  seen  in  the  dissection  of  the  brain 
between  the  fornix  and  the  corpus  callosum  above,  and  the 
tubercula  quadrigemina  and  pons  Varolii  below ;  this  fis- 
sure descends  obliquely  forwards  on  each  side  into  the  in- 
ferior cornu  of  each  lateral  ventricle  between  the  optic 
thalamus  and  the  hippocampus  major;  through  these 
lateral  prolongations  of  this  fissure,  a  process  of  the  pia 
mater  enters,  termed  the  choroid  plexus,  and  through  the 
central  or  transverse  portion  of  it,  another  process,  termed 
the  choroid  membrane  or  velum  interpositum ;  these  pro- 
cesses are  covered  by  the  arachnoid  membrane,  and  are  all 
connected  together,  as  will  be  seen  in  the  dissection  of  the 
ventricles ;  this  great  fissure  in  the  brain  is  closed  every 
where  by  the  arachnoid  membrane  on  the  surface  of  the 
brain  except  at  the  foramen  of  Bichat.  The  use  of  the 
pia  mater  is  to  form  an  exact  capsule  for  the  brain,  also 
an  extensive  surface,  on  which  the  vessels  divide  minutely, 
and  are  probably  arranged  in  some  peculiar  manner, 
previous  to  their  penetrating  the  substance  of  the  brain. 


290  DUBLIN    DISSECTOR. 

There  are  two  modes  of  dissecting  the  brain ;  first, 
by  removing  it  in  successive  slices  from  above  down- 
wards ;  and,  secondly,  from  below  upwards ;  the  first  plan 
is  best  adapted  for  studying  the  relative  anatomy  of  the 
different  parts  of  the  brain,  or  for  examining  this  organ 
pathologically ;  the  second  for  unravelling  its  structure ; 
the  student  should  practise  both,  and  first,  that  from  above 
downwards. 

DISSECTION    OF    THE    CEREBRUM. 

[The  great  volume  of  the  cerebrum  seems  to  be  characteristic  of 
man  ;  there  are  certain  inferior  animals,  in  which  the  whole  ence- 
phalic mass  is  proportionably  greater  than  in  the  human  race ;  but 
this  is  not  true  of  the  cerebrum  as  considered  by  itself,  it  being  pro- 
portionably  greater  in  man  than  in  other  animals.  This  would  cer- 
tainly seem  to  favor  the  phrenological  philosophy,  which  locates  the 
moral  and  intellectual  faculties  in  the  cerebrum,  and  the  animal  pro- 
pensities in  the  cerebellum.  In  the  horse  and  the  ox  the  weight  of 
the  cerebrum  does  not  exceed  half  that  of  the  human  subject.  The 
volume  of  the  cerebrum  is  independent  of  stature,  and  of  sex,  although 
it  was  formerly  thought  to  be  smaller  in  the  female  than  the  male. 
Again  its  volame  is  proportionably  greater  in  the  foetus  and  infant 
than  in  the  adult,  and  in  old  age  it  not  unfrequently  is  atrophied  to  a 
certain  extent.  The  weight  of  the  cerebrum  is  from  two  to  three 
pounds,  averaging  about  two  and  a  half,  the  cerebellum  being  equal 
to  from  a  seventh,  to  a  twelfth  of  the  cerebrum.  The  an tero- poste- 
rior measurement  of  the  cerebrum  is  about  six  inches,  its  greatest 
breadih  which  is  behind,  five  inches,  and  its  vertical  diameter  from 
four  to  five  inches.  It  is  said  that  the  volume  of  the  entire encephalo. 
rachidian  mass,  as  compared  with  that  of  the  nerves  connected  with 
it,  is  greater  in  man,  than  in  any  inferior  animal.] 

THE  CEREBRUM  is  the  largest  part  of  the  brain,  of  an  oval 
figure,  the  larger  end  posteriorly,  a  little  flattened  on  the 
sides,  convex  above,  and  divided  into  two  equal  portions, 
the  right  and  left  hemispheres,  by  a  deep  fissure  which  ex- 
tends along  the  median  line  ;  this  fissure  is  continued  be- 
fore and  behind  through  the  entire  depth  of  the  cerebrum, 
but  in  the  middle  it  is  bounded  below  by  the  corpus  callo- 
sum  ;  it  contains  the  falx  cerebri  and  the  arteries  of  the 
corpus  callosum;  each  hemisphere  is  convex  superiorly 
and  externally,  and  flat  internally,  or  towards  the  falx,  in- 
inferiorly  very  irregular  and  uneVen  ;  the  surface  of  each 
hemisphere  is  every  where  marked  by  a  number  of  emi- 
nences termed  the  convolutions  of  the  brain ;  these  are  of 
various  size  and  shape,  and  are  somewhat  convoluted  like 
the  intestines ;  their  round  edges  are  separated  by  fissures 
which  are  closed  by  the  arachnoid  membrane ;  these  fis- 
sures are  nearly  an  inch  deep ;  they  take  different  direc- 
tions, serpentine,  longitudinal,  and  oblique  ;  if  a  section  of 


DUBLIN    DISSECTOR.  291 

the  cerebrum  be  made,  these  fissures  will  be  found  to  be 
only  involutions  of  the  cineritious  substance  covering  the 
brain ;  each  fissure,  therefore,  is  only  a  continuation  of  the 
surface,  and  is  covered  throughout  by  the  pia  mater. 

The  cerebrum,  on  its  inferior  surface,  is  also  divided  into 
the  two  hemispheres  by  the  great  median  fissure  at  each 
extremity,  and  in  the  centre  by  a  depression  containing 
several  substances ;  each  hemisphere  inferiorly  is  divided 
into  three  lobes,  the  anterior,  small,  triangular,  flat,  or  a 
little  concave,  rests  on  the  roof  of  the  orbit,  presents  a 
deep  groove  which  lodges  the  olfactory  nerve ;  the  middle 
lobe  is  prominent,  round,  and  deep,  fills  up  the  middle  fos- 
sa in  the  base  of  the  cranium,  and  is  separated  from  the 
anterior  lobe  by  a  deep  fissure,  (Jissura  Sylvii,')  which  as- 
cends obliquely  outwards  and  backwards ;  this  fissure  cor- 
responds to  the  sphenoidal  fold  of  the  dura  mater,  and  to 
the  lesser  wing  of  the  sphenoid  bone ;  the  brain  above  it 
is  perforated  by  a  number  of  small  holes  for  the  entrance 
of  vessels  (pars  perforee  externe;)  this  fissure  contains  the 
middle  artery  of  the  brain,  and  one  origin  of  the  olfactory 
nerve. 

The  posterior  lobe  rests  on  the  tentorium,  and  is  separated 
from  the  middle  only  by  a  slight  excavation  ;  between  the 
hemispheres  we  observe,  immediately  behind  the  anterior 
extremity  of  the  median  fissure,  the  lower  end  of  the  cor- 
pus callosum  ;  posterior  to  this,  and  connected  to  it  is  the 
commissure  of  the  optic  nerves  ;  behind  this  is  a  soft  grey 
substance,  the  tuber  cinereum ;  this  is  connected  anteriorly 
to  these  nerves,  and  posteriorly  to  two  small  white  bodies 
termed  the  corpora  mamiUaria  or  albicantia :  these  are  about 
the  size  of  small  peas,  situated  behind  the  tuber  cinereum, 
and  attached  by  it  to  each  other  ;  they  are  grey  internally, 
although  white  externally,  the  anterior  pillars  of  the  fornix 
terminate  in  these.  From  the  centre  of  the  tuber  cinereum 
a  thin  conical  tube  of  a  reddish  colour  descends,  the  infun- 
dibulum ;  this  passes  behind  and  rather  beneath  the  com- 
missure of  the  optic  nerves ;  it  terminates  on  the  surface  of 
the  pituitary  gland ;  it  is  surrounded  by  arachnoid  mem- 
brane ;  it  is  not  pervious  inferiorly  ;  above  it  communicates 
with  the  third  ventricle.  The  pituitary  body  is  placed  in 
the  sella  Turcica  between  the  dura  mater  and  arachnoid 
membrane ;  transversely  oval,  composed  anteriorly  of  a 
yellowish  substance,  which  is  notched  before,  and  convex 
behind  like  a  kidney,  and  posteriorly  of  a  whitish  semi- 
fluid or  pulpy  substance.  Behind  the  corpora  albicantia, 
we  next  observe  a  small  triangular  depression,  closed 
above  by  a  thin  plate  which  forms  the  posterior  part  of  the 
floor  of  the  third  ventricle ;  this  is  the  middle  perforated  plate 


292  DUBLIN    DISSECTOR. 

of  the  brain ;  on  either  side  of  this  is  the  cms  cerebri,  con- 
necting the  cerebrum  to  the  pons  Varolii,  which  last  is  situ- 
ated in  the  median  line  behind  the  last  described  substances ; 
behind  the  pons  is  the  posterior  extremity  of  the  corpus 
callosum,  and  between  these  eminences  is  the  great  trans- 
verse fissure  which  transmits  the  pia  mater  into  the  ventri- 
cles, and  which  also  contains  the  arachnoid  canal  and  the 
pineal  gland  ;  behind  this  we  observe,  lastly,  the  posterior 
extremity  of  the  median  fissure  separating  the  posterior 
lobes  of  the  cerebrum. 

Cut  off  the  upper  part  of  one  hemisphere  nearly  on  a 
level  with  the  corpus  callosum,  the  appearance  now  pre- 
sented is  termed  the  centrum  minus  ovale,  a  mass  of  white 
substance  surrounded  by  the  irregularly  undulating  line  of 
grey  substance  ;  a  small  cavity  or  fissure  may  now  also  be 
observed  between  the  corpus  callosum  and  the  lower  and 
internal  margin  of  each  hemisphere :  next  slice  off  both 
hemispheres  on  a  level  with  the  corpus  callosum,  and  the 
centrum  magnum  ovale  is  presented,  that  is,  a  line  of  grey 
substance  surrounding  the  central  mass  of  white  substance. 
The  grey  or  cortical  or  cineritious  substance  of  the  brain  is 
soft  and  pulpy,  and  more  vascular  than  the  white  ;  on  the 
surface  of  the  cerebrum  it  is  about  the  eighth  of  an  inch 
in  thickness ;  in  other  situations  it  is  placed  in  considerable 
masses,  and  covered  by  the  white  substance ;  the  shade  of 
its  colour  differs  in  different  parts  of  the  brain,  and  in  dif- 
ferent subjects  :  in  the  child  it  is  reddish,  in  the  old  it  is 
grey  or  ashy.  It  consists  of  a  number  of  very  minute  glo- 
bules, connected  together  by  the  pia  mater  mand  vessels. 
The  white  or  medullary  substance  is  more  firm,  and  when 
fresh,  has  some  elasticity,  and  in  many  parts  appears  dis- 
tinctly fibrous;  its  divided  surface  appears  dotted  with  red 
spots ;  these  are  the  divided  vessels,  they  vary  in  number 
and  in  size  in  different  subjects :  in  a  very  fresh  brain, 
when  a  section  has  been  made  of  this  white  substance,  it 
will,  by  its  elasticity,  force  the  blood  to  exude  out  for  some 
little  time  in  small  drops  from  the  divided  vessels.  The 
corpus  callosum  is  now  seen  in  the  median  line  of  the  cere- 
brum, but  nearer  the  frontal  than  the  occipital  bone,  be- 
tween three  or  four  inches  long,  convex,  white,  marked  by 
two  or  three  raised  longitudinal  lines  close  and  nearly  pa- 
rallel to  each  other,  (the  raphe^  from  these  several  trans- 
verse lines  [linea  transverse]  pass  to  either  side  ;  its  poste- 
rior end  broad,  round,  and  a  little  concave,  is  bent  down- 
wards, and  is  continuous  on  either  side  with  the  fornix  and 
the  hippocampi ;  its  anterior  end  is  also  round,  and  bent 
downwards  and  backwards,  is  continued  on  each  side  into 
the  anterior  lobes,  and  in  the  middle  it  joins  the  tuber  cine- 


DUBLIN    DISSECTOR.  293 

reum  and  the  optic  commissure  ;  the  corpus  callosum  con- 
nects the  white  fibrous  substance  of  the  hemispheres,  and 
is  therefore  properly  called  the  great  commissure  of  the 
cerebrum  ;  it  covers  the  lateral  ventricles,  the  septum  luci- 
dum,  and  the  fornix.  Divide  this  substance  at  a  little  dis- 
tance from  either  side  of  the  raphe,  the  lateral  ventricles 
will  be  opened,  press  the  middle  portion  of  the  corpus  cal- 
losum to  one  side,  and  the  septum  lucidum  may  be  seen 
descending  in  the  median  line  from  it  to  the  upper  surface 
of  the  fornix.  The  septum  lucidum  separates  the  two  late- 
ral ventricles,  and  is  triangular,  the  apex  behind,  the  base 
before,  the  upper  edge  connected  to  the  corpus  callosum  ; 
the  lower  edge  to  the  fornix  posteriorly,  and  anteriorly  to 
the  inferior  curved  portion  of  the  corpus  callosum ;  it  con- 
sists of  four  lamina?,  two  on  each  side,  grey  externally, 
white  internally  ;  between  the  white  laminae  a  small  cavity 
exists  termed  the  fifth  ventricle.  This  cavity  is  naturally 
closed,  but  when  the  corpus  callosum  is  divided  trans- 
versely, and  the  anterior  portion  raised  forwards,  the  la- 
minae of  the  septum  separate,  and  this  cavity  becomes  dis- 
tinct ;  it  i-s  larger  in  the  child,  but  it  is  very  irregular  in 
size,  and  even  in  existence,  in  different  subjects ;  the  sep- 
tum lucidum  appears  to  be  formed  by  a  lamina  descending 
from  each  side  of  the  raphe  of  the  corpus  callosum  to  the 
fornix,  some  grey  matter  superadded.  Divide  transversely 
the  septum  lucidum  and  corpus  callosum,  raise  forwards 
the  anterior  portion  of  the  latter,  and  backwards  its  poste- 
rior part ;  it  will  now  be  seen  that  this  substance  is  united 
to  the  fornix  posteriorly,  but  is  nearly  an  inch  above  it.  an- 
teriorly ;  the  septum  lucidum  is  generally  so  soft  that  in 
this  stage  of  the  dissection  it  will  have  nearly  broke  down 
into  the  surrounding  fluid. 

The  lateral  ventricles  extend  from  the  middle  of  the  brain 
into  the  anterior  and  posterior  lobes,  also  to  the  inferior 
part  of  the  middle  lobe,  hence  they  are  named  tricorne ;  the 
anterior  cornu  of  each  passes  forwards  and  outwards,  they 
are  about  an  inch  distant  from  each  other ;  the  middle  por- 
tion, or  the  body  of  each,  passes  horizontally  backwards, 
they  are  separated  from  each  other  by  the  septum  luci- 
dum ;  near  the  posterior  part  of  the  corpus  callosum  the 
posterior  and  inferior  cornua  pass  off  in  different  direc- 
tions; the  posterior  cornu  proceeds  into  the  posterior  lobe 
al  first  outwards,  afterwards  it  turns  inwards  in  a  curved 
direction,  the  concavity  towards  the  median  line ;  the  infe- 
rior cornu  descends  obliquely  forwards  and  outwards  into 
the  middle  lobe,  and  is  then  also  curved  a  little  inwards  ;  it 
terminates  behind  the  fissure  of  Sylvius  and  beneath  the 
anterior  cornu.  The  anterior  cornu  is  bounded  superiorly 
25* 


294  DUBLIN    DISSECTOR. 

and  laterally  by  the  corpus  callosum,  and  inferiorly  by  the 
large  extremity  of  the  corpus  striatum  ;  the  middle,  or  body 
of  each,  is  bounded  superiorly  and  externally  by  the  cor- 
pus callosum  ;  internally  by  the  septum  lucidum,  and  in- 
feriorly by  the  posterior  extremity  of  the  corpus  striatum, 
the  toenia  semicircularis,  the  optic  thalamus,  the  choroid 
plexus,  and  the  fornix.  The  posterior  cornu  is  bounded 
superiorly  and  laterally  by  the  medullary  substance,  and 
inferiorly  by  the  hippocampus  minor.  The  inferior  cornu 
is  bounded  superiorly  by  the  optic  thalamus,  externally  by 
medullary  substance ;  internally  it  is  deficient  of  cerebral 
substance,  and  is  closed  by  the  arachnoid  membrane  ;  infe- 
riorly by  the  hippocampus  major  and  corpus  finabriatum 
or  tsenia  hippocampi. 

The  several  bodies,  observed  in  the  different  regions  of 
these  cavities,  must  next  be  examined  individually  ;  and 
first,  corpora  striata.  These  pyriform  bodies  have  their 
larger  ends  directed  forwards  and  inwards  ;  their  posterior 
small  and  pointed  extremities  pass  backwards  and  out- 
wards ;  smooth  and  unattached  superiorly  and  internally, 
on  all  other  sides  they  are  continuous  with  the  white  sub- 
stance, vascular,  soft,  and  cineritious  on  their  surface  ; 
they  will  be  found,  when  cut  into,  to -consist  of  alternate 
laminae  of  grey  and  white  substance;  the  latter  may  be 
traced  from  the  crura  cerebri  through  these  bodies  to  the 
upper  and  anterior  part  of  the  cerebrum,  hence  the  cor- 
pora striata  are  named  by  some  the  anterior  or  superior 
ganglions  of  the  cerebrum.  The  tccnia  semi-circularis,  is  a 
narrow,  semitransparent  band,  whitish,  fibrous,  placed  in 
the  groove  between  the  optic  thalamus  and  corpus  stria- 
tum ;  it  arises  narrow  from  a  tubercle  on  the  back  part  of 
the  optic  thalamus,  (corpus  geniculatum  externum,)  passes 
forwards  and  inwards,  becomes  broader,  and  joins  the  de- 
scending pillar  of  the  fornix;  the  anterior  portion  has  a 
resemblance  to  the  cornea,  and  has  been  named  lamina 
cornea :  several  veins  from  the  corpus  striatum  pass  be- 
neath the  tcenia  to  join  the  vense  Galeni.  The  choroid  plexus 
is  a  fold  of  thin  vascular  membrane  derived  from  the  pia 
mater;  it  enters  the  inferior  cornu  between  the  optic  tha- 
lamus and  the  tcenia  hippocampi;  loose  and  floating  it  as- 
cends obliquely  backwards  over  the  hippocampus  major, 
then  turns  forwards  between  the  thalamus  and  the  fornix, 
beneath  which  it  is  connected  to  the  choroid  membrane, 
and  ends  by  uniting  with  its  fellow  in  the  foramen  com- 
mune anterius ;  each  choroid  plexus  is  covered  by  the 
arachnoid  membrane  ;  they  receive  a  number  of  veins  from 
the  parietes  of  the  ventricles,  particularly  from  the  corpora 
striata ;  these  veins  join  the  vence  Galeni,  which  will  be 


DUBLIN    DISSECTOR.  295 

noticed  presently ;  very  frequently  small  vesicles,  hydatids, 
and  even  small  hard  tumours  may  be  found  in  these  mem- 
branes. 

The  fornix,  white,  fibrous,  triangular,  is  situated  horizon, 
tally,  beneath  the  corpus  callosum  and  septum  lucidum 
attached  to  the  former  posteriorly,  to  the  latter  anteriorly 
it  lies  on  the  velum  interpositum  and  choroid  plexuses, 
the  base,  posteriorly,  arises  by  two  flat  bands,  (the  posterior 
pillars  or  crura,)  one  from  either  side,  by  three  roots,  from 
the  hippocampus  major  and  minor,  and  from  the  tamia  hip- 
pocampi;  these  crura  pass  forwards  and  inwards,  and 
unite  (the  body  of  the  fornix ;)  this  bends  forwards  and  down- 
wards, over  the  foramen  -commune  anterius,  and  divides 
into  two  short,  round,  white  cords,  (the  anterior  pillars  of  the 
fornix,(  these  descend  behind  the  anterior  commissure,  and 
end  in  the  corpora  mamillaria,  which  are  connected  to  the 
grey  substance  of  the  tuber  cinereum  ;  the  inferior  surface 
of  the  fornix  which  rests  on  the  velum  is  marked  posterior- 
ly by  several  fine  oblique  lines  (lyra  or  corpus  psalloides.} 
Although  the  septum  lucidum  is  a  partition  between  the 
lateral  ventricles,  yet  these  cavities  communicate  together, 
as  also  with  the  third  or  middle  ventricle,  through  an  open- 
ing termed /oramen  commune  anterius ;  this  is  situated  in  the 
median  line  at  the  anterior  part  of  the  body  of  each  ven- 
tricle, it  is  bounded  superiorly  and  anteriorly  by  the  for- 
nix, posteriorly  by  the  two  choroid  plexuses  and  velum, 
laterally  it  leads  from  one  lateral  ventricle  to  the  other, 
and  inferiorly  it  opens  into  the  third.  The  optic  thalami 
cannot  be  fully  examined  at  present.  In  the  posterior  cor- 
nu  of  each  ventricle  is  a  small  eminence,  the  hippocampus 
minor,  large  anteriorly,  small  and  pointed  behind,  white  on 
the  surface,  grey  internally.  In  the  inferior  cornu  we  see 
the  hippocampus  major,  a  large  white  substance,  convex  ex- 
ternally, concave  internally,  smooth  and  white  on  the  sur- 
face, grey  within,  extending  all  along  the  floor  of  the  cavi- 
ty, and  ending  in  a  tuberculated  expansion,  the  pes  hippo- 
campi; along  its  internal  or  concave  edge,  and  connected 
to  it,  is  a  narrow  white  band,  the  t&nia  hippocampi  or  cor- 
pus fimbriatum,  the  concave  edge  of  which  is  loose  ;  this 
substance  is  directly  continuous  with  the  posterior  pillar 
of  the  fornix;  beneath  the  tasnia  hippocampi,  a  narrow  ci- 
neritious  line  may  be  observed,  shorter  than  the  tainia,  its 
edge  is  serrated  ;  this  is  the  corpus  denticulatum.  Divide  the 
fornix  about  its  centre,  draw  forwards  its  anterior  portion, 
and  the  foramen  commune  anterius  will  be  seen  ;  throw 
the  posterior  portion  backwards,  and  the  choroid  membrane 
or  the  velum  interpositum  will  be  exposed ;  this  is  of  a  trian- 
gular form,  beneath  the  fornix,  and  above  the  arachnoid 


296  DUBLIN    DISSECTOR. 

canal,  the  optic  thalami,  the  pineal  gland,  and  the  third  ven- 
tricle ;  the  choroid  plexuses  are  united  to  it  laterally  and 
in  front,  the  verm  Galeni  extend  along  its  median  line  ;  these 
veins  receive  the  blood  from  each  plexus,  and  from  the  dif- 
ferent eminences  in  the  ventricles,  they  pass  backwards, 
and  end  in  the  straight  sinus,  they  sometimes  first  unite  in- 
to one  trunk ;  the  velum  is  formed  of  pia  mater,  which  is 
continued  from  the  surface  of  the  brain  through  the  great 
transverse  fissure,  which  is  beneath  the  corpus  callosum 
and  the  fornix,  and  above  the  tubercula  quadrigemina  and 
the  pineal  gland  ;  it  is  also  covered  by  the  arachnoid  mem- 
brane, which  is  of  extreme  delicacy  ;  raise  this  membrane 
from  before  backwards,  first  dividing  the  small  veins  which 
run  into  it,  the  optic  thalami  will  be  now  exposed,  and  pos- 
terior to  these  the  pineal  gland,  and  the  superior  surface 
of  the  tubercula  quadrigemina  ;  the  anterior  extremity  of 
the  arachnoid  canal  also  is  seen ;  this  orifice  is  beneath  the 
veins  of  Galen  and  above  the  gland ;  it  is  in  general  sur- 
rounded by  small  granulations ;  remove  the  velum.  The 
pineal  gland  is  situated  above  the  tubercula  quadrigemina, 
behind  and  between  the  thalami,  about  the  size  of  a  pea, 
cineritious,  heart-shaped,  the  base  anteriorly  containing,  in 
general,  some  small  sandy  particles  (the  acervulus,)  the  pos- 
terior part  is  soft  and  pulpy,  (the  conarium)  is  surrounded 
by  a  very  vascular  membrane  derived  from  the  velum; 
unconnected  to  the  brain  in  every  situation,  except  ante- 
riorly, whence  a  small  transverse  medullary  band  proceeds, 
which  divides  into  two  long  delicate  processes,  (pedunculi,) 
these  pass  forwards  on  the  inner  surface  of  the  optic  thala- 
mi, and  join  the  descending  pillars  of  the  fornix,  at  the  fo- 
ramen commune  anterius.  The  optic  thalami,  two  firm  bo- 
dies white  on  their  surface,  grey  within,  placed  behind  and 
between  the  corpora  striata,  smooth  superiorly  where  they 
enter  into  the  lateral  ventricles,  touching  each  other  inter- 
nally, where  they  are  soft  and  grey ;  this  connexion  is 
termed  the  commissura  mollis,  it  is  a  broad,  soft,  and  cineri- 
tious union  between  the  internal  surfaces  of  the  thalami, 
and  anterior  to  their  centre,  this  must  be  broken  through 
before  the  third  ventricle  can  be  seen ;  a  sort  of  fissure  se- 
parates the  thalami  ;  this  fissure  anteriorly  leads  to  the  fo- 
ramen commune  anterius,  and  posteriorly  to  the  foramen 
commune  posterius,  this  last  hole  is  behind  the  soft  commis- 
sure, and  between  the  peduncles  of  the  pineal  gland,  it  is, 
however,  so  closed  by  the  velum  and  the  forndx.  that  no 
communication  can  occur  through  it  between  the  third  and 
the  two  lateral  ventricles,  as  through  the  anterior  common 
opening;  the  optic  thalami  externally  and  anteriorly  are 
continuous  with  the  corpora  stiata  and  the  medullary  sub- 


DUBLIN    DISSECTOR.  297 

stance  of  the  hemispheres ;  inferiorly  they  present  two  tu- 
bercles ;  (corpus  geniculatum  internum  and  externum;")  their  an- 
terior extremity  is  in  the  foramen  commune  anterius,  their 
posterior  is  in  contact  with  the  corpus  fimbriatum  ;  the  up- 
per surface  of  each  is  in  the  body  of  the  lateral  ventricle,  the 
inferior  surface  is  in  the  inferior  cornu ;  through  the  sub- 
stance of  the  thalami  some  portious  of  the  crura  cerebri 
pass  in  their  course  to  the  convolutions  of  the  hemispheres, 
hence  they  are  named  by  some  the  inferior  ganglions  of 
the  brain.  Separate  the  optic  thalami,  and  the  third  or 
middle  ventricle  will  be  opened.  The  third  ventricle  is  a 
narrow  cavity  placed  in  the  median  line,  bounded  on  each 
side  by  the  optic  thalami,  above  by  the  velum  and  the  for- 
nix,  below  by  the  locus  perforatus  arid  tuber  cinereum,  be- 
fore by  the  descending  pillars  of  the  fornix  and  the  ante- 
rior commissure,  behind  by  the  posterior  commissure  and 
pineal  gland,  its  peduncuH  and  the  tubercula  quadrigemi- 
na.  The  foramen  commune  anterius  opens  into  the  upper 
and  anterior  part  of  this  cavity ;  the  infundibulum  leads 
from  the  lower  and  anterior  part  downwards  and  forwards, 
between  the  pillars  of  the  fornix  and  below  the  anterior 
commissure,  to  the  pituitary  gland;  this  canal  is  large 
above,  but  it  is  generally  impervious  below.  From  the  pos- 
terior part  of  the  third  ventricle  a  small  canal  leads  back- 
wards and  downwards,  above  and  behind  the  pons  Varolii, 
and  below  the  tubercula  quadrigemina,  this  is  the  aqueduct 
of  Sylvius  or  the  iter  ad  quartum  ventriculum.  The  anterior 
commissure  is  a  distinct  round  cord,  extending  from  one  he- 
misphere to  the  other,  immediately  before  the  anterior  pil- 
lars of  the  fornix,  bent  like  an  arch,  convex  anteriorly, 
unattached  in  its  central  portion,  but  on  each  side  it  is  im- 
bedded in  the  corpus  striaturn,  through  which  it  descends 
obliquely  backwards  and  outwards,  and  then  terminates  in 
rays  near  the  fissure  of  Sylvius,  and  the  inferior  cornu  of 
the  lateral  ventricle  ;  it  is  enclosed  in  a  delicate  sheath  of 
pia  mater,  like  a  nerve.  The  posterior  commissure  is  shorter 
and  smaller  than  the  anterior,  but  white,  round,  and  fibrous 
like  it ;  it  extends  transversely  behind  the  third  ventricle, 
above  the  aqueduct  of  Sylvius,  below  the  pedunculi  of  the 
pineal  gland  to  which  it  is  connected,  and  anterior  to  the 
tubercula  quadrigemina ;  its  extremities  are  connected, 
to  the  optic  thalami.  The  tubercula  quadrigemina  are  below 
and  behind  this  commissure  and  the  pineal  gland,  they  are 
all  connected  by  their  bases,  on  an  oblique  plane,  and  se- 
parated from  each  other  near  their  points  by  two  superfi- 
cial grooves,  a  transverse  and  a  vertical ;  the  two  superior 
and  anterior  are  called  the  nates,  the  two  inferior  and  pos- 
terior the  testes,  white  on  their  surface,  grey  internally ; 


298  DUBLIN    DISSECTOR. 

they  lie  above  and  behind  the  aqueduct  of  Sylvius,  which 
alone  separates  them  from  the  pons  Varolii ;  the  nates  are 
connected  to  the  optic  thalami,  and  the  testes  to  the  cere- 
bellum, by  two  thin  white  plates,  which  descend  oblique- 
ly backwards  and  outwards,  and  end  in  the  substance  of 
the  cerebellum  ;  these  are  the  processus  a  cerebello  ad  testes  ; 
they  diverge  towards  the  cerebellum,  and  are  continuous 
externally  and  interiorly  with  a  thick,  round,  white  chord, 
the  crus  cerebelli ;  between  these  two  processes  there  is  a 
thin  lamina  extended  named  the  valve  of  Vieussens,  or  of  the 
fourth  ventricle,  cineritious  and  very  soft,  triangular,  the 
apex  between  the  testes,  the  base  attached  to  the  cerebel- 
lum, and  the  sides  to  the  two  processes  just  described ;  this 
valve  forms  the  roof  of  the  fourth  ventricle,  it  is  overlapped 
by  the  superior  vermiform  process.  Pass  a  probe  along 
the  aqueduct  of  Sylvius,  divide  the  valve  of  Vieussens,  and 
the  cavity  of  the  fourth  ventricle  will  be  exposed ;  this  is 
directed  obliquely  downwards  and  backwards,  between  the 
cerebrum,  cerebellum,  and  medulla  oblongata ;  it  is  bound- 
ed anteriorly  by  the  pons  Varolii,  in  the  median  line  of 
which  is  a  narrow  fissure,  the  calamus  scriptorius,  from  each 
side  of  which  a  few  white  lines  pass  off  to  join  the  auditory 
nerve ;  laterally  by  the  processes  from  the  testes  and  by 
the  crura  cerebelli ;  superiorly  by  the  valve  of  Vieussens  ; 
posteriorly  -by  the  cerebellum,  and  inferiorly  by  the  reflec- 
tion of  the  arachnoid  membrane,  and  of  the  pia  mater  from 
the  inferior  surface  of  the  cerebellum  to  the  back  of  the 
spinal  cord ;  the  pia  mater  is  here  peculiarly  dense,  and  it 
sends  a  small  process  into  the  lower  part  of  this  cavity, 
(the  choroid  plexus  of  the  fourth  ventricle,)  which  is  loaded 
with  tortuous  vessels,  and  frequently  presents  a  small  num- 
ber of  reddish  granular  bodies. 

Raise  either  hemisphere  of  the  cerebrum ;  from  its  infe- 
rior surface,  just  below  the  corpus  striatum  and  the  optic 
thalamus,  a  thick,  white  fasciculus  may  be  observed  de- 
scending obliquely  backwards  and  inwards;  this  is  the 
crus  cerebri;  fibrous  and  white  on  the  surface,  each  crus  in- 
ternally contains  cineritious  substance  of  a  very  dark  co- 
lour (locus  niger ;)  the  crura  cerebri  converge  as  they  de- 
scend, and  end  in  the  upper  extremity  of  the  pons  Varolii ; 
the  third  ventricle  is  between  them,  and  the  tractus  opti- 
cus  of  each  side  surrounds  them.  The  crura  cerebri  and 
the  following  substance  can  be  better  examined  when  the 
brain  is  removed  from  the  subject,  and  the  base  placed  up- 
permost. The  pons  VaroJii  or  cerebral  protuberance  is 
somewhat  square,  it  is  placed  obliquely  on  the  cuneiform 
process,  between  the  cerebrum  and  cerebellum  ;  the  fourth 
ventricle,  the  aqueduct  of  Sylvius  and  the  tubercula  qua- 


DUBLIN    DISSECTOR.  299 

drigemina,  are  on  its  superior  and  posterior  surface ;  its 
inferior  and  anterior  surface  rests  on  the  bone,  and  is 
grooved  longitudinally  by  the  basiiar  artery ;  its  superior 
extremity  receives  the  crura  cerebri,  which  it  surrounds 
like  a  ring,  hence  it  is  sometimes  called  the  annular  protu- 
berance ;  the  crura  cerebelli  are  attached  to  its  sides,  and 
the  medulla  oblongata  to  its  lower  extremity,  from  which 
it  is  distinguished  by  a  deep  groove:  the  pons  is  of  a  more 
firm  structure  than  any  part  of  the  brain,  its  surface  is 
white  and  fibrous ;  the  superficial  layer  of  fibres  on  its  in- 
ferior surface  runs  transversely  from  one  crus  cerebelli  to 
the  other,  hence  the  pons  has  been  named  the  commissure 
of  the  cerebellum  ;  beneath  this  lamina  of  transverse  fibres 
a  quantity  of  cineritious  substance  exists,  through  which 
white  fibrous  substance  may  be  seen  to  ascend  obliquely 
outwards,  in  the  direction  of  the  crura  cerebri.  The  pons 
Varolii  is  described  by  some  authors  as  a  portion  of  the 
medulla  oblongata  ;  it  is,  however,  so  connected  with  it  as 
well  as  with  the  cerebrum  arid  cerebellum,  that  it  may  be 
considered  as  equally  common  to  all. 

DISSECTION    OF    THE    CEREBELLUM. 

[The  average  weight  of  the  cerebellum  is  six  ounces,  its  transverse 
diameter  averages  from  three  and  a  half  to  four  inches,  its  antero-pos- 
terior  diameter  from  two,  lo  two  and  a  half  inches,  and  its  vertical 
diameter  also  from  two,  to  two  and  a  half  inches.  These  measure, 
ments  being  made  at  its  broadest,  longest,  and  thickest  parts.  The 
average  proportion  of  the  cerebellum  to  the  cerebrum,  is  as  one  to 
seven.  The  volume  of  the  cerebellum,  is  greater  in  man  than  in  all 
other  animals.  According  to  Gall  and  Cuvier,  it  is  proportionably 
greater  in  woman,  than  in  man,  while  it  is  proportionably  less  in  the 
child,  than  in  the  adult.  It  is  also  said  by  Gall  to  be  in  proportion  to 
the  generative  function,  this  however,  Cruveilhier  considers  mere  hy- 
pothesis, because  certain  species  of  animals  remarkable  for  their  vene- 
real ardor  have  the  cerebellum  very  small,  and  because  the  inverte- 
brated  animals  have  no  cerebellum.  The  cerebellum  is  continuous, 
on  the  one  hand,  superiorly  with  the  cerebrum  through  the  processus 
a  cerebello  ad  testes  ;  on  the  other  hand,  with  the  medulla  oblongata 
through  the  corpora  restiformia,  or  processus  a  cerebello  ad  medullam 
oblongatam.  Again  a  continuity  between  the  two  hemispheres  of 
the  cerebellum,  is  established!  by  transverse  fibres,  in  the  annular  pro- 
tuberance. In  four  cases  Cruveilhier  has  seen  atrophy  of  the  right 
hemisphere  of  the  cerebrum,  and  of  the  lel'l  hemisphere  of  the  cere- 
bellum conjoined.  The  cerebellum  does  not  become  distinct  until 
after  the  medulla  spinalis,  and  the  medulla  oblongata,  and  in  the 
earliest  months  of  utero- gestation  passes  through  stages  of  develop- 
ment, which  resemble  the  cerebellum  of  fish  and  of  reptiles.] 

REMOVE  the  posterior  lobes  of  the  cerebrum,  divide  the 
tentorium,  and  the  cerebellum  will  be  exposed  ;  transverse- 


300  DUBLIN    DISSECTOR. 

ly  oval,  raised  in  the  centre,  divided  into  right  and  left  he- 
mispheres by  a  deep  groove  posteriorly  and  inferiorly,  which 
receives  the  falx  cerebelli,  and  by  a  broad  notch  anterior- 
ly which  is  behind  the  fourth  ventricle  ;  the  upper  surface 
of  each  hemisphere  is  nearly  flat,  and  is  marked  by  a  great 
number  of  narrow  lines  which  run  semicircularly,  convex 
posteriorly ;  these  are  fissures  into  which  the  pia  mater  de- 
scends, the  arachnoid  membrane  passing  over  them  ;  these 
fissures  are  analogous  to  those  in  the  cerebrum ;  they  are 
involutions  of  the  grey  substance,  the  superficial  extent  of 
which  is  thus  considerably  augmented :  the  same  appear- 
ance is  also  observable  inferiorly ;  the  lines,  however,  are 
not  so  numerous  or  regular  as  above ;  some  lines  pass  in 
very  deep  into  the  cerebellum,  and  divide  it  into  lobes, 
others  are  only  superficial :  and  divide  it  into  lobules ;  the 
inferior  surface  of  each  hemisphere  is  very  convex,  and 
fills  the  inferior  occipital  fossse.  Along  the  circumference 
of  each  hemisphere  a  deep  fissure  extends,  at  the  bottom 
of  which  a  white  cord  is  observed ;  this  is  the  cms  cerebetti, 
which  ascends  obliquely  forwards  and  inwards  to  join  the 
pons  Varolii ;  this  great  fissure  separates  the  superior  from 
the  inferior  surface.  The  central  portion  of  the  cerebel- 
lum is  narrow,  and  raised  superiorly  into  a  small  conical 
process,  the  superior  vermiform  process,  this  overlaps  the 
valve  of  Vieussens,  the  tubercula  quadrigemina,  and  the 
processus  a  cerebello  ad  testes ;  inferiorly  there  is  a  deep 
depression,  which  contains,  anteriorly,  the  commencement 
of  the  spinal  cord,  and  posteriorly  a  large  process,  the  infe- 
rior vermiform  which  is  marked  by  numerous  transverse 
lines  or  fissures,  which  divide  it  into  several  laminse  or  lo- 
bules. Divide  either  hemisphere  parallel  to,  and  about  an 
inch  from  the  median  line,  a  thick  mass  of  white  substance 
is  seen  in  the  centre,  branching  out  into  fine  fibres,  which 
extend  into  the  lobes,  and  again  subdivide  into  fine  fila- 
ments, which  pass  to  every  lamina  or  lobule  on  the  surface, 
and  are  there  covered  by  a  thin  layer  of  grey  substance  ; 
[this  arrangement  is  called  the  arbor  vitae,]  nearly  in  the 
centre  of  this  white  mass,  which  is  continuous  superiorly 
with  the  processus  ad  testem,  and  inferiorly  with  the  crus 
cerebelli,  is  a  small  oval  mass  of  grey  substance,  its  edges 
convoluted  or  serrated  ;  this  is  the  corpus  dentatum  or  rhom- 
boideum ;  the  white  substance  which  is  continued  from  the 
medulla  oblongata  to  the  crus  cerebelli,  appears  to  run 
through  this,  and  thus  to  be  increased  in  quantity  :  hence 
it  is  named  by  some  the  ganglion  of  the  cerebellum. 


DUBLIN    DISSECTOR.  301 

DISSECTION   OF   THE   MEDULLA   OBLONGATA. 

[The  medulla  oblongata  is  situated  so  as  to  extend  from  the  upper 
margin  of  the  first  cervical  vertebra,  to  the  middle  of  the  basilar 
fossa  of  the  occiput.  Its  extent  superiorly  and  anteriorly,  is  defined 
by  the  annular  protuberance,  not  so  posteriorly.  Inferiorly  it  gradu- 
ally diminishes  in  circumference,  and  is  continuous  with  the  medulla 
spinalis,  it  is  however,  limited  here  artificially,  and  is  said  to  be  from 
an  inch,  to  one  inch  and  a  quarter  in  length  ;  this  however  will  de- 
pend somewhat  upon  the  position  of  the  head,  its  breadth  is  eight  or 
nine  lines  at  its  base  and  its  thickness  six  lines.] 

THE  medulla  oblongata  is  that  conical  portion  of  white 
substance  which  extends  from  the  lower  margin  of  the 
pons  Varolii  to  the  spinal  cord,  about  an  inch  in  length, 
large  above,  narrow  below,  where  it  passes  through  the 
foramen  magnum,  divided  by  longitudinal  lines  into  six 
oval  eminences  placed  parallel  to  each  other ;  the  median 
line  anteriorly  separates  the  two  corpora  pyramidalia; 
next  to  each  of  these  is  a  slight  groove,  external  to  which 
is  the  corpus  olivare,  behind  which  is  a  groove  and  another 
eminence,  the  corpus  restiforme  or  the  posterior  pyramid. 

The  corpora  pyramidalia  are  about  an  inch  long. 

[They  extend  the  whole  length  of  the  medulla  oblongata,  being  a 
line  and  a  half  in  breadth  below,  but  gradually  increasing  until  they 
acquire  a  breadth  of  three  lines  above.] 

And  they  arise  gradually  from  the  fore  part  of  the  spinal 
cord  above  the  atlas,  ascend  parallel  to  each  other,  increase 
in  size,  enter  the  pons,  and  they  may  be  traced  through 
this  substance  for  some  extent ;  the  median  fissure,  which 
extends  along  the  spinal  cord,  separates  them ;  near  the 
pons  this  fissure  enlarges  into  a  small  hole  (foramen  cae- 
cum.) Dissect  off  the  pia  mater  from  these  eminences,  en- 
deavour to  separate  them  from  each  other,  and  about  three 
quarters  of  an  inch  below  the  pons  five  or  six  white  bands 
may  be  observed  ascending  obliquely  from  one  corpus  py- 
ramidale  to  the  other,  the  fasciculi  of  opposite  sides  per- 
fectly indigitating  with  each  other  ;  these  are  the  decussat- 
ing fibres  of  the  pyramids. 

The  corpora  olivaria  are  oval,  large  in  the  centre,  white 
on  the  surface,  and  containing  within  a  corpus  fimbriatum 
of  grey  substance;  they  are  separated  by  a  superficial 
groove  from  the  former  eminences ;  their  upper  extremity 
is  continued  into  the  pons  Varolii. 

[From  which  they  may  be  traced  into  the  thalami  nervorum  opti- 
corum.  They  are  but  six  or  seven  lines  long,  and  two  and  a  half 
lines  broad,  and  are  elevated  about  a  line.  Internally  they  are  sepa- 
rated from  the  pyramids,  by  a  slight  fissure,  in  which  are  the  roots 
of  the  hypoglossal  nerve,  and  externally  there  is  a  deep  fissure,  be. 
26 


302  DUBLIN    DISSECTOR. 

tween  these,  and  the  corpora  restiformia.  The  corpora  olivaria  are 
almost  peculiar  to  man,  they  are  found  in  other  mammalia,  but  are 
small  and  do  not  exist  in  birds,  reptiles,  and  fish.] 

The  corpora  restiformia  are  rather  larger  than  the  last,  be- 
hind which  they  are  placed ;  they  are  separated  from  each 
other  by  a  fissure  which  is  continued  from  the  calamus 
scriptorius  along  the  posterior  median  line  of  the  spinal 
cord;  the  restiform  bodies  are  continued  superiorly  into 
the  crura  cerebelli,  hence  they  are  sometimes  named  the 
processus  a  medulla  spinali  ad  cerebellum :  they  are  also 
partly  continued  into  the  crura  cerebri. 

[They  are  continuous  with  the  posterior  fissure  of  the  medulla 
spinalis,  and  on  the  upper  surface  of  the  medulla  oblongata,  is  a  re- 
markable excavation,  between  the  corpora  restiformia,  the  calamus 
scriptorius  which  is  marked  by  medullary  strise,  which  give  origin  to 
the  auditory  nerve,  and  some  of  which  Meckel,  supposes  to  be  con- 
nected  with  the  trifacial  and  pneumo-gastric  nerves.] 

ORIGIN   OF   THE   CEKEBRAL   NERVES. 

THERE  are  nine  pair  of  cerebral  nerves ;  their  connexion 
to  the  brain  is  named  their  origin ;  they  are  distinguished 
by  the  terms  first,  second,  third,  &c.,  &c. ;  in  every  respect, 
those  of  the  opposite  side  are  symmetrical. 

The  FIRST  PAIR,  or  OLFACTORY,  are  situated  beneath  the 
anterior  lobes  of  the  brain ;  each  arises  by  three  filaments, 
the  external,  very  long  and  white,  from  the  fissure  of  Syl- 
vius, below  the  corpus  striatum ;  the  internal,  also  white, 
from  the  grey  substance  at  the  extremity  of  the  corpus  cai- 
losum ;  the  middle  is  cineritious,  and  arises  from  one  of  the 
posterior  convolutions  of  the  anterior  lobe;  the  three  fila- 
ments soon  unite  and  form  a  triangular  swelling,  from 
which  the  nerve  proceeds  forwards  and  inwards  for  about 
two  inches,  in  a  groove  in  the  anterior  lobe,  in  which  it  is 
confined  by  the  arachnoid  membrane  and  protected  from 
pressure  ;  it  then  ends  in  a  soft  oval  bulb  which  is  placed 
over  the  cribriform  plate  of  the  ethmoid  bone ;  from  this 
several  fine  filaments  descend  through  the  foramina  in  this 
bone,  and  are  distributed  to  the  mucous  membrane  in  the 
nose.  The  olfactory  differ  from  the  other  cerebral  nerves 
in  figure,  course,  and  structure ;  prismatic  or  triangular, 
the  apex  is  imbedded  in  the  cerebrum ;  they  converge  as 
they  leave  the  cranium;  they  consist  of  several  striae,  some 
white,  others  grey,  all  very  soft :  they  are  not  surrounded 
by  arachnoid  membrane,  but  lie  above  it ;  they  have  no 
distinct  sheath,  and  each  ends  in  a  soft  grey  swelling  from 
which  the  ultimate  filaments  proceed,  and  which  leave  the 
cranium  by  a  number  of  foramina. 

The  SECOND  PAIR,  or  OPTIC,  are  large,  soft,  and  flat  poste- 


DUBLIN    DISSECTOR.  303 

riorly,  round  and  inclosed  in  a  dense  neurilema  anterior- 
ly ;  each  arises  by  two  bands,  one  from  the  nates,  the  other 
from  the  testis  ;  these  pass  outwards  beneath  the  optic  tha- 
lamus,  the  first  joins  the  corpus  geniculatum  externum ; 
the  second  the  corpus  geniculatum  internum ;  these  roots 
then  unite  in  a  soft  flat  band,  which  turns  forwards  in  a 
semicircular  course  (tractus  options)  around  the  crus  cere- 
bri,  to  which  it  has  a  slight  attachment,  and  from  which  it 
receives  a  few  fibres  :  the  optic  nerves  then  converge,  and 
unite  before  the  sella  turcica,  in  the  optic  commissure ;  in 
this  flat,  white,  square  substance,  which  is  connected  to 
and  receives  additional  fibres  from  the  tuber  cinereum,  the 
two  nerves  are  so  confounded  that  the  direction  of  each  is 
indistinct,  and  it  is  uncertain  whether  they  decussate  in 
whole  or  in  part ;  from  the  commissure  each  nerve  passes 
forwards  and  outwards  on  the  inner  side  of  the  carotid  and 
above  the  ophthalmic  artery,  through  the  optic  foramen, 
into  the  orbit ;  it  is  then  surrounded  by  a  process  of  dura 
mater,  and  proceeding  to  the  back  part  of  the  eye,  it  perfo- 
rates the  sclerotic  and  choroid  coats  of  this  organ,  and  ter- 
minates in  the  retina. 

The  THIRD,  or  MOTORES  OCULORUM,  are  smaller  than  the 
optic ;  each  arises  from  the  inner  side  of  the  crus  cerebri, 
close  to  the  pons,  behind  the  floor  of  the  third  ventricle, 
and  between  the  posterior  artery  of  the  cerebrum,  and  the 
anterior  artery  of  the  cerebellum ;  this  round  nerve  passes 
forwards  and  outwards  external  to  the  cavernous  sinus, 
through  the  foramen  lacerum  orbitale,  and  is  distributed 
to  five  of  the  seven  muscles  contained  in  the  orbit. 

The  FOURTH,  or  TROCHLEATORES,  or  PATHETICI,  are  the 
smallest  of  the  cerebral  nerves ;  each  arises  by  two  or  three 
delicate  filaments  from  the  valve  of  Vieussens  and  from 
the  processus  a  cerebello  ad  testem ;  it  takes  a  long  course 
forwards  and  outwards  between  the  cerebrum  and  cerebel- 
lum, enters  a  small  canal  between  the  layers  of  the  tento- 
rium  behind  the  posterior  ciinoid  process,  and  continues 
its  course  along  the  outer  side  of  the  cavernous  sinus 
through  the  foramen  lacerum  orbitale  to  the  superior  ob- 
lique muscle. 

The  FIFTH,  or  TRIFACIAL,  or  TRIGEMINI,  are  the  largest  of 
the  cerebral  nerves ;  each  consists  of  nearly  one  hundred 
fine  filaments,  but  loosely  connected  to  each  other,  and 
very  easily  detached  from  the  brain :  arises  by  two  fasci- 
culi, one,  large  and  posterior,  from  the  angle  between  the 
pons  Varolii  and  the  crus  cerebelli,  the  other,  small  and 
anterior,  from  the  corpus  pyramidale  in  the  substance  of 
the  pons ;  these  pass  together  forwards  and  outwards  over 
the  point  of  the  petrous  bone  in  a  sort  of  canal  formed  of 


304  DUBLIN    DISSECTOR. 

dura  mater,  and  lined  by  arachnoid  membrane,  which  last 
is  reflected  on  the  nerve,  so  as  to  form  a  cul  de  sac  around 
it ;  in  the  middle  fossa  of  the  base  of  the  cranium  it  ex- 
pands into  a  large  grey  swelling,  (the  triangular,  semilunar, 
or  Casserian ganglion;}  this  ganglion  is  concave  posteriorly ; 
convex  anteriorly  and  externally ;  the  dura  mater  covers 
and  adheres  intimately  to  its  plexiform  surface ;  three  large 
branches  proceed  from  it,  the  ophthalmic,  the  superior  and 
inferior  maxillary ;  the  first  passes  into  the  orbit  through  the 
foramen  lacerum ;  the  second  leaves  the  cranium  by  the 
foramen  rotundum,  and  the  third  by  the  foramen  ovale.  If 
the  ganglion  be  raised  from  the  bone,  a  small  fasciculus  of 
fibres  may  be  observed  to  pass  from  the  trunk  of  the  fifth 
pair,  without  entering  into  the  ganglion,  to  the  inferior 
maxillary  nerve ;  this  fasciculus  can  be  traced  into  the  an- 
terior root  of  the  fifth,  or  through  the  pons  Varolii  into  the 
corpus  pyramidale. — When  this  nerve  is  detached  from  the 
brain,  a  small  nipple-like  tubercle  is  seen  on  the  latter  at 
the  point  of  separation.  The  fifth  pair  of  nerves  resemble 
the  spinal  nerves,  in  arising  by  two  roots,  and  in  having  a 
ganglion  placed  on  the  posterior,  to  which  the  anterior  is 
only  connected. 

The  SIXTH,  or  ABDUCENTES,  are  of  a  middle  size  between 
the  third  and  fourth  ;  each  arises  from  the  outer  side  of  the 
corpus  pyramidale,  a  little  below  the  pons,  it  passes  for- 
wards and  outwards,  pierces  the  dura  mater  behind  the 
body  of  the  sphenoid  bone,  traverses  the  cavernous  sinus 
on  the  outer  side  of  the  carotid  artery,  and  is  there  joined 
by  two  or  three  small  filaments  from  the  superior  cervical 
ganglion  of  the  sympathetic  nerve,  it  then  enters  the  orbit 
through  the  foramen  lacerum,  and  is  distributed  to  the  ex- 
ternal rectus  muscle ;  the  basilar  artery  is  between  the 
sixth  pair  of  nerves. 

The  SEVENTH  PAIR  consists  of  two  portions,  the  PORTIO 
DURA,  or  the  FACIAL  nerve,  and  the  PORTIO  MOLLI-S,  or  the 
AUDITORY  nerve.  The  facial  nerve  is  the  anterior  and 
smaller  of  the  two,  it  arises  from  the  lower  edge  of  the  side 
of  the  pons  below  the  crus  cerebelli,  and  behind  and  above 
the  corpus  olivare. 

The  auditory  nerve,  or  portio  mollis,  is  the  posterior  and 
the  larger,  it  arises  by  three  or  four  strise  from  the  side  of 
the  calamus  scriptorius  and  from  a  small  mass  of  grey  sub- 
stance on  the  back  cf  the  corpus  restiforme ;  these  are  at 
first  separated  by  the  restiforme,  but  soon  unite  into  one 
soft  white  cord,  which  passes  forwards  and  outwards  and 
joins  the  portio  dura ;  the  two  nerves  then  pass  outwards, 
the  mollis  being  larger  than  the  dura,  which  is  contained 
in  a  groove  in  the  former,  and  a  small  blood  vessel  runs 


DUBLIN    DISSECTOR.  305 

between  them ;  they  both  enter  the  meatus  auditorius  in- 
ternus,  where  they  soon  separate ;  the  facial  nerve  runs 
along  the  aqueduct  of  Fallopius,  which  canal  opens  infe- 
riorly  at  the  stylo-mastoid  foramen ;  this  nerve  then  turns 
forwards,  and  is  distributed  to  the  side  of  the  face ;  the 
auditory  nerve  descends  obliquely  forwards,  and  is  distri- 
buted to  the  cochlea  and  semicircular  canals. 

The  EIGHTH  PAIR,  or  PAR  VAGUM,  consists  of  three  por- 
tions, the  GLOSSO-PHARYNGEAL  the  smallest,  the  PNEUMO- 
GASTRIC  the  largest,  and  the  SPINAL  ACCESSORY,  which  is  of 
a  medium  size. 

The  glosso-pharyngeal  arises  by  four  or  five  delicate  fila- 
ments between  the  corpus  olivare  and  restiforme;  these 
unite  into  one  small  nerve. 

The  pneumo-gastric,  or  the  vagus,  arises  by  ten  or  twelve 
filaments  below  the  last,  but  in  the  same  groove ;  these 
also  unite  into  one  nerve,  which,  with  the  glosso-pharyn- 
geal, passes  forwards  and  outwards  to  the  foramen  lace- 
rum  posterius  or  jugulare,  where  they  are  joined  by  the 
third  portion. 

The  spinal  accessory  nerve  arises  from  the  side  of  the  me- 
dulla spinalis  by  several  delicate  roots  or  fibres,  which 
commence  a  little  above  the  middle  of  the  cervical  portion 
of  this  organ. 

(Sometimes  these  roots  commence  as  far  down  as  opposite  the 
seventh  cervical  nerve  ;  there  are  also  three  or  four  filaments  from 
the  medulla  oblongata.] 

This  nerve  ascends  behind  the  ligamentum  denticulatum, 
and  very  near  the  posterior  roots  of  the  spinal  nerves ;  it 
frequently  receives  filaments  from  the  roots  of  these  nerves : 
having  passed  through  the  foramen  magnum  it  joins  the 
other  divisions  of  the  eighth  pair,  the  inferior  artery  of  the 
cerebellum  having  previously  passed  between  them.  The 
eighth  pair  of  nerves  passes  through  the  jugular  foramen 
anterior  to  the  vein  and  immediately  separates  into  its  three 
portions,  the  particular  course  of  each  of  which  shall  be 
considered  afterwards.  The  spinal  accessory  is  distributed 
to  the  muscles  on  the  side  of  the  neck  ;  the  glosso-pharyn- 
geal to  the  pharynx  and  the  tongue,  and  the  pueumo-gas- 
tric  to  the  lungs  and  stomach. 

The  NINTH  or  LINGUAL  nerve  arises  by  six  or  eight  fine 
filaments  between  the  corpus  olivare  and  pyramidale,  and 
behind  the  vertebral  artery;  these  unite  and  pass  through 
the  lingual  or  anterior  condyloid  hole  in  the  occipital  bone. 
The  ninth  pair  of  nerves  are  distributed  to  some  of  the  in- 
ferior muscles  of  the  neck,  also  to  those  of  the  tongue. 

Nerves  are  either  simple  or  compound ;  by  simple  is  meant 
26* 


306  DUBLIN    DISSECTOR, 

a  nerve  possessed  of  but  one  property ;  by  compound,  a 
nerve  possessed  of  two  properties.  The  properties  with 
which  nerves  are  endowed,  so  far  as  we  are  positively  in- 
formed, are  two,  viz.  sensation  and  volition ;  nerves  endowed 
with  the  former  are  called  sensitive  nerves,  the  latter  are  the 
voluntary  nerves  or  nerves  of  motion.  Of  the  nine  pair  of  cere- 
bral nerves  some  are  simple,  some  compound,  the  simple 
are  the  first,  second,  third,  fourth,  sixth,  and  ninth ;  the  first 
and  second  are  simple  nerves  of  sense ;  the  third,  fourth, 
sixth  and  ninth,  are  simple  nerves  of  motion.  The  fifth, 
seventh,  and  most  probably  the  eighth,  are  all  compound 
nerves,  thus  the  ganglionic  portions  of  the  fifth  are  sensi- 
tive, while  the  non-ganglionic  are  motor ;  the  portio  mollis 
of  the  seventh  is  sensitive,  but  the  portio  dura  is  motor. 
The  peculiar  position  of  the  origin  of  the  eighth  from  the 
side  of  the  medulla  oblongata  and  spinal  cord  would  imply 
that  it  partook  of  the  double  properties  of  these  organs, 
that  is,  of  their  anterior  and  posterior  surface,  and  that  it 
was  a  compound  nerve,  and  accordingly,  in  experiments 
on  living  and  on  recently  killed  animals,  irritation  applied 
to  the  divisions  of  the  eighth  pair,  has  in  the  former  state 
of  the  animal  produced  pain,  and  in  the  latter  muscular 
contraction. 

[The  cranial  or  cerebral  nerves,  are  so  called  because  they  pass  out 
of  the  foramina,  of  the  cranium,  and  not  as  the  name  would  imply  be- 
cause they  all  arise  from  the  cerebrum,  for  we  have  just  seen  that 
many  of  them  arise  from  the  medulla  oblongata,  and  in  one  case  even 
from  the  medulla  spinalis  low  down.  The  nine  pair  of  nerves,  above 
described  are  named  by  Willis  and  others  indifferently,  according  to 
to  their  origin,  from  before  backwards,  numerically,  or  according  to 
their  distribution  and  uses.  There  is  however  a  defect  in  the  above 
arrangement,  for  we  find  that  the  seventh  pair  as  described,  includes 
two  nerves  entirely  distinct  in  their  distribution  and  uses  :  again  the 
eighth  pair  comprehends  three  distinct  nerves,  accordingly  Soemmer- 
ing  modified  the  nomenclature  as  follows. 

First  pair,  Olfactory  nerves. 

Second  pair,  Optic  nerves. 

Third  pair,  Motores  Communes  Oculorum. 

Fourth  pair,  Trochleatores,  or  Pathetici 

Fifth  pair,  Trigemini,  or  Trifacial. 

Sixth  pair,  Abducentes,  or  Motores  Externi. 

Seventh  pair  Portio  Dura,  or  Facial  nerve. 

Eighth  pair,  Portio  Mollis,  or  Auditory  nerve, 

Ninth  pair,  Glosso-Pharyngeal. 

Tenth  pair,  Par  Vagum,  or  Pneumo  Gastric. 

Eleventh  pair,  Spinal  Accessory. 

Twelfth  pair,  Sublingual,  or  Hypoglossal. 

This  appears  to  be  much  the  best  arrangement,  except  that  the 
spinal  accessory  nerve  should  be  considered  as  the  twelfth  pair,  in 


DUBLIN    DISSECTOR.  307 

consequence  of  its  arising  low  down  from  the  medulla  oblongata,  and 
medulla  spinalis. 

In  accordance  with  the  present  state  of  our  knowledge  of  the  de- 
velopment of  the  nervous  system,  as  regards  priority,  we  ought  to 
examine  the  cranial  nerves  from  behind  forwards,  instead  of  from  be- 
fore backwards,  and  in  this  more  philosophic  point  of  view  the  spinal 
accessory,  would  be  the  first  pair.  The  present  more  common  mode 
of  examining  them  is,  however,  the  most  convenient.] 

Before  the  student  dissects  the  cerebral  nerves  to  their 
termination,  he  may  examine  the  spinal  marrow,  and  also 
dissect  the  brain  from  below  upwards. 


CHAPTER    II 


DISSECTION  OF  THE  MEDULLA  SPINALIS. 

THE  spinal  marrow  is  contained  or  rather  suspended  in 
a  cavity  or  canal  much  larger  than  itself,  and  which  is 
bounded  by  the  bodies  and  processes  of  the  vertebrae  and 
by  their  connecting  ligaments ;  this  organ,  like  the  brain, 
is  surrounded  by  three  membranes,  which  are  continuous 
with  those  in  the  cranium.  Place  the  subject  on  the  fore 
part,  remove  the  soft  parts  covering  the  spine,  and  with  the 
saw  divide  the  crura  of  the  spinous  processes  of  all  the  ver- 
tebras close  to  their  articulating  processes,  then  with  the 
elevator  raise  the  posterior  arch  of  the  spinal  canal;  a 
quantity  of  loose  reddish  cellular  tissue,  and  the  numerous 
vertebral  venous  sinuses,  intervene  between  the  bones  and 
the  dura  mater,  which  membrane  is  loosely  connected  to 
them,  and  cannot  therefore  serve  the  office  of  periosteum 
as  in  the  cranium ;  it  is  more  closely  attached  to  the  liga- 
ments and  bones  anteriorly,  than  laterally  or  posteriorly. 

The  dura  mater  of  the  spinal  canal  is  termed  the  theca 
vertebralis ;  it  is  continued  from  the  cranium  through  the 
foramen  magnum,  down  the  spinal  canal  as  far  as  the  third 
lumbar  vertebra,  where  it  divides  into  several  processes, 
which  are  continued  on  the  sacral  nerves ;  throughout  this 
extent  it  regularly  sends  off  a  tubular  process  along  each 
of  the  spinal  nerves ;  its  external  surface  is  smooth  and 
polished.  With  the  scissors  divide  this  membrane  along 
its  whole  length  ;  its  internal  surface  will  be  found  lined 
by  the  reflected  layer  of  the  arachnoid  or  serous  membrane. 

The  arachnoid  or  the  serous  membrane  in  this  region  has  a 
corresponding  appearance  to  that  in  the  cranium;  it  is. 


308  DUBLIN    DISSECTOR. 

however,  rather  stronger,  and  more  loosely  connected  to 
the  pia  mater,  so  that  air  or  any  fine  fluid  may  be  impelled 
between  them ;  a  quantity  of  serous  fluid  is  also  naturally 
interposed,  so  that  this,  unlike  other  serous  membranes, 
must  possess  two  exhalant  and  absorbent  surfaces.  From 
the  sides  of  the  spinal  marrow  it  is  regularly  reflected 
along  each  of  the  nerves  of  the  dura  rnater ;  these  several 
reflections  or  folds,  when  examined  in  succession,  are  found 
to  be  continuous  with  each  other,  and  assist  in  forming  the 
following  substance,  the  ligamentum  denticulatum ;  this  is  a 
narrow  membranous  and  ligamentous  band  extending  along 
each  side  of  the  whole  spinal  cord ;  its  superior  extremity 
is  attached  to  the  dura  mater  at  the  foramen  magnum ;  its 
internal  edge  is  straight,  and  is  connected  to  the  pia  mater 
along  the  side  of  the  spinal  cord  in  the  space  between  the 
anterior  and  posterior  roots  of  the  spinal  nerves  ;  its  exter- 
nal edge  is  serrated  and  attached  by  several  pointed  pro- 
cesses to  the  inner  surface  of  the  dura  mater,  near  the  fora- 
mina for  the  passage  of  the  nerves ;  each  of  these  processes 
lies  between  the  anterior  and  posterior  fasciculi  of  the 
nerves ;  its  inferior  extremity  is  inserted  into  the  ligamen- 
tous substance  on  the  body  of  the  fourth  or  fifth  lumbar 
vertebra.  The  ligamentum  denticulatum  serves  to  separate 
the  roots  of  the  spinal  nerves,  also  to  connect  or  fix  the 
spinal  cord  laterally,  and  so  guard  against  concussion  or 
displacement  of  the  cord. 

The  pia  mater  in  the  spinal  canal  is  more  dense  than  in 
the  cranium,  it  adheres  so  closely  to  the  spinal  cord  as  to 
appear  to  compress  it,  which  is  evident  when  the  cord  is 
cut  across ;  it  is  not  so  uniformly  vascular  as  it.  is  on  the 
brain,  very  large  and  tortuous  vessels  however  extend  along 
its  whole  length. 

The  MEDULLA  SPINALIS  extends  from  the  foramen  mag- 
num, where  it  is  continuous  with  the  medulla  oblongata  as 
far  as  the  second  lumbar  vertebra,  where  it  ends  in  a  lash 
of  nerves  called  cauda  equina ;  this  organ  is  almost  cylin- 
drical ;  its  transverse  diameter  exceeds  the  aotero-poste- 
rior  ;  a  deep  narrow  fissure  extends  along  the  median  line 
posteriorly,  and  a  broad  superficial  groove  anteriorly ;  at 
first  the  medulla  spinalis  is  rather  contracted  or  smaller 
than  the  medulla  oblongata ;  but  from  the  fourth  or  fifth 
cervical  to  the  first  dorsal  vertebra  it  is  larger  than  in  any 
other  situation ;  it  then  contracts  through  the  upper  ana1 
middle  dorsal  regions,  and  again  swells  out  about  the  tenth 
dorsal  vertebra  into  an  oval  bulbous  expansion  which  ter- 
minates at  the  second  lumbar  vertebra  in  a  point,  from 
which  the  remains  of  the  ligamenta  dentata  extend ;  this 
lower  extremity  of  the  spinal  cord  is  sometimes  round, 


DUBLIN    DISSECTOR.  309 

sometimes  bifid.  The  two  enlargements  of  the  spinal  cord 
correspond  to  the  origins  of  the  largest  nerves,  viz.  those  to 
supply  the  upper  and  the  lower  extremity.  The  medulla 
spinalis  appears  to  consist  of  two  symmetrical  portions 
united  at  the  bottom  of  the  two  fissures  by  transverse  bands 
or  commissures, 

[Which  are  three  in  number,  anterior,  posterior  and  middle.  Be- 
sides these  commissures,  there  is  a  distinct  decussation  of  the  anterior 
columns,  for  the  space  of  four  or  five  lines  near  the  occipital  foramen, 
a.  fact  of  much  pathological  value.] 

If  either  side  be  divided  by  a  transverse  section,  it  will 
be  found  to  consist  of  grey  and  white  substance,  the  latter 
placed  externally,  the  former  internally,  and  of  a  lunated 
appearance,  the  concavity  looking  outwards ;  some  grey 
substance  is  also  placed  transversely,  and  connects  the 
convexities  of  these  lateral  masses.  The  younger  the  sub- 
ject the  more  distinct  is  the  cineritious  substance  in  the 
spinal  cord.  The  medullary  substance  on  each  side  ap- 
pears to  be  arranged  in  three  columns,  separated  by  super- 
ficial grooves :  from  these  the  spinal  nerves  proceed,  and 
it  has  been  ascertained  by  Majendie  and  Bell,  that  the  pos- 
terior roots  of  these  nerves  are  endowed  with  sensation 
only,  and  that,  the  anterior  are  connected  with  voluntary 
motion ;  Bell  also  intimates,  but  without  sufficient  proof, 
that  the  middle,  or  those  which  arise  from  the  sides  of  the 
cord,  preside  over  the  function  of  respiration. 

[There  is  a  remarkable  difference  in  the  relative  situation  of  the 
medulla  spinalis,  as  placed  in  the  vertebrated  and  invertebrated  ani- 
mals. In  the  former  it  is  superior,  or  posterior  to  the  alimentary 
canal,  in  the  latter  it  is  inferior.  In  length  the  medulla  spinalis  mea- 
sures from  fifteen  to  twenty  inches,  according  to  the  stature  of  the 
individual ;  its  breadth,  where  most  contracted  is  about  one  inch,  and 
at  its  widest  parts  one  inch  and  a  half.  Its  length  also  depends 
somewhat  upon  the  position  of  the  subject,  for  it  is  elongated  during 
the  flexion  of  the  spine,  arid  retracts  again  during  extension  ;  this 
variation  is  estimated  by  Cruveilhier,  at  from  twelve  to  fifteen  lines. 
Neither  does  the  medulla  fill  the  whole  circumference  of  the  canal, 
but  there  is  a  space  between  the  arachnoid  tunic,  and  the  dura 
mater  filled  by  the  cerebro- spinal  fluid,  this  arrangement  protects  the 
medulla  from  compression,  during  the  varied  movements  of  the  spine. 
The  medulla  spinalis  is  usually  described,  as  ending  opposite  the  first 
or  second  lumbar  vertebra,  but  it  sometimes  descends  as  low  as  the 
third,  and  has  been  seen,  to  end  opposite  the  eleventh  dorsal  vertebra. 
Thus  we  find  that  its  length  is  not  proportioned  to  that  of  the  spinal 
canal;  in  the  earlier  months  of  foetal  life,the  medulla  extends  down  to 
the  sacrum.  In  vertebrated  animate  the  volume  of  the  medulla 
spinalis  as  compared  with  the  size  of  the  animal,  is  in  direct  ratio 
with  its  vital  activity,  hence  it  is  small  in  fish  and  reptiles,  large  in 
birds  and  mammalia.  According  to  Soemruering,  its  volume  in  man, 


310  DUBLIN    DISSECTOR. 

relatively  to  the  encephalon,  is  smaller  than  in  other  animals,  but  in 
proportion  to  the  size  of  his  body,  man  has  a  larger  medulla  than  any 
other  animal  except  birds. 

Chaussier  says  that  the  volume  of  the  medulla,  is  equal  to  from  a 
nineteenth  to  a  twenty-fifth  part  of  that  of  the  cerebrum,  in  the  adult, 
but  that  in  the  new  born  infant  it  is  but  one  fortieth.  The  volume  of 
the  spinal  marrow  at  particular  points,  is  in  proportion  to  the  size  and 
number  of  the  nerves  connected  with  it,  and  the  energy  of  function, 
in  those  organs,  to  which  these  nerves  are  distributed  ;  and  the  func- 
tion of  sensation  is  connected  with  nerves  of  greater  size  than  those 
connected  with  muscular  contraction.  We  find  that  the  cervical  en- 
largement of  the  spinal  marrow,  is  greater  than  the  lumbar,  for  two 
reasons,  the  one  because  the  superior  extremity  possesses  a  greater 
extent  and  variety  of  motion  than  the  inferior,  and  the  other,  because 
these  same  extremities  are  the  organs  of  touch.] 

In  addition  to  the  spinal  accessory  nerves,  which  may  be 
now  seen  to  arise  from  each  side  of  the  medulla  spinalis  in 
the  upper  half  of  the  neck  by  twelve  or  fourteen  small  fila- 
ments, and  to  ascend  behind  the  ligarnenta  denticulata,  the 
spinal  cord  gives  origin  to  at  least  thirty  pair. 

ORIGIN   OF   THE     SPINAL   NERVES. 

The  spinal  nerves  are  symmetrical ;  there  are  thirty 
pair,  (some  anatomists  enumerate  thirty-one  or  thirty-two,) 
which  are  divided  into  eight  cervical,  twelve  dorsal,  five 
lumbar,  and  five  sacral ;  all  these  nerves  arise  and  termi- 
nate nearly  in  a  similar  manner;  each  spinal  nerve  is  at 
first  composed  of  two  roots,  an  anterior  and  posterior,  each 
of  which  consists  of  several  filaments,  which  arise  from 
the  anterior  and  posterior  surface  of  the  spinal  cord  on 
either  side  of  the  median  fissures;  these  filaments  unite 
into  fasciculi ;  those  composing  the  posterior  root  are 
larger  than  those  in  the  anterior,  (excepting  in  the  case  of 
the  first  or  sub-occipital,  whose  anterior  is  equal  or  even 
larger  than  the  posterior ;)  these  two  fasciculi  or  roots  are 
separated  from  each  other  by  the  side  of  the  spinal  cord, 
and  by  the  ligamentum  dentatum  ;  they  can  converge  and 
proceed  obliquely  outwards  and  downwards  to  the  dura 
rnater,  which  they  perforate  distinctly  by  two  small  open- 
ings, which,  however,  are  so  close,  as  to  appear  but  one ; 
each  fasciculus  receives  a  sheath  from  the  dura  mater,  they 
then  pass  through  the  inter- vertebral  foramen,  and  in  this 
situation  a  small  oval  ganglion  is  formed  upon  the.  posterior 
root  of  each,  to  the  surface  of  this  ganglion  the  anterior 
root  is  only  connected ;  immediately  on  the  outer  side  of 
this  ganglion  the  two  roots  unite  and  form  a  single  cord  ; 
this  is  the  proper  spinal  nerve ;  after  a  short  course  out- 
wards, this  divides  into  two  branches,  a  posterior  and  an 


DUBLIN    DISSECTOR.  311 

anterior  ;  the  former  is  almost  universally  the  smaller,  ex- 
cept in  the  case  of  the  second  cervical,  and  is  distributed 
to  the  muscles  and  integuments  posterior  to  the  vertebral 
column ;  the  anterior  branches  of  the  spinal  nerves  are 
much  larger ;  they  enter  into  several  plexuses,  and  supply 
the  muscles  anterior  to  the  spinal  column,  as  also  the  ex- 
tremities. The  superior  cervical  nerves  take  nearly  a 
transverse  course  from  their  origin  to  the  inter- vertebral 
foramina ;  the  succeeding  nerves  are  more  oblique,  and 
the  lumbar  and  sacral  take  a  longitudinal  course,  and  form 
their  ganglions  and  subsequent  divisions  within  the  spinal 
canal. 

All  the  spinal  nerves  are  compound  nerves,  but  their 
roots  are  simple,  the  anterior  being  motor,  and  the  poste- 
rior sensitive. 

The  course  and  distribution  of  the  spinal  nerves  shall  be 
examined  individually  afterwards,  the  student  may  next 
dissect  the  brain  from  below. 

DISSECTION   OF   THE   BRAIN   FROM   BELOW. 

THE  brain,  medulla  oblongata,  and  the  upper  part  of  the 
spinal  cord  should  be  carefully  removed  from  the  subject ; 
the  brain,  with  the  base  uppermost,  should  then  be  placed 
in  a  shallow  basin  ;  the  cerebellum  and  medulla  oblongata 
will  now  fall  a  little  backwards,  and  all  the  parts  of  the 
base  of  the  brain  will  be  exposed.  Raise  the  pia  mater 
from  the  forepart  and  sides  of  the  medulla  oblongata  ;  the 
several  eminences  on  this  organ  may  be  traced  upwards  to 
the  cerebrum,  or  to  the  cerebellum :  to  follow  these,  the 
dissector  should  rather  scrape  the  surrounding  substance 
with  the  handle  or  with  the  back  of  the  knife,  then  cut  it 
with  the  edge.  In  the  description  of  the  brain  already 
given,  certain  differences  between  the  cineritious  and  the 
white  substances  have  been  stated  ;  it  is  necessary  to  recol- 
lect that  the  former  is  soft,  vascular,  and  pulpy,  and  that 
the  latter  is  fibrous ;  it  is  an  opinion  entertained  by  many, 
particularly  Gall  and  Spurzheim,  that  the  grey  is  the  origin 
or  matrix  of  the  white  substance,  or  that  the  former  is  a 
secreting  organ,  and  the  latter  consists  of  fine  conducting 
vessels  or  filaments :  the  direction  of  the  fibres  in  some 
situations  is  very  distinct ;  some  pass  from  below  upwards 
and  outwards  ;  these  are  termed  diverging  fibres,  others  pass 
from  the  surface  or  circumference  downwards  and  inwards, 
these  are  the  converging  or  uniting  fibres:  first  proceed  to 
trace  these  two  orders  of  fibres  in  the  cerebellum. 


312  DUBLIN    DISSECTOR. 


STRUCTURE   OF   THE   CEREBELLUM. 

TRACE  the  restiform  body  upwards  into  the  cms  cerebelli ; 
divide  this  substance  vertically,  and  the  former  may  be 
seen  continued  into  the  mass  of  grey  substance  in  the  crus 
known  by  the  name  of  corpus  dentatum,  or  the  ganglion 
of  the  cerebellum ;  from  the  inner  edge  of  this  a  narrow 
white  fasciculus  may  be  traced  inwards  towards  the  medi- 
an line ;  it  there  unites  with  a  similar  process  from  the  op- 
posite side,  and  both  divide  into  several  fine  bands,  which 
diverge  and  form  the  vermiform  process,  (or  the  primary 
portion  of  the  cerebellum ;)  the  peripheral  extremities  of 
these  fibres  are  covered  by  cineritious  substance,  and  pre- 
sent, when  cut  vertically,  an  arborescent  appearance;  the 
remainder,  or  the  principal  portion  of  the  restiform  body, 
passes  upwards  and  outwards  through  the  corpus  dentatum, 
and  then  divides  into  several  processes  or  stalks  which  di- 
verge through  each  hemisphere  and  sub-divide  into  finer 
branches,  each  of  which  is  covered  by  the  grey  substance 
on  the  surface ;  a  vertical  section  of  either  hemisphere 
presents  also  that  arborescent  appearance  known  by  the 
name  of  arbor  vitse.  The  converging  fibres  of  the  cere- 
bellum are  inferior  and  superior ;  the  latter  are  very  deli- 
cate and  rather  indistinct  in  their  course ;  they  consist  of 
several  fibres  which  issue  from  the  vermiform  process  and 
unite  in  one  broad  lamina  which  is  thin  in  the  centre,  (the 
valve  of  Vieussens,)  and  thick  at  each  side  (processus  a 
cerebello  ad  testem ;)  thus  these  superior  converging  fibres 
form  the  superior  or  lesser  commissure  of  the  cerebellum, 
they  also  connect  the  cerebellum  to  the  quadrigeminal 
bodies.  The  inferior  converging  fibres  are  more  distinct, 
they  proceed  from  the  cineritious  substance  in  either 
hemisphere  forwards  and  inwards,  and  form  the  principal 
portion  of  each  crus  cerebelli ;  they  then  pass  transverse- 
ly across  the  pons  Varolii  and  unite  with  those  from  the 
opposite  side  ;  thus  the  superficial  lamina  or  the  transverse 
fibres  of  the  pons  form  the  great  or  inferior  commissure 
between  the  hemispheres  of  the  cerebellum. 

STRUCTURE  OF  THE  CEREBRUM. 

REMOVE  the  pia  mater  from  the  anterior  pyramids  of  the 
medulla  oblongata,  and  separate  these  from  each  other, 
the  decussating  fibres  will  be  seen ;  through  these  the  py- 
ramid on  one  side  may  be  said  to  arise  from  the  spinal  cord 
of  the  opposite  side ;  as  the  pyramids  approach  the  pons 
they  are  somewhat  contracted  ;  on  entering  this  substance 
they  separate  into  fasciculi,  which  intermix  with  cineri- 
tious substance  ;  they  are  considerably  increased  in  size  and 


DUBLIN    DISSECTOR.  313 

number  in  passing  through  the  pons,  and  they  then  form 
the  anterior  and  external  two-thirds  of  the  crura  cerebri. 
The  olivary  body  and  a  few  fibres  from  the  restiform  ot 
each  side  also  ascend  through  the  pons  behind  the  fasci- 
culi of  the  pyramids  ;  these  also  increase  in  size  in  passing 
through  the  pons,  and  then  enter  the  crura  cerebri,  the 
posterior  and  internal  part  of  which  they  form.  Each  crus 
cerebri  contains  a  mass  of  cineritious  substance  of  a  pecu- 
liarly dark  colour,  in  passing  through  which  the  white 
fibres  appear  increased  in  quantity.  The  posterior  and 
internal  fasciculi  of  each  crus  ascend  and  pass  into  those 
masses  of  grey  substance  called  the  optic  thalami,  and  the 
corpora  striata ;  in  passing  through  these  their  fibres  are 
increased  in  number,  and  thence  extend  in  a  radiated  man- 
ner into  the  posterior  and  superior  convolutions  of  each 
hemisphere,  where  they  are  covered  by  a  layer  of  grey 
substance.  The  anterior  and  external  portion  of  each  crus, 
which  is  in  continuation  with  the  corpus  pyramidale,  in 
like  manner  ascends  and  expands  into  fasciculi,  which  may 
be  traced  into  the  inferior,  anterior,  and  external  convolu- 
tions of  each  hemisphere.  The  uneven  surface  known  by 
the  name  of  convolutions  appears  to  depend  on  the  unequal 
length  of  these  diverging  fibres;  if  they  were  all  of  equal 
extent  the  surface  of  the  cerebrum  would  be  smooth,  but  as 
some  fall  short  of  others,  and  all  are  covered  by  the  grey 
substance,  an  uneven  or  convoluted  surface  is  the  result. 
From  this  grey  substance  which  covers  the  surface  of  each 
convolution,  the  converging  or  descending  fibres  are  de- 
scribed as  arising,  and  thence  passing  towards  the  mesial 
line  to  unite  with  those  from  the  opposite  side  ;  the  corpus 
callosum  and  the  anterior  and  posterior  commissures  are 
supposed  to  be  thus  formed  ;  in  addition  to  these  trans- 
verse processes  there  are  several  other  parts  which  may 
serve  as  media  of  communication  between  different  parts 
in  each  hemisphere  of  the  brain,  viz.  the  fornix,  the  tsenia 
semicircularis,  the  pineal  gland,  and  its  pedunculi,  the  in- 
fundibulum,  the  septum  lucidum,  &c.  &c. 

VESSELS    OF    THE    BRAIN. 

THE  brain  is  supplied  with  blood  by  the  two  vertebral, 
and  the  two  internal  carotid  arteries.  The  vertebral  arteries 
are  the  first  branches  of  the  subclavian  arteries,  they  as- 
cend through  the  series  of  foramina  in  the  transverse  pro- 
cesses of  the  cervical  vertebrae,  and  passing  through  the 
foramen  magnum  into  the  cranium,  they  proceed  obliquely 
forwards  and  inwards,  and  end  in  a  common  trunk  called 
the  basilar  artery ;  each  vertebral  first  sends  off  two  long 
and  delicate  branches,  one  on  the  anterior,  the  other  on  the 
27 


314  DUBLIN    DISSECTOR. 

posterior  surface  of  the  spinal  cord,  these  extend  the  whole 
length  of  this  organ,  supplying  it  with  blood,  and  sending 
out  small  branches  along  the  several  spinal  nerves. 

[Of  these  two  arteries,  the  latter,  the  posterior  vertebral,  continue 
the  whole  length  of  the  spinal  cord  parellel  to  each  other,  but  the 
former,  the  anterior  vertebral  arteries,  soon  after  their  origin  unite  and 
form  a  single  trunk,  which  descends  along  the  anterior  middle  fissure 
of  the  cord.] 

Next  to  these  branches  each  vertebral  gives  off  the  infe- 
rior artery  of  the  cerebellum;  this  turns  backwards  be- 
tween the  pneumogastric  and  spinal  accessory  nerves,  and 
is  distributed  to  the  inferior  surface  of  the  cerebellum. 
The  basilar  artery  ascends  along  the  median  groove  in  the 
pons,  and  at  its  superior  edge  divides  into  four  branches, 
two  for  each  side,  viz.  the  superior  cerebellar  artery  and 
the  posterior  cerebral ;  these  are  distributed  as  their  names 
imply  :  the  posterior  cerebral  artery  of  each  side  is  joined 
by  the  posterior  branch  of  each  internal  carotid ;  this 
communication  completes  the  circle  of  Willis.  Each  in- 
ternal carotid  artery  winds  obliquely  forwards,  upwards,  and 
inwards,  through  the  tortuous  canal  in  the  temporal  bone, 
and  through  the  cavernous  sinus ;  beneath  the  anterior  cli- 
noid  process  it  perforates  the  dura  mater,  and  rises  perpen- 
dicularly to  the  base  of  the  brain  between  the  second  and 
third  nerves,  and  then  divides  into  three  branches,  the  an- 
terior, middle,  and  posterior;  before  it  thus  divides  it  gives 
off,  first,  small  branches  to  the  cavernous  sinus  and  to  the 
dura  mater,  and  next  the  ophthalmic  artery  which  enters 
the  orbit  through  the  optic  hole,  and  is  distributed  to  the 
eye  and  its  appendages.  The  anterior  branch  of  the  caro- 
tid is  also  named  the  anterior  cerebral  artery,  or  the  artery 
of  the  corpus  callosum  :  this  passes  for  wards  and  inwards, 
and  is  joined  to  the  corresponding  artery  of  the  opposite 
side  by  a  short  branch,  (the  anterior  communicating  ar- 
tery,) it  then  ascends  and  runs  along  the  upper  surface 
of  the  corpus  callosum,  distributing  its  branches  to  the  in- 
ner surface  of  each  hemisphere ;  the  middle  branch  [the 
middle  cerebral  artery]  of  the  carotid  is  very  large,  it 
passes  upwards  and  outwards  deep  in  the  fissure  of  Syl- 
vius, and  is  distributed  to  the  anterior  and  middle  lobes  of 
the  cerebrum  ;  the  posterior  branch  of  the  carotid  is  named 
the  posterior  communicating  artery ;  it  is  small,  passes 
backwards,  and  joins  the  posterior  cerebral  artery ;  this 
forms  the  side  of  the  circle  of  Willis. — (See  Anatomy  of 
Vascular  System.)  The  vessels  of  the  brain  are  accompa- 
nied by  numerous  fine  filaments  of  the  sympathetic  nerve, 


DUBLIN    DISSECTOR.  315 

these  pass  into  its  substance  and  supply  its  intimate  struc- 
ture. 

The  veins  of  the  brain  join  the  sinuses  which  have  been 
already  described  ;  the  principal  veins  are  on  the  superior 
surface  of  the  brain,  whereas  the  large  arteries  are  below. 

The  brain  and  its  membranes  exhibit  many  morbid  ap- 
pearances. The  dura-mater  is  sometimes  found  in  a  state  of 
inflammation ;  to  an  inexperienced  eye  this  appearance  is 
difficult  of  detection,  as  in  this  condition,  very  few  vessels 
more  appear  carrying  florid  blood,  than  in  the  natural 
state;  in  injuries  from  external  violence,  where  inflamma- 
tion follows,  suppuration  often  occurs,  and  the  pus  is  found 
sometimes  on  its  external  surface,  between  it  and  the  bone, 
in  other  cases  the  matter  is  internal,  and  then  the  arach- 
noid coat,  lining  the  dura  mater,  is  found  covered  with  pus. 
Scrofulous  and  fungoid  or  fibrous  tumours  growing  from  the 
dura  mater,  producing  absorption  of  the  bone,  or  pressure 
on  the  brain,  are  occasionally  found :  also  a  deposition  of 
bony  lamina?  in  some  part  of  the  dura  mater,  more  parti- 
cularly in  the  falciform  process  or  near  the  superior  longi- 
tudinal sinus. 

The  arachnoid  membrane  is  sometimes  inflamed. — 
Arachnitis,  when  chronic,  presents  an  opaque  or  in  some  in- 
stances a  thickened  state  of  the  membrane,  which  gives  it 
a  tolerably  firm  consistence ;  serous  fluid,  sometimes  of  a 
gelatinous  nature,  and  creamy  appearance,  is  found  be- 
tween it  and  the  pia  mater;  and  although  these  appear- 
ances are  said  to  depend  on  inflammation,  still  no  vessels 
holding  red  blood  are  found  ramifying  on  its  surface,  the 
redness  which  is  sometimes  present,  being  owing  to  the 
vessels  of  the  pia  mater  appearing  through  it.  Adhesions 
between  the  parietal  and  visceral  lamina?  of  this  membrane 
seldom  occur,  as  in  other  serous  cavities :  in  acute  arach- 
nitis, pus,  or  sero-purulent  fluid,  or  serum  with  lymphy 
flakes  and  of  a  sanguineous  colour  is  often  effused. 

Hydroceplialus  is  a  disease  of  this  membrane  of  frequent 
occurrence,  it  consists  of  an  effusion  of  clear  serous  fluid, 
it  may  be  acute  or  chronic,  and  the  fluid,  which  may  amount 
to  a  few  ounces  or  to  as  many  pounds,  may  be  collected 
either  within  the  ventricles,  (hydrocephalus  internus,)  or  it 
may  be  on  the  surface  of  the  brain,  (hydrocephalus  exter- 
nus ;)  in  the  latter  the  brain  will  be  found  compressed  to- 
wards the  base  of  the  cranium,  in  the  former,  which  is  the 
more  common  form,  the  hemispheres  will  be  found  expand- 
ed; in  both  the  cranium  will  be  enlarged,  and  in  young 
persons  the  sagittal  and  coronal  sutures  will  be  expanded, 
and  the  fluid,  in  passing  from  one  lateral  ventricle  to  the 
other,  raises  up  the  fornix,  expands  the  foramen  commune 


316  DUBLIN    DISSECTOR. 

anterius,  and  so  passes  into  the  third  and  thence  into  the 
fourth  ventricle.  In  hydrocephalus,  scrofulous  disease  is 
frequently  to  be  found  at  the  base  of  the  brain,  as  also 
small  tubercles  on  the  pleura  and  peritonseum.  We  often 
find  fluid  also  between  the  arachnoid  coat  and  the  pia  ma- 
ter ;  sometimes  effused  in  small  patches  between  these  two 
membranes,  and  at  others  over  a  large  extent ;  when  this 
anasarcous-like  effusion  takes  place,  the  vessels  of  the  pia 
mater  are  found  more  distended  with  blood  than  usual,  and 
the  arachnoid  membrane  is  thick  and  opaque  ;  in  most 
cases  where  this  effusion  takes  place,  water  is  also  secreted 
in  the  lateral  ventricles,  and  in  the  sheath  of  the  vertebral 
canal. 

There  is  some  difficulty  experienced  in  distinguishing 
inflammation  of  the  pia  mater  on  account  of  the  great  num- 
ber of  small  vessels  which  naturally  ramify  on  it ;  how- 
ever, in  the  inflamed  state  they  become  much  more  numer- 
ous, and  by  their  anastomoses,  make  a  beautiful  reticulated 
appearance,  not  however,  causing  such  a  general  redness 
as  may  be  observed  in  the  inflammation  of  some  other 
membranes ;  and  when  the  inflammation  runs  high,  pus  is 
formed,  which  is  effused  on  the  whole  upper  surface  of  the 
brain.  A  common  morbid  appearance  found  in  the  pia 
mater  is  the  formation  of  small  cysts,  containing  water, 
which  are  generally  called  hydatids ;  these  are  found  more 
usually  on  the  choroid  plexus,  and  in  the  velum  interposi- 
tum.  Inflammation  of  the  substance  of  the  brain  is  occasion- 
ally observed  arising  from  external  injury ;  the  redness, 
which  is  generally  slight,  is  confined  to  one  particular 
part;  in  this  state,  when  cut  into,  the  colour  appears  to 
arise  from  a  great  many  small  vessels  which  are  filled  with 
red  blood ;  the  inflamed  part  is  softer  and  more  yielding 
than  natural,  giving  rise  to  an  appearance  which  has  been 
lately  described  by  French  writers,  and  called  "ramollis- 
sement ;"  when  the  inflammation  proceeds  further,  abscess- 
es holding  pus  are  formed,  which,  if  of  a  large  size,  break 
down  the  substance  of  the  brain,  and  present  a  very  jagged 
appearance  on  their  internal  surface.  Apoplexy,  or  an  ef- 
fusion of  blood  or  serum  either  on  the  surface  or  in  the 
substance  of  the  brain,  is  also  to  be  met  with,  and  occa- 
sionally into  some  of  the  ventricles ;  the  blood  found  in 
those  situations  is  almost  always  black  and  coagulated,  the 
substance  of  the  brain  is  torn ;  when  the  person  survives 
the  attack,  and  recovers  the  energy  of  the  organ,  the  blood 
becomes  absorbed  in  part,  a  regular  cyst  or  cell  encloses 
the  remainder,  and  in  some  cases  no  trace  remains  of  the 
original  disease,  except  some  condensed  or  cicatrized  ap- 
pearance. Deposition  of  caseous  and  even  of  earthy  matter 


DUBLIN    DISSECTOR.  317 

in  the  arteries  of  the  brain  may  also  be  looked  for ;  this 
appearance  is  by  no  means  rare,  particularly  in  old  sub- 
jects ;  arising  from  this  state  of  the  arteries,  aneurisms  of 
the  internal  carotids  are  described  by  some  authors,  but 
they  are  not  of  common  cccurrence. 


CHAPTER  III. 

DISSECTION  OF  THE  NERVES. 

THE  course  and  ultimate  distribution  of  most  of  the 
nerves  have  been  already  mentioned  in  the  description  of 
the  muscles  and  of  the  several  regions  of  the  body ;  in  the 
present  chapter  they  shall  be  considered  in  a  systematic 
manner,  commencing  with  the  cerebral  nerves,  the  origins 
of  which  have  been  already  described. 


SECTION  I. 

DISSECTION    OF    THE    CEREBRAL    NERVE8. 

1.  OLFACTORY  nerves;  from  the  bulb,  which  each  of 
these  nerves  forms  at  the  side  of  the  crista  galli,  several 
branches  descend  into  the  nose,  through  the  foramina,  in 
the  cribriform  plate;  they  may  be  divided  into  the  inter- 
nal, middle,  and  external.  The  internal  branches,  about  ten 
in  number,  descend  in  grooves  along  the  septum,  subdivide 
into  many  filaments  which  form  a  plexus  with  each  other 
in  the  mucous  membrane ;  some  of  these  can  be  traced 
nearly  to  the  floor  of  the  nose.  The  middle  branches  are 
distributed  to  the  mucous  membrane  lining  the  roof  of  each 
nostril.  The  'external  branches  descend  along  the  grooves 
on  the  turbinated  bones,  dividing  and  communicating  fre- 
quently with  each  other,  so  as  to  form  numerous  plexuses, 
which  are  lost  in  the  pituitary  membrane.  All  the  branch- 
es of  the  olfactory  nerves  are  very  soft  in  the  cranium,  but 
in  passing  through  the  ethmoid  bone  they  each  receive  a 
sheath  from  the  dura  mater,  which  is  ultimately  lost  in  the 
external  layer  of  the  mucous  membrane. — (See  the  Ana- 
tomy of  the  Nose.) 

27* 


318  DUBLIN    DISSECTOR. 

II.  OPTIC  NERVES  ;  each  optic  nerve  on  passing  through 
the  optic  foramen,  becomes  surrounded  by  a  strong  sheath, 
derived  from  the  dura  mater ;  the  four  rectt  muscles  next 
surround  it,  from  the  fleshy  portions  of  which  it  is  separa- 
ted by  a  considerable  quantity  of  soft  fat,  in  which  several 
nerves  and  vessels  are  lodged  ;  from  the  optic  foramen  this 
nerve  proceeds  forwards  and  a  little  inwards,  so  as  to  be 
slightly  curved,  the  convexity  outwards ;  at  the  back  part 
of  the  eye  it  is  very  much  constricted ;  it  then  pierces  the 
sclerotic  and  choroid  membranes  and  terminates  in  the 
retina.— (See  Anatomy  of  the  Eye.)  The  ophthalmic  ar- 
tery accompanies  this  nerve,  in  the  optic  foramen  it  lies 
beneath  it,  it  afterwards  twines  around  it  to  its  internal 
side. 

[This  artery  gives  off  the  central  artery  of  the  retina,  which  perfo- 
rates the  sheath  of  the  nerve,  and  gets  into  the  substance  of  the  nerve, 
with  which  it  passes  to  the  ball  of  the  eye  to  be  variously  distributed.] 

In  addition  to  the  dura  mater,  this  nerve  possesses  a  very 
dense  neurilema  which  sends  in  numerous  processes  to  form 
small  canals  or  tubes  in  which  the  nervous  substance  is 
contained,  so  that  this  nerve  is  not  composed  like  other 
nerves,  of  several  filaments  placed  parallel  to  each  other  ; 
if  the  white  substance  be  removed  by  maceration  in  an 
alkali,  its  cellular  structure  will  become  obvious. 

At  the  side  of  the  body  of  the  sphenoid  bone,  the  follow- 
ing four  nerves  of  the  orbit  lie  according  to  their  numeri- 
cal order,  viz.  most  superiorly  the  third  pair,  then  the 
fourth,  next  the  ophthalmic  branch  of  the  fifth  pair,  and 
most  inferiorly  the  sixth  or  abducens  nerve ;  they  are  here 
closely  united  to  each  other,  forming  what  may  be  termed 
the  orbital  plexus,  until  they  arrive  at  the  anterior  clinoid 
process,  where  they  separate,  and  as  they  are  entering  the 
foramen  lacerum  orbitale  they  lie  thus ;  most  superior  is 
the  fourth,  then  the  frontal  branch  of  the  ophthalmic,  next 
the  superior  division  of  the  third,  external  to  which,  and 
near  to  the  outer  wall  of  the  orbit,  is  the  lachrymal  nerve 
of  the  ophthalmic,  after  these  the  nasal  nerve,  below  which 
is  the  inferior  division  of  the  third,  and  lastly,  lying  infe- 
rior to  them  all,  holding  the  same  relation  to  them  as  at  the 
cavernous  sinus,  is  the  sixth  nerve;  to  this  last  the  ascend- 
ing branches  of  the  superior  cervical  ganglion  of  the  sym- 
pathetic nerve  are  intimately  connected,  and  several  fila- 
ments from  these  can  be  traced  into  the  orbital  plexus. 

To  expose  these  four  nerves  the  orbit  should  be  opened, 
which  is  to  be  done  by  dividing  the  orbital  plate  of  the  os 
frontis  by  two  cuts  with  the  saw,  these  should  unite  in  the 
optic  foramen;  the  internal  is  to  be  carried  forward  to  the 


DUBLIN    DISSECTOR.  319 

superciliary  arch  about  half  an  inch  external  to  the  inter- 
nal angular  process ;  the  external  incision  is  to  be  carried 
deeply  through  the  malar  bone;  a  slight  blow  with  the 
hammer  will  then  throw  fowards  the  roof  of  the  orbit,  and 
the  bone  will  separate  easily  from  the  periosteum. 

III.  The  THIRD  PAIR,  or  motores  oculorum,  in  passing 
through  the   foramen   lacerum  orbitale,  divide   into  two 
branches,  a  superior  and  inferior ;  the  superior,  or  the  small- 
er, passes  between  the  heads  of  the  external  rectus  muscle 
and  over  the  optic  and  nasal  nerves,  and  divides  into  two 
branches,  the  smaller  and  shorter  one  of  which  supplies 
the  superior  rectus,  the  other  the  levator  palpebrse  muscle. 
The  inferior  or  the  larger  branch  passes  below  and  to  the 
outside  of  the  optic  nerve,  and  divides  into  three  branches, 
an  internal,  middle,  and  external ;  the  internal  is  the  lar- 
gest, it   passes  obliquely   downwards,  forwards,  and   in- 
wards, beneath  the  optic  nerve,  and  getting  to  its  internal 
side  is  distributed  to  the  internal  rectus,  the  middle  to  the 
inferior  rectus ;  and  the  external,  which  is  the  longest,  pass- 
es downwards  and  forwards  on  the  surface  of  the  inferior 
rectus,  between  it  and  the  globe  of  the  eye,  (it  gives  no  fil- 
aments to  this  muscle,)  and  is  lost  in  the  inferior  oblique 
muscle ;  this  last  branch  gives  off  from  its  root  a  small 
short  filament  to  the  ophthalmic  ganglion.   All  the  branches 
of  the  third  pair  are  distributed  to  the  ocular  surfaces  of  the 
five  muscles  they  supply. 

IV.  The  TROCHLEATOR,  or  fourth  nerve,  having  entered 
the  orbit  by  the  foramen  lacerum,  ascends  obliquely  for- 
wards and  inwards  above  the  levator  palpebrre  and  the 
superior  rectus,  and   is   distributed   by  four  or  five  fine 
branches  to  the  upper  or  orbital  surface  of  the  superior 
oblique  muscle  :  as  this  delicate  nerve  is  passing  along  the 
outer  side  of  the  cavernous  sinus,  it  lies  between  the  third 
pair  and  the  ophthalmic  branch  of  the  fifth,  below  the  for- 
mer and  above  the  latter  and  the  sixth;  as  it  enters  the 
orbit  it  mounts  above  the  third  and  fifth,  a  fine  filament 
usually  connects  it  to  the  latter,  it  is  then  the  highest  nerve 
in  the  orbit,  both  it  and  the  frontal  being  immediately  be- 
neath  the  periosteum ;    previous  to  entering  the  oblique 
muscle  its  size  is  somewhat  increased. 

V.  THE  TRIGEMINI,  or  the  fifth  pair,  having  formed  the 
semilunar  or  Casserian  ganglion,  divides  into  three,  the 
ophthalmic,  the  superior  and  inferior  maxillary  nerves. 

The  OPHTHALMIC  NERVE  passes  along  the  outer  side  of 
the  cavernous  sinus  below  the  third  and  fourth,  and  above 
the  sixth  ;  in  this  situation  it  receives  some  filaments  from 
the  sympathetic  nerve  ;  as  it  approaches  the  foramen  lace- 
rum orbitale,  it  divides  into  three  branches,  the  lachrymal, 


320  DUBLIN    DISSECTOR. 

frontal,  and  nasal,  which  are  situated  with  respect  to  the 
other  nerves  as  above  described. 

The  lachrymal  nerve,  the  smallest  and  most  external  of  the 
three,  passes  forwards  and  outwards  to  the  lachrymal  gland 
above  the  external  rectus  muscle,  and  beneath  the  perios- 
teum, but  gives  no  branches  to  this  muscle  ;  it  is  surround- 
ed by  fat  and  accompanied  by  the  lachrymal  artery  ;  it 
sends  off,  in  this  course,  two  small  branches,  one  through 
the  spheno-maxillary  fissure  to  communicate  with  the  su- 
perior maxillary  nerve,  and  the  other  through  the  malar 
bone,  to  communicate  with  the  facial  nerve ;  near  the 
gland  the  lachrymal  nerve  enlarges  and  sends  four  or  five 
branches  to  its  inferior  surface,  and  it  then  terminates  in 
several  fine  soft  filaments  on  the  conjunctiva,  lining  the 
superior  palpebra  and  cellular  membrane  between  the 
gland  and  malar  bone. 

The  frontal  nerve  enters  the  orbit,  between  the  superior 
rectus  and  the  periosteum,  along  with  the  fourth  but  infe- 
rior and  external  to  it ;  it  passes  forwards  in  a  kind  of 
groove  on  the  upper  surface  of  the  levator  palpebrse  mus- 
cle ;  and  near  the  superciliary  arch  it  divides  into  two 
branches,  an  internal  and  external ;  the  internal  or  supra- 
trochleator  nerve,  the  smaller  branch,  runs  forwards  and  in- 
wards above  the  trochlea  of  the  superior  oblique  muscle, 
and  is  distributed  to  the  corrugator  supercilii,  orbicularis 
palpebrarum,andoccipito-frontalis  muscles,  also  to  the  in- 
teguments of  the  forehead  and  superior  eyelid  ;  it  commu- 
nicates with  the  infra-trochleator  branch  of  the  nasal  nerve, 
and  sends  one  or  two  small  filaments  into  the  frontal  sinus. 
The  external  branch,  or  the  supra-orbital  or  proper  frontal 
nerve,  appears  as  the  continuation  of  the  original  trunk, 
both  in  size  and  in  direction,  it  passes  through  the  super- 
ciliary notch  or  foramen,  ascends  on  the  forehead  divides 
into  two  branches  which  subdivide  into  numerous  fila- 
ments, these  chiefly  ascend  in  the  muscles  and  integuments 
of  the  scalp,  many  of  them  take  a  very  long  course,  and 
communicate  with  the  portio  dura,  with  the  occipital  nerves, 
and  with  those  from  the  opposite  side.  Neither  the  frontal 
nor  lachrymal  nerve  gives  any  motor  filaments  to  the  mus- 
cles in  the  orbit. 

The  nasal  nerve  separates  from  the  frontal  behind  the  or- 
bit, enters  this  cavity  beneath  that  branch,  and  between  the 
two  heads  of  the  external  rectus,  it  then  runs  obliquely  for- 
wards and  inwards  above  the  optic  nerve  and  below  the  su- 
perior rectus  muscle,  and  continues  its  course  along  the 
inner  side  of  the  orbit  below  the  superior  oblique  muscle, 
and  here  divides  into  two  branches,  the  external  or  the  in- 
fra-trochleator nerve,  and  the  internal  or  the  nasal ;  the 


DUBLIN    DISSECTOR.  321 

nasal  nerve,  previous  to  its  entrance  into  the  orbit,  is  joined 
by  a  filament  from  the  sympathetic  nerve ;  on  the  outer 
side  of  the  optic,  and  just  as  it  enters  this  cavity,  it  gives 
off  a  delicate  branch  about  an  inch  in  length,  which  runs 
along  the  outer  side  of  the  optic  nerve  to  the  lenticular 
ganglion  ;  as  the  nasal  nerve  passes  over  the  optic  it  gives 
off  two  ciliary  nerves.  The  infra-trochleator  nerve  runs  for- 
wards beneath  the  pulley  of  the  oblique  muscle,  and  di- 
vides into  several  filaments  which  communicate  with  the 
supra-trochleator  nerve,  arid  are  distributed  to  the  lachry- 
mal passages,  and  to  the  integuments  and  muscles  on  the 
side  and  dorsum  of  the  nose.  The  internal  branch  or  the 
proper  nasal  passes  through  the  anterior  of  the  internal  or- 
bital holes  into  the  cranium,  crosses  the  cribriform  plate, 
and  descends  by  the  side  of  the  crista  galli  into  the  nasal 
fossa3  where  it  divides  into  posterior  and  anterior  filaments  ; 
the  former  are  distributed  to  the  septum,  the  latter  descend 
behind  the  nasal  bones,  and  are  lost  in  the  integuments  at 
the  tip  of  the  nose.  The  sixth  pair  of  nerves  should  be 
next  dissected,  as  it  is  distributed  along  with  the  preceding 
nerves  in  the  orbit. 

SIXTH  or  ABDUCENS  NERVE,  after  traversing  the  cavernous 
sinus  (where  it  is  joined  by  branches  from  the  sympathetic 
nerve)  on  the  outer  side  of  the  carotid  artery,  enters  the 
orbit  through  the  lower  part  of  the  foramen  lacerum  be- 
tween the  origins  of  the  external  rectus,  beneath  the  other 
orbital  nerves  and  above  the  ophthalmic  vein  ;  it  then  passes 
forwards  and  outwards,  and  is  distributed  to  the  ocular  sur- 
face of  the  external  rectus  muscle.  All  the  motor  nerves 
in  the  orbit  are  distributed  to  the  same  surface  of  their  re- 
spective muscles,  except  the  fourth,  which  spreads  its 
branches  on  the  orbital  surface  of  the  superior  oblique 
muscle. 

The  student  should  next  examine  the  lenticular  or  ophthal- 
mic ganglion ;  this  small  body  is  situated  near  the  back  part 
of  the  orbit  between  the  optic  nerve  and  the  external  rec- 
tus muscle ;  it  is  of  a  reddish  colour  and  surrounded  by 
soft  fat ;  its  posterior  superior  angle  receives  the  filament 
before  mentioned  from  the  nasal  branch  of  the  ophthalmic, 
and  its  posterior  inferior  angle  receives  the  twig  from  the 
inferior  oblique  branch  of  the  third  pair ;  these  two  nerves 
are  described  by  some  as  forming  this  ganglion  ;  from  the 
anterior  angles  of  this  ganglion  two  fasciculi  of  fine  nerves 
proceed,  termed  the  ciliary,  the  inferior  fasciculus  is  larger 
than  the  superior.  The  ciliary  nerves  are  about  twenty  in 
number,  eight  or  ten  in  the  inferior  fasciculus,  about  six  in 
the  superior,  and  three  or  four  internally,  which  arise  from 
the  nasal  nerve  ;  the  ciliary  nerves  twine  along  the  surface 


322  DUBLIN    DISSECTOR. 

of  the  optic  nerve,  accompanied  by  the  ciliary  arteries,  and 
pierce  the  back  part  of  the  sclerotic  coat,  they  then  be- 
come flat,  and  proceed  forwards  in  parallel  grooves  on  the 
inner  surface  of  that  membrane,  with  very  little  connexion 
to  the  choroid  coat ;  at  the  anterior  part  of  the  eye  they 
meet  the  ciliary  ligament,  in  this  substance  most  of  these 
nerves  are  lost,  hence  some  consider  this  as  a  ganglion  ;  on 
each  side,  however,  one  or  two  branches  may  be  traced 
through  this  into  the  iris,  in  which  they  divide  into  numer- 
ous filaments  of  extreme  minuteness. 

The  several  nerves  of  the  orbit  have  different  offices  to 
discharge  ;  no  less  than  seven  nerves  are  engaged  in  the  op- 
tic  apparatus,  viz.  the  second,  third,  fourth,  sixth,  and  por- 
tions of  the  fifth,  seventh,  and  sympathetic  ;  the  respective 
office  of  each  of  these  is  probably  as  follows : — the  second 
is  a  sentient  nerve,  the  seat  of  vision ;  the  third,  fourth, 
aud  sixth  supply  the  orbital  muscles  with  their  voluntary 
or  motor  power ;  branches  of  the  seventh  also  impart  the 
same  to  the  sphincter  oculi  or  orbicularis  palpebrarurn ; 
the  ophthalmic  portion  of  tne  fifth  endows  with  sensation 
all  the  parts  within  the  orbit,  also  the  interior  of  the  eye, 
the  surface  of  the  globe,  the  palpebraB,  the  lachrymal  ap- 
paratus, the  integuments  of  the  forehead,  &c.  &c.  The 
filaments  of  the  sympathetic  nerve  serve  to  connect  more 
closely  the  component  parts  of  the  orbital  plexus  with  each 
other,  and  with  the  system  at  large,  they  also  probably 
serve  some  useful  purpose  in  reference  to  the  ophthalmic 
ganglion,  to  which  they  are  connected  through  the  nasal 
nerve,  the  sympathetic  being  directly  connected  to  or  en- 
gaged in  most  of  the  principal  ganglions  in  the  body.  The 
lenticular  or  ophthalmic  ganglion  also  is  interesting  as  to 
its  connexions,  as  it  in  this  respect  resembles  the  ganglions 
on  the  spinal  nerves ;  thus,  it  has  two  roots,  the  third  pair 
supplies  the  motor,  while  the  nasal  filament  of  the  fifth 
which  also  carries  the  sympathetic  connexion,  imparts  the 
sensitive  quality  ;  the  distribution  also  of  the  branches  of 
this  ganglion  is  in  accordance  with  its  component  elements, 
inasmuch  as  they  are  distributed  to  one  of  the  most  deli- 
cately sensible,  and  one  of  the  most  active  structures  in  the 
whole  range  of  the  animal  economy,  namely  the  iris,  the 
muscular  nature  of  which  too  may  be  inferred  from  the 
very  circumstance  of  this  peculiar  nervous  supply. 

The  student  should  next  proceed  to  examine  the  superior 
and  inferior  maxillary  nerves,  the  remaining  divisions  of 
the  fifth  pair.  Remove  the  outer  wall  of  the  orbit  with  the 
saw  or  hammer,  make  a  vertical  section  of  the  nose  and 
face,  and  separate  the  globe  of  the  eye  and  its  muscles 


DUBLIN    DISSECTOR.  323 

from  their  attachments ;  below  the  cavity  of  the  orbit  the 
superior  maxillary  nerve  may  be  seen. 

The  SUPERIOR  MAXILLARY  NERVE  passes  from  the  middle 
of  the  Casserian  ganglion  forwards  through  the  foramen 
rotundum  into  the  pterygo-maxillary  fossa ;  it  here  sends 
off  several  branches,  and  then  passing  through  the  spheno- 
maxillary  fissure  it  continues  its  course  forwards  along  the 
infra-orbital  canal  to  the  cheek,  where  it  terminates  in  the 
infra-orbital  nerves  ;  in  the  pterygo-maxillary  fossa  it  first 
sends  down  two  small  branches  along  the  back  part  of  the 
superior  maxillary  bone;  these,  after  a  short  course,  unite 
in  a  small  triangular  reddish  substance  called  the  splieno- 
palatine  ganglion,  or  the  ganglion  of  Meckel ;  this  ganglion  is 
imbedded  in  fat,  surrounded  by  the  branches  of  the  internal 
maxillary  artery,  and  is  situated  on  the  external  side  of  the 
nasal  plate  of  the  palate  bone,  which  separates  it  from  the 
cavity  of  the  nose,  behind  the  tuberosity  of  the  superior 
maxillary  bone,  and  in  front  of  the  pterygoid  processes. 
Three  sets  of  branches  proceed  from  this  ganglion,  an  infe- 
rior, internal,  and  posterior.  First  the  inferior  or  the  palatine 
nerves  descend  in  the  bony  canal  of  that  name,  send  some 
small  twigs  through  this  canal  to  the  spongy  bones,  and 
near  the  palate  separate  into  three  filaments,  an  anterior, 
middle,  and  posterior ;  the  anterior  passes  forwards  in  a 
groove  within  the  alveoli  and  above  the  mucous  membrane, 
supplying  the  latter  and  sending  small  branches  into  the 
bone  to  the  teeth  :  the  middle  and  posterior  filaments  of  the 
palatine  nerve  are  distributed  to  the  amygdalae,  the  soft 
palate,  and  the  uvula.  The  internal  branch,  or  the  spheno- 
palatine  nerve  is  very  short,  passes  through  the  spheno- 
palatine  hole  into  the  upper  and  back  part  of  the  nose,  and 
divides  into  five  or  six  branches;  the  most  of  these  pass  im- 
mediately into  the  mucous  membrane,  covering  the  supe- 
rior and  middle  spongy  bones,  one  branch  called  the  naso- 
palatine  nerve,  or  nerve  of  Cotunnius,  passes  beneath  the  sphe- 
rioidal  sinus,  and  descends  obliquely  forwards  along  the 
septum  nasi  as  far  as  the  foramen  incisivum,  where  it  com- 
municates with  the  anterior  palatine  branches,  and  where 
some  anatomists  describe  a  small  ganglion  (naso-palatine) 
to  exist ;  this,  however,  in  the  human  subject,  can  seldom 
be  distinguished  from  the  surrounding  fat  and  vessels. 
The  third  or  the  posterior  branch  of  MeckeFs  ganglion  is 
the  Vidian  nerve ;  this  passes  backwards  through  the  Vi- 
dian  canal  above  the  internal  pterygoid  plate,  and  sends 
some  small  filaments  into  the  sphenoidal  sinus  ;  it  then 
perforates  the  cartilaginous  substance  that  closes  the  fora- 
men lacerum  anterius,  enters  the  cranium,  and  divides  into 
two  branches,  an  inferior  and  superior ;  the  inferior  or  ca- 


324  DUBLIN    DISSECTOR. 

rotid  branch  enters  the  cavernous  sinus,  and  joins  the 
plexus  formed  in  this  sinus  around  the  artery  by  the  as- 
cending branches  of  the  superior  cervical  ganglion  of  the 
sympathetic;  the  superior  branch  runs  backwards  and  out- 
wards beneath  the  dura  mater  and  Casserian  ganglion  in  a 
groove  on  the  petrous  bone,  enters  the  hiatus  Fallopii  in 
this  bone,  and  becomes  attached  to  the  portio  dura  nerve, 
which  it  accompanies  as  far  as  the  back  part  of  the  tym- 
panum ;  the  Vidian  nerve  then  leaves  the  portio  dura,  re- 
ceives the  name  of  corda  tympani,  and  enters  the  typanum 
a  little  below  the  pyramid  ;  it  now  proceeds  forwards  be- 
tween the  long  leg  of  the  incus  and  the  handle  of  the  mal- 
leus, to  the  latter  it  is  firmly  connected  ;  it  then  escapes  by 
the  hole  in  the  glenoid  fissure  along  with  the  tendon  of  the 
laxator  tympani  muscle  ;  it  next  runs  downwards,  inwards, 
and  forwards,  joins  the  gustatory  nerve,  and  continues  at- 
tached to  it  as  far  as  the  submaxillary  gland ;  it  now  leaves 
the  gustatory  nerve  and  unites  with  some  filaments  from  it 
in  the  submaxillary  ganglion,  which  is  situated  near  the  pos- 
terior edge  of  the  submaxillary  gland,  and  from  which  a 
number  of  filaments  proceed ;  these  form  a  plexus  which 
supplies  this  gland.  As  this  Vidian  or  recurrent  nerve 
takes  this  singularly  intricate  course,  it  goes  under  differ- 
ent denominations,  and  serves  to  maintain  several  interest- 
ing communications ;  for  example,  it  connects  the  cervical 
ganglions  of  the  sympathetic  nerve  with  the  spheno-pala- 
tine,  also  the  latter  with  the  submaxiliary  ganglion,  it  also 
joins  the  superior  and  inferior  maxillary  nerves  to  one  an- 
other and  both  to  the  portio  dura  ;  the  nervous  supply  to 
the  muscles  of  the  palate  also  is  thus  connected  to  the  por- 
tio dura,  the  great  muscular  nerve  of  the  face,  &c. 

The  superior  maxillary  nerve  immediately  after,  and 
sometimes  previous  to  giving  off  the  two  descending 
branches  which  join  the  spheno-palatine  ganglion,  sends 
off  the  orbital  branch,  this  ascends  through  the  spheno-max- 
illary  fissure  and  divides  into  two  branches,  the  malar  and 
temporal;  the  malar  communicates  with  the  lachrymal 
nerve,  passes  through  a  small  canal  in  the  malar  bone,  and 
is  distributed  to  the  integuments  and  muscles  covering  the 
malar  bone  ;  the  temporal  branch  also  passes  through  the 
malar  bone  into  the  temporal  fossa,  pierces  the  temporal 
fascia,  becomes  cutaneous,  and  joining  some  branches  of 
the  facial  nerve,  it  accompanies  the  temporal  artery,  and 
is  lost  in  the  integuments  of  the  temple  and  head.  The  su- 
perior maxillary  nerve  next  gives  off  the  posterior  dental 
nerves ;  these  are  two  or  three  branches  which  wind  round 
the  tu berosity  of  the  maxillary  bone,  enter  small  foramina, 
which  lead  to  the  posterior  alveoli  in  this  bone,  and  supply 


DUBLIN    DISSECTOR.  325 

the  molar  teeth  ;  some  branches  also  supply  the  gums  and 
the  buccinator  muscle.  As  the  infra-orbital  nerve,  which  is 
the  last  branch  of  the  superior  maxillary,  proceeds  along 
the  floor  of  the  orbit,  it  sends  off'  some  small  filaments  to 
the  fat  and  muscles  in  this  region,  also  the  anterior-dental ; 
this  descends  along  the  fore  part  of  the  antrum,  to  the 
lining  membrane  of  which  it  gives  some  fine  filaments  and 
is  then  lost  in  several  branches  which  supply  the  canine 
and  incisor  teeth :  the  infra-orbital  nerve  then  escapes 
through  the  foramen  of  the  same  name,  beneath  the  orbi- 
cularis  palpebrarum  and  levator  labii  superioris  alseque 
nasi  muscles ;  it  here  divides  into  several  branches  which 
are  distributed  to  the  face,  some  of  these  ascend  to  the  pal- 
pebrse,  others  pass  outwards  to  the  cheek,  and  the  largest 
branches  descend  to  the  ala  nasi  and  to  the  upper  lip ; 
these  different  branches  have  frequent  communications  on 
the  side  of  the  face  with  the  portio  dura,  on  the  nose  with 
the  nasal  nerves,  and  on  the  buccinator  muscle  they  form 
a  plexus  with  each  other  and  with  the  buccal  and  facial 
nerves. 

The  INFEKIOR  MAXILLARY  NERVE  ;  this,  which  is  the  third 
and  largest  branch  of  the  fifth  pair,  immediately  passes 
from  the  ganglion  through  the  foramen  ovale  into  the  zygo- 
matic  fossa  behind  the  external  pterygoid  muscle,  where  it 
divides  into  two  large  branches,  a  superior  or  external,  and 
an  inferior  or  internal.  The  inferior  maxillary  nerve  con- 
sists of  two  portions,  one  is  plexiforrn  and  sensitive,  and 
proceeds  from  the  Casserian  ganglion,  the  other  is  conceal- 
ed by  this,  and  consists  of  white  parallel  fibres  which  do 
not  pass  through  the  ganglion ;  this  is  the  motor  portion 
of  this  nerve  ;  in  the  zygomatic  fossa  this  small  deep  por- 
tion winds  round  the  other,  becomes  anterior  to  it,  and  both 
unite  inseparably  ;  the  nerve  then  divides  into  two  branches, 
superior  and  inferior.  The  superior  or  external  retains  the 
motor  portion  of  the  trunk,  and  immediately  subdivides 
into  four  set  of  branches,  viz.  the  deep  temporal,  massete- 
ric,  buccal,  and  pterygoid  ;  the  inferior  or  internal  division 
of  the  nerve  is  the  larger,  and  subdivides  into  the  auricu- 
lar, inferior  dental,  and  gustatory  nerves,  which  are  pro- 
bably all  nerves  of  sensation.  First,  the  deep  temporal  nerves 
are  two  in  number,  an  anterior  and  posterior,  they  ascend 
between  the  temporal  bone  and  muscle,  and  are  lost  in  the 
latter ;  some  small  branches  escape  through  the  temporal 
fascia  and  communicate  with  the  cutaneous  temporal 
nerves.  Second,  the  Buccal  nerve  arises  in  general  in  com- 
mon with  one  of  the  last,  it  passes  forwards  and  down- 
wards between  the  pterygoid  muscles,  to  the  external  of 
which,  and  to  the  temporal,  it  sends  some  branches,  it  then 
28 


326  DUBLIN    DISSECTOR. 

passes  between  the  coronoid  process  and  the  buccinator  mus- 
cle, and  on  the  latter  it  divides  into  several  long  branches 
which  form  a  plexus  on  this  muscle  with  branches  of  the  fa- 
cial and  infra-orbital  nerves.  Third,  the  masseleric  branch 
descends  obliquely  backwards  and  outwards  through  the 
sigmoid  notch  of  the  inferior  maxilla,  between  the  tempo- 
ral muscle  and  the  neck  of  the  lower  jaw,  close  to  the  lat- 
ter, to  which  also  it  sends  some  filaments ;  it  is  lost  in  the 
substance  of  the  masseter  muscle.  Fourth,  the  pterygoid 
branches  are  two  or  three  delicate  branches,  which  descend 
to  the  pterygoid  muscles.  Thus  the  muscular  portion  of 
the  trunk  of  the  inferior  maxillary  nerve  can  be  traced 
into  those  muscular  branches,  which  supply  the  live  great 
muscles  of  mastication  on  each  side. 

The  inferior  division  of  this  nerve  divides  into  three 
branches,  viz.  the  auricular,  dental,  and  lingual  or  gusta- 
tory nerves  ;  first,  the  auricular  or  temporo-auricular  branch  ; 
this  passes  backwards  and  outwards  behind  the  neck  of 
the  lower  jaw,  and  before  the  meatus  auditorius ;  it  here 
communicates  with  the  facial  nerve,  and  sends  small  fila- 
ments to  the  meatus  and  to  the  cartilages  of  the  ear,  also 
to  the  articulation  of  the  lower  jaw  ;  it  then  ascends  through 
the  parotid  gland  over  the  zygoma  and  divides  into  an  an- 
terior and  posterior  branch  which  follow  the  divisions  of 
the  temporal  artery,  communicate  with  the  facial  nerve, 
and  are  lost  in  the  integuments  on  the  anterior  and  lateral 
parts  of  the  head.  Second,  the  inferior  dental  nerve  sepa- 
rates from  the  gustatory,  and  is  connected  to  it  by  a  small 
twig,  it  then  descends  extern  il  to  it,  at  first  between  the 
two  pterygoid  muscles,  then  between  the  lower  jaw  and  the 
internal  pterygoid ;  it  is  here  separated  from  the  latter  by 
the  internal  lateral  ligament ;  about  the  middle  of  the  in- 
ternal surface  of  the  ramus  of  the  jaw  it  sends  off  a  small 
filament,  the  mylo-Jnpid  nej've,  this  descends  obliquely  for- 
wards, confined  in  a  groove  in  the  bone  by  an  expansion 
from  the  internal  lateral  ligament ;  near  the  chin  it  divides 
into  small  branches  from  the  mylo-hyoid,  genio-hyoid,  and 
digastric  muscles,  the  adjacent  cellular  tissue  and  lympha- 
tic glands.  The  dental  nerve  then  enters  the  canal  in  the 
lower  jaw,  which  extends  from  the  dental  foramen  oblique- 
ly forwards  beneath  the  teeth  as  far  as  the  chin ;  in  this 
course,  this  nerve,  which  is  .'tccompanied  by  the  dental 
vessels,  supplies  each  of  the  molar  and  canine  teeth  with 
soft  delicate  twigs,  and  at  the  mental  foramen  it  divides 
into  two  branches,  one  continues  its  course  within  the  bone 
beneath  the  incisor  teeth,  the  other  is  the  mental  nerve; 
this  escapes  by  the  mental  foramen,  bends  upwards,  and 
divides  in  a  radiated  manner  into  several  branches  which 


DUBLIN    DISSECTOR.  327 

pass  to  the  muscles,  mucous  membrane,  and  integuments 
of  the  lower  lip,  and  communicate  with  the  facial  nerve. 
Third,  the  lingual  or  gustatory  nerve  is  smaller  than  the 
dental,  to  which  it  is  connected  by  a  short  branch  which 
encloses  a  space  through  which  the  internal  maxillary  ar- 
tery passes;  beyond  this  branch  of  communication,  the 
corda  tympani  (which  has  been  before  traced  from  Meek- 
el's  ganglion)  joins  the  gustatory  nerve  at  an  acute  angle  ; 
the  latter  is  increased  in  size  at  this  spot ;  the  gustatory 
nerve  is  here  situated  between  the  external  pterygoid  and 
the  muscles  of  the  palate  and  pharynx ;  it  then  descends 
obliquely  forwards  between  the  internal  pterygoid  and  the 
ramusofthe  lower  jaw;  it  next  turns  forwards  above  the 
sub-maxillary  gland  and  the  mylo-hyoid  muscle,  and  lies 
on  the  mylo-hyoidean  attachment  of  the  superior  constric- 
tor of  the  pharynx,  and  on  the  mucous  membrane  of  the 
mouth  and  the  stylo-glossus  muscle,  and  accompanies  the 
Whartonian  duct;  it  then  ascends  above  the  sublingual 
gland,  and  becomes  attached  to  the  lateral  and  anterior 
parts  of  the  tongue.  In  this  arched  course  the  gustatory 
nerve  gives  off,  first,  one  or  two  small  filaments  to  the  in- 
ternal pterygoid  muscle ;  second,  several  to  the  tonsils,  to 
the  muscles  of  the  palate,  to  the  upper  part  of  the  pha- 
rynx, and  to  the  mucous  membrane  of  the  gums;  third, 
the  corda  tympani,  and  some  accompanying  filaments  to 
form  a  plexus  which  supplies  the  sub-maxillary  gland; 
fourth,  a  few  branches  which  descend  along  the  hyo-glos- 
sus  muscle  to  communicate  with  the  ninth  or  the  lingual 
nerve  ;  fifth,  a  fasciculus  of  nerves  to  the  sublingual  gland, 
and  to  the  surrounding  mucous  membrane  ;  lastly,  at  the 
tongue,  it  divides  into  several  branches,  some  pass  deep 
into  the  tissue  of  this  organ,  others  long,  fine  and  soft,  rise 
towards  its  surface,  and  are  lost  in  the  mucous  membrane 
and  in  the  small  conical  papillae  near  its  tip. 

The  SIXTH  PAIR  of  nerves  have  been  described  at  page 
321. 

VII.  FACIAL  NERVE  or  PORTIO  DURA  of  the  seventh  pair; 
as  this  nerve  is  passing  along  the  aqueduct  of  Fallopius  in 
the  temporal  bone  it  receives  superiorly  the  Vidian  nerve; 
at  the  back  part  of  the  tympanum  it  sends  off  that  nerve 
again,  which  then  receives  the  name  of  corda  tympani, 
here  it  also  sends  off  small  twigs  to  the  tensor  tympani  and 
stapedius  muscles  ;  as  it  escapes  by  the  stylo-mastoid  fora- 
men it  gives  off  three  branches,  the  posterior  auricular, 
stylo-hyoid,  and  sub-mastoid  ;  the  first,  or  the  posterior  auri- 
lar,  bends  upwards  and  backwards  behind  the  cartilage  of 
the  ear,  to  which  it  sends  several  long  branches,  others  also 
pass  backwards  to  the  integuments  covering  the  mastoid 


328  DUBLIN    DISSECTOR. 

process  and  occipital  bone ;  the  second,  or  the  stylo-Jiyoid 
nerve  is  distributed  to  the  digastric  and  styloid  muscles, 
and  anastomoses  with  the  sympathetic  and  glosso-pharyn- 
geal  nerves  ;  the  third,  or  the  sub-mastoid  branch  perforates 
the  posterior  belly  of  the  digastric,  supplies  it  with  several 
filaments,  and  then  communicates  with  the  glosso-pharyn- 
geal  nerve  around  the  jugular  vein  close  to  the  base  of  the 
cranium;  other  filaments  descend  and  join  the  laryngcal 
branches  of  the  pneumo-gastric  nerve.  The  facial  nerve 
then  turns  forwards  across  the  external  carotid  artery  and 
through  the  parotid  gland  ;  in  this  substance  it  divides  into 
two  large  branches,  the  superior  or  larger  is  called  tempo- 
ro-facial  ;  the  inferior,  which  is  smaller,  the  cervico-fu- 
cial;  these  two  branches  take  different  directions,  but  are 
still  connected  together  by  cross  branches  which  interlace 
with  each  other  in  a  plexiform  manner ;  this  plexus  is 
named  parotidean  plexus,  or  pes  anserinus.  The  temporo-fa- 
cial  nerve  ascends  obliquely  forwards  across  the  neck  of  the 
lower  jaw  ;  it  first  communicates  with  the  auricular  branch 
of  the  inferior  maxillary  nerve,  and  then  divides  into  three 
fasciculi,  the  temporal,  malar,  and  buccal ;  these  nerves 
take  that  course  which  their  name  implies ;  they  are  all  re- 
markable for  the  plexiform  arrangement  of  their  branches, 
and  for  their  frequent  communications  with  each  other, 
and  with  the  three  divisions  of  the  fifth  pair,  which  are 
distributed  to  the  face.  The  cermco-facial  nerve  descends 
obliquely  forwards  through  the  parotid  gland  towards  the 
angle  of  the  jaw,  where  it  is  only  covered  by  the  skin  and 
platysma ;  this  nerve  also  divides  into  many  branches, 
which  may  be  arranged  in  three  fasciculi,  the  maxillary,  the 
sub-maxillary,  and  the  cervical ;  the  first,  or  the  maxillary, 
cross  the  ramus  of  the  jaw  and  the  masseter  muscle,  and 
communicate  in  the  muscles  of  the  lower  lip  with  the  men- 
tal nerve,  and  with  the  superior  division  of  the  seventh ; 
the  second,  or  sub-maxillary,  course  along  the  base  of  the 
jaw,  sending  filaments  to  the  integuments  and  superficial 
muscles,  these  also  communicate  at  the  chin  with  the  men- 
tal nerve  ;  the  third,  or  cervical  branches,  are  very  long  and 
numerous  ;  they  are  distributed  to  the  platysma  and  to  the 
superficial  muscles  of  the  neck,  and  communicate  with 
several  filaments  of  the  cervical  plexus.  The  portio  dura 
nerve  has  been  ingeniously  but  erroneously  supposed  by 
Mr.  Bell  to  be  the  nerve  that  excites  the  muscles  of  the 
face  in  particular  conditions  of  respiration  and  in  the  ex- 
pression of  passion,  &c.,  hence  he  has  named  it  the  respi- 
ratory nerve  of  the  face ;  others  more  correctly  consider 
the  portio  dura  as  the  exclusive  motor  nerve  of  all  the  su- 
perficial muscles  of  the  face. 


DUBLIN    DISSECTOR.  329 

VIL  The  AUDITORY  NERVE  or  PORTIO  MOLLIS  of  the  seventh 
pair ;  this  simple  nerve  separates  from  the  portio  dura  at 
the  bottom  of  the  meatus  auditorius  internus,  and  then  di- 
vides into  two  branches,  an  anterior  and  posterior  ;  the  an- 
terior passes  forwards  to  the  cochlea,  penetrates  through 
many  small  openings,  and  is  distributed  to  the  membrane 
covering  its  spiral  lamina,  and  to  that  lining  the  canal  on 
its  axis:  the  posterior  branch  passes  outwards,  forms  a 
grey  swelling,  from  which  proceed  several  filaments  to 
supply  the  membrane  lining  the  vestibule  and  semi-circu- 
lar canals. — (See  Anatomy  of  the  Ear.) 

VIII.  GLOSSO-PHARYNGEAL  NERVE,  the  iirst  and  highest 
branch  of  the  eighth  pair  ;  this  small  and  most  probably  a 
compound  nerve,  passes  though  the  foramen  lacerum  pos- 
terius  by  a  distinct  canal,  it  then  passes  downwards  and 
forwards  anterior  and  internal  to  the  jugular  vein  and  in- 
ternal carotid  artery,  and  behind  the  stylo-pharyngeus  mus- 
cle ;  it  then  winds  round  this  muscle  to  its  forepart,  and 
descends  obliquely  inwards  between  it  and  the  stylo-glos- 
sus  to  the  posterior  and  lateral  parts  of  the  tongue ;  in  this 
course  this  nerve  forms  an  arch  nearly  parallel  to  that 
which  the  gustatory  and  lingual  nerves  describe  ;  the  glos- 
so-pharyngeal  is  smaller  than  either  of  these  nerves ;  it  is 
situated  between  them,  but  deeper  than  either;  and  has 
very  little  if  any,  communication  with  them.  As  this 
nerve  leaves  the  cranium  it  sends  one  or  two  small  twigs 
into  the  temporal  bone,  these  communicate  with  the  caro- 
tid plexus  in  the  cavernous  sinus ;  it  is  next  attached  to 
the  facial,  pneumo-gastric  and  sympathetic  nerves  by 
small  filaments,  which  arc  connected  together  by  loose  red- 
dish cellular  membrane,  and  entangled  with  several  small 
vessels.  This  nerve  next  gives  off  some  branches  to  the 
pharyngeal  plexus,  some  of  these  descend  along  the  neck, 
and  unite  with  the  sympathetic  and  cardiac  nerves,  others 
ascend  to  the  amygdala,  and  assist  in  forming  the  tonsillitic 
plexus  ;  as  it  approaches  the  pharynx,  this  nerve  gives 
several  branches  to  the  stylo-pharyngeus  and  hyo-glossus 
muscles,  also  the  superior  and  middle  constrictors  of  the 
pharynx  ;  several  filaments  pass  between  these  to  the  muco- 
us membrane  of  the  pharynx  and  fauces,  also  to  the  folds 
or  arches  of  the  palate,,  and  to  the  epiglottis;  the  remain- 
ing branches  of  the  glosso-p'haryngeal  nerve  are  distributed 
to  the  muscular  substance,  large  papillae,  and  mucous 
membrane  at  the  root  of  the  tongue  ;  the  lingual  branches 
are  considered  sentient,  the  muscular  or  pharyngeal  both 
sentient  and  motor. 

PNEUMO-GASTRIC  NERVE,  or  nervus  vagus;  this  large  com- 
pound  nerve  passes  through  the  foramen  lacerum  in  a 


330  DUBLIN    DISSECTOR. 

fibrous  canal  in  common  with  the  spinal  accessory,  but 
distinct  from  the  last  described  nerve,  and  anterior  to  the 
jugular  vein  ;  it  then  communicates  with  the  spinal  acces- 
sory, glosso-pharyngeal,  lingual,  facial,  sympathetic  and 
first  and  second  cervical  nerves  ;  to  all  these  it  is  closely 
connected,  and  the  nerve  here  has  the  compact  appearance, 
and  sometimes  the  greyish  tint  of  a  ganglion  ;  at  first  it  is 
placed  anterior  to  the  vein  and  to  the  lingual  nerve  ;  it  soon, 
however,  passes  behind  both  and  opposite  the  atlas,  the 
vein  separates  it  from  the  glosso-pharyngeal  nerve  which 
lies  anterior  to  that  vessel  ;  the  vagus  then  descends  along 
the  forepart  of  the  neck  enclosed  in  the  sheath  of  the  ca- 
rotid artery  and  jugular  vein  :  in  this  sheath  it  is  placed  be- 
tween these  vessels,  rather  behind  and  more  closely  con- 
nected to  the  vein  ;  on  the  right  side  this  nerve  enters  the 
thorax  between  the  subclavian  vein  and  artery,  crossing  the 
latter  at  right  angles ;  on  the  left  side  it  is  also  anterior 
but  nearly  parallel  to  the  subclavian  artery,  a  little  below 
which  it  crosses  obliquely  the  back  part  of  the  arch  of  the 
aorta ;  in  the  thorax  these  nerves  descend  at  first  obliquely 
backwards  behind  the  roots  of  the  lungs,  and  enter  the  pos- 
terior mediastinum,  they  then  descend  along  the  oesophagus 
through  the  diaphragm,  and  end  on  the  stomach.  The 
branches  of  each  may  be  divided  into  cervical,  thoracic, 
and  abdominal ;  the  cervical  branches  are,  the  pharyngeal, 
superior  laryngeal,  cardiac  and  recurrent  or  inferior  laryn- 
geal.  First,  the  pharyngeal  nerve  arises  from  the  vagus  near 
the  base  of  the  cranium,  and  soon  receives  a  twig  from  the 
spinal  accessory  ;  it  descends  obliquely  inwards  behind  the 
carotid  artery  to  the  side  of  the  pharynx,  divides  into  se- 
veral branches,  which  communicate  with  those  from  the 
glosso-pharyngeal,  superior  laryngeal,  and  sympathetic  ; 
all  these  branches  form  the  pharyngeal  plexus ;  this  plexus 
extends  along  the  side  of  the  middle  and  upper  constric- 
tors, and  sends  numerous  filaments  to  each  of  these  mus- 
cles, and  to  the  mucous  membrane  of  the  pharynx  and 
fauces.  Second,  the  superior  laryngeal  nerve  arises  a  little 
below  the  last ;  it  runs  in  an  arched  manner  downwards 
and  forwards  behind  the  internal  carotid  artery,  and  below 
the  superior  cervical  ganglion,  with  which  it  communicates, 
as  also  with  the  lingual  nerve;  it  sends  several  filaments 
to  the  pharyngeal  plexus,  and  then  divides  into  two  branch- 
es, external  and  internal ;  the  external  is  distributed  to  the 
sterno  and  hyo-thyroid,  and  to  the  other  superficial  mus- 
cles, also  to  "the  thyroid  body  and  to  the  cartilages  of  the 
larynx  ;  the  internal  perforates  the  thy  reo-hyoid  membrane 
and  divides  into  numerous  branches,  many  of  these  go  to 
the  anterior  surface  of  the  epiglottis,  to  the  glands  and  mu- 


DUBLIN    DISSECTOR.  331 

cous  membrane  connected  with  it,  also  to  the  arytenoid 
glands  and  muscles  ;  one  long  filament  descends  obliquely 
forwards  along  the  side  of  the  larynx,  beneath  the  thyroid 
cartilage,  and  supplies  the  crico-thyroid  muscle.  As  the 
vagus  descends  it  gives  off  tine  filaments  to  the  carotid  ar- 
tery, some  of  which  unite  with  the  sympathetic  and  with 
the  cervical  nerves ;  a  little  above  the  arteria  innorninata 
the  right  vagus  gives  off,  third,  cardiac  branches,  these,  two 
or  three  in  number,  join  the  cardiac  nerves  from  the  sym- 
pathetic ;  the  nerve  of  the  left  side  does  not  send  off  so  many 
or  such  large  branches  as  that  on  the  right  side  ;  on  the 
left  side  they  accompany  the  carotid  artery  to  the  arch  of 
the  aorta,  expand  over  it,  and  join  the  cardiac  plexus. 
Fourth,  the  inferior  laryngeal  nerve,  or  recurrent ;  that  on  the 
right  side  curves  round  the  subclavian  artery,  ascends  ob- 
liquely inwards  behind  the  carotid  and  inferior  thyroid  ar- 
tery, along  the  side  of  the  trachea  to  the  larynx ;  at  its 
origin  it  gives  off  some  cardiac  filaments,  afterwards  some 
branches  to  the  forepart  of  the  trachea  and  the  thyroid 
gland ;  it  then  supplies  the  lower  part  of  the  pharynx,  and 
ends  in  the  posterior  and  lateral  crico-arytenoid  and  in  the 
thyreo-arytenoid  muscles,  also  in  the  mucous  membrane  of 
the  larynx  on  which  it  communicates  with  the  superior 
laryngeal  nerve.  The  recurrent  nerve  on  the  left  side  is 
much  longer,  it  curves  round  the  arch  of  the  aorta  behind 
the  ligamentous  remains  of  the  ductus  arteriosus  ;  it  gives  off 
several  cardiac  and  pulmonary  branches,  and  then  ascends 
along  the  oesophagus  and  terminates  in  a  similar  manner 
to  that  on  the  right  side.  The  pneumo-gastric  nerves  in 
their  course  through  the  thorax,  pass  behind  the  roots  of  the 
lungs,  close  to  the  bronchi,  where  they  present  an  open 
plexiform  appearance,  and  send  off  the  pulmonary  and 
O3sophageal  nerves.  The  pulmonary  branches  arise  from 
each  vagus  a  little  above  the  root  of  each  lung  ;  a  few  of 
these  branches  pass  to  the  forepart  of  the  bronchial  tubes, 
and  form  there  a  small  plexus  termed  the  anterior  pulmonary 
plexus;  this  plexus  communicates  with  the  phrenic  nerve, 
and  sends  its  fine  filaments  along  the  pulmonary  vessels  to 
the  lungs  and  pericardium  ;  the  greater  number  of  these 
pulmonic  branches  pass  behind  the  bronchial  tubes  to  the 
posterior  pulmonic  plexus  ;  near  the  root  of  the  lung  each 
vagus  increases  in  size,  its  fibres  divide,  sub-divide,  and  re- 
unite in  an  areolar  or  plexiform  manner,  forming  the  poste- 
rior pulmonic  plexus;  this  plexus  is  very  large,  lymphatic 
ganglia  and  vessels  are  entangled  in  it,  and  several  branch- 
es from  the  sympathetic  join  it;  its  numerous  filaments  ac- 
company the  bronchial  tubes  closely  through  the  substance 
of  the  lungs.  Below  the  root  of  each  lung  the  fibres  of 


332  DUBLIN    DISSECTOR. 

each  vagus  again  approximate,  and  these  nerves  now  be- 
come attached  to  the  oesophagus,  along  which  they  descend 
to  the  stomach,  the  left  on  its  anterior,  the  right  (which  en- 
tered the  chest  on  a  plane  anterior  to  the  left)  on  its  poste- 
rior surface  ;  they  frequently  communicate  with  each  other 
so  as  to  encircle  the  oesophagus  with  a  sort  of  plexus, 
which  is  named  the  cesophageal  plexus,  or  plexus gula.  On 
the  stomach  the  right  vagus,  which  is  the  largest,  passes  be- 
hind the  cardiac  orifice,  to  which  it  sends  several  small 
branches  which  unite  with  some  from  the  left  or  anterior 
nerve;  these  form  the  cardiac  plexus  which  encircles  this 
part  of  the  stomach;  it  then  sends  many  long  filaments  to 
the  muscular  and  mucous  coats  of  the  stomach,  these  com- 
municate with  the  solar  plexus,  also  with  the  splenic,  hepa- 
tic and  renal.  The  left  or  anterior  vagus  spreads  its 
branches  along  the  anterior  surface  of  the  stomach  and  the 
lesser  curvature ;  several  of  these  pass  along  the  lesser 
omentum  to  the  liver. 

The  NERVUS  ACCESSORIUS,  or  the  third  branch  of  the 
eighth  pair;  this  nerve,  in  passing  through  the  foramen  la- 
cerum,  is  closely  connected  to  the  vagus ;  below  the  base 
of  the  cranium  it  communicates  with  the  eighth,  ninth,  and 
sympathetic  nerves,  passes  behind  the  internal  jugular 
vein,  perforates  the  upper  third  of  the  sterno-rnastoid  mus- 
cle, to  which  it  sends  some  filaments,  it  then  communicates 
freely  with  the  cervical  plexus,  is  increased  in  size,  and 
supplies  the  trapezius,  &c.  This  is  supposed  to  be  a  com- 
pound nerve. 

IX.  The  LINGUAL  NERVE,  or  the  ninth,  is  a  simple  nerve, 
on  escaping  from  the  condyloid  foramen  it  communicates 
with  the  eighth,  the  sympathetic,  and  the  nervous  arch  or 
loop  of  the  atlas ;  it  is  at  first  posterior  to  the  vessels  and 
nerves  in  this  situation,  it  then  descends  along  their  outer 
side,  soon  turns  forwards,  and  becomes  superficial  to  them  ; 
it  then  takes  the  arched  course  of  the  digastric  muscle 
across  the  neck,  parallel  but  superficial  to  the  lingual  ar- 
tery, and  arriving  at  the  side  of  the  base  of  the  tongue 
above  the  os  hyoides,  it  passes  above  the  mylo-hyoid  mus- 
cle and  lies  on  the  middle  constrictor  and  on  the  hyo-glos- 
sns,  at  the  anterior  edge  of  which  it  divides  into  several 
filaments;  some  of  these  plunge  :into  the  lingualis  and 
genio-glossus  muscles,  others  continue  on  to  the  point  of 
the  tongue,  communicating  with  each  other  and  supplying 
the  muscular  substance  of  this  organ.  As  the  lingual  nerve 
is  bending  across  the  neck  bdow  the  digastric  tendon,  it 
sends  off  a  considerable  branch,  thn  descendens  colli,  or  noni; 
this  nerve  frequently  receives  a  filament  from  the  pneumo- 
gastric  ;  it  descends  along  the  forepart  of  the  sheath  of  the 


DUBLIN    DISSECTOR  333 

carotid  artery ;  about  the  middle  of  the  neck  it  is  joined  by 
the  internal  descending  branches  of  the  cervical  plexus, 
with  which  it  forms  a  small  triangular  plexus,  the  branches 
of  which  pass  to  the  omo  and  sterno-hyoid  and  thyroid 
muscles;  on  the  latter  some  filaments  descend  into  the 
chest.  Near  the  os  hyoides  the  lingual  nerve  sends  some 
filaments  to  the  constrictors  of  the  pharynx  and  to  the 
stylo-pharyngeus,  also  one  to  the  thyreo-hyoid  muscle;  on 
the  surface  of  the  hyo-glossus  it  gives  off  several  branches 
to  the  surrounding  muscles,  some  also  to  communicate  with 
the  gustatory  branch  of  the  fifth  pair ;  the  lingual  nerve 
then  terminates  chiefly  in  the  genio-hyo-glossus  muscle, 
and  in  the  general  muscular  structure  of  the  tongue,  which 
organ  it  supplies  with  motor  power. 


SECTION  II. 


DISSECTION    OF    THE    SPINAL    NERVES. 


THERE  are  eight  CERVICAL  NERVES,  the  first  passes  out 
above  the  atlas,  and  is  named  the  sub-occipital,  the  eighth 
passes  out  above  the  first  dorsal  vertebra.  All  these  nerves 
immediately  outside  the  inter-vertebral  foramina,  divide  in- 
to a  posterior  and  an  anterior  branch  ;  the  posterior  of  each 
is  smaller  than  the  anterior,  with  the  exception  of  the  se- 
cond cervical  nerve,  whose  posterior  branch  is  very  con- 
siderable, as  it  not  only  supplies  the  adjacent  muscles,  but 
also  accompanies  the  occipital  artery  and  its  ramifications 
in  the  scalp  ;  the  posterior  branches  of  the  other  cervical 
nerves  are  small,  they  all  communicate  with  each  other, 
and  are  distributed  to  the  integuments  and  muscles  on  the 
back  part  of  the  neck.  The  anterior  branch  of  the  first,  or 
the  sub-occipital  passes  forwards  above  the  transverse  pro- 
cess of  the  atlas,  and  supplies  the  adjoining  small  recti  mus- 
cles, then  descends  before  the  atlas,  and  unites  with  the 
anterior  division  of  the  second  cervical,  so  as  to  encircle 
the  transverse  process  of  that  bone  with  a  nervous  loop ; 
in  this  course  the  sub-occipital  is  united  by  branches  to  the 
eighth  and  ninth,  and  to  the  superior  ganglion  of  the  sym- 
pathetic nerve ;  with  the  latter  nerve  the  anterior  branches 
of  all  the  spinal  nerves  regularly  communicate.  The  an- 
terior branch  of  the  second  having  received  that  from  the 
first,  descends  and  joins  the  anterior  division  of  the  third, 
this  in  like  manner  is  connected  to  the  fourth  ;  these  anas- 


334  DUBLIN    DISSECTOR. 

tomoses  between  the  anterior  branches  of  the  four  superioi 
cervical  nerves  constitute  the  cervical  plexus;  the  anterio; 
branches  of  the  four  inferior  cervical  are  much  larger  thai 
those  of  the  superior;  they  are  united  in  like  manner  t 
each  other,  and  to  the  anterior  branch  of  the  first  dorsal 
and  constitute  the  brachial  plexus  ;  these  two  plexuses  an< 
their  branches  the  student  may  next  dissect. 

The  CERVICAL  PLEXUS  is  formed  by  the  anterior  branche 
of  the  four  superior  cervical  nerves,  which  join  each  othe 
in  arches,  from  the  convexities  of  which,  branches  aris< 
that  again  join  in  a  similar  manner;  a  quantity  of  cellula 
membrane  is  entangled  in  the  areola?  between  these;  thi: 
plexus  is  situated  on  the  side  of  the  neck,  on  a  level  wit! 
the  second,  third,  and  fourth  vertebrae,  between  the  sterno 
mastoid  and  trapezius  muscles;  it  sends  off  severa 
branches  which  may  be  classed  into  ascending  and  de 
scending ;  the  former  consist  of  superficial  and  deep,  th< 
latter  of  internal  and  external ;  the  ascending  superficia 
branches  are  two  or  three  in  number,  they  ascend  obli 
quely  forwards  over  the  sterno-mastoid  muscle,  supply  th« 
platysma  arid  integuments  over  the  parotid  gland,  also  or 
the  ear  and  on  the  side  and  back  part  of  the  head,  ant 
communicate  freely  with  the  portio  dura  of  the  seventl 
pair  of  nerves ;  one  of  these  is  much  larger  than  the  others 
is  named  superficialis  or  ascendens  colli,  it  may  be  tracet 
chiefly  from  the  third  cervical,  and  is  lost  near  the  ear  anc 
in  the  parotid  gland  ;  this  nerve  accompanies  the  external 
jugular  vein.  The  deep  ascending  branches  of  the  plexuj 
are  small  nerves  which  supply  the  sterno-mastoid,  digas 
trie,  spleriius  and  adjacent  muscles,  and  communicate  witt 
the  neighbouring  nerves.  The  descending  branches  arc 
internal  and  external,  the  internal  are  two,  a  superficial 
and  a  deep ;  the  superficial  internal  descending  brand: 
joins  Ihe  descendens  noni,  and  assists  it  in  supplying  the 
superficial  muscles  on  the  forepart  of  the  neck.  The  deep 
internal  descending  branch  is  the  phrenic  nerve:  this  arise* 
from  the  lower  part  of  the  plexus,  chiefly  from  the  fourth 
cervical,  it  has  also  in  general  a  filament  or  two  from  the 
brachial  plexus,  [and  a  root  from  the  third  cervical  nerve  ;] 
the  phrenic  nerve,  or,  as  it  is  also  named,  the  internal  res- 
piratory nerve  descends  obliquely  inwards,  on  the  anterior 
scalenus  muscle. 

[At  the  junction  of  its  roots  from  the  third  and  fourth  cervical 
nerves,  it  is  at  the  outer  edge  of  the  scalenus  muscle  which  it  crosses 
obliquely,  B.J  as  to  enler  the  thorax  at  the  inner  edge  of  the  muscle.] 

At  the  lower  part  of  the  neck  it  communicates  with  the 
lower  cervical  ganglion,  and  often  with  the  vagus  or  its 
recurrent,  it  then  enters  the  thorax  between  the  subclavian 


DUBLIN    DISSECTOR.  335 

vein  and  artery,  and  descends  to  the  diaphragm  on  the  side 
of  the  pericardium  between  it  and  the  pleura;  the  right 
phrenic  is  nearly  perpendicular,  the  left  takes  an  oblique 
course  round  the  apex  of  the  heart,  it  is  therefore  longer 
and  lies  more  posterior  than  the  right.  On  the  diaphragm 
these  nerves  divide  into  several  branches,  some  of  which 
ramify  on  the  superior  surface  of  that  muscle,  others  on 
its  inferior  accompanying  the  phrenic  vessels.  These 
branches  on  the  right  side  send  some  filaments  to  the  infe- 
rior vena  cava  and  to  the  liver,  and  unite  with  the  nerves 
of  this  organ  and  with  those  of  the  stomach ;  on  the  left 
side  the  phrenic  nerve  sends  some  filaments  to  the  esopha- 
gus and  stomach,  these  communicate  with  the  vagus  and 
solar  plexus.  The  external  descending  branches  of  the 
cervical  plexus  are  numerous,  some  are  superficial,  others 
deep,  the  superficial  descend  to  the  clavicle  and  acromion 
process,  supply  the  superficial  muscles  in  their  course,  and 
terminate  in  the  pectoral  and  deltoid  muscles  and  in  the 
integuments ;  the  deep  branches  descend  behind  the  clav- 
icle, supply  the  deep  muscles  on  the  side  of  the  neck  and 
those  connected  to  the  scapula ;  one  of  these  branches  is 
remarkable  for  its  length,  it  is  of  the  same  size  as  the 
phrenic,  and  is  named  the  external  respiratory  nerve  of  the 
trunk ;  this  nerve  proceeds  from  the  back  part  of  the 
plexus,  chiefly  from  the  fourth  cervical,  it  has  also  fila- 
ments connecting  it  to  the  third  and  second,  and  to  the 
phrenic,  it  descends  behind  the  scaleni  muscles  and  be- 
neath the  trapezius  and  levator  anguli  scapula?,  and  is  al- 
most exclusively  distributed  to  the  serratus  magnus  muscle. 
The  BRACHIAL  [or  AXILLARY]  PLEXUS  isformed  by  the  junc- 
tion of  the  anterior  branches  of  the  fifth,  sixth,  seventh,  and 
eighth  cervical,  and  of  the  first  dorsal ;  this  plexus  is  broad 
and  flat,  the  nerves  forming  it  are  very  large,  particularly 
the  inferior ;  it  is  situated  at  the  inferior  and  lateral  part 
of  the  neck,  between  the  scaleni  muscles  and  above  the 
subclavian  artery,  it  then  descends  obliquely  outwards  be- 
neath the  clavicle  and  subclavian  muscle  and  over  the  first 
rib,  into  the  axilla,  where  it  rests  on  the  serratus  magnus 
behind  the  axillary  artery  and  vein.  The  fifth  and  sixth 
cervical  unite  first,  the  seventh  cervical  runs  alone  for  some 
distance,  the  eighth  cervical  and  first  dorsal  unite  imme- 
diately, so  that,  at  first,  this  plexus  consists  of  three  roots, 
these  "however  soon  unite;  in  the  axilla  they  again  sepa- 
rate and  interlace  [so  as  to  surround  the  axillary  artery 
like  a  braid,]  and  finally  subdivide  into  the  following 
branches,  the  thoracic,  supra  and  sub-scapular,  the  inter- 
nal and  external  cutaneous,  the  median,  ulnar,  musculo- 
epiral  and  circumflex. 


336  DUBLIN    DISSECTOR. 

1st.  The  thoracic  branches  arise  principally  from  the  up- 
per part  of  the  plexus,  they  are  four  o.r  live  in  number,  and 
divide  into  anterior  and  posterior ;  the  former  descend  be- 
hind the  clavicle  in  front  of  the  axillary  artery,  subdivide 
into  branches  which  accompany  the  thoracic  arteries,  sup- 
ply the  pectoral  muscles,  and  communicate  with  cutaneous 
branches  from  the  intercostal  nerves ;  the  posterior  thoracic 
nerves  descend  behind  the  vessels  to  the  serratus  magnus, 
posterior  scalenus  and  rhomboid  muscles. 

2nd.  The  supra-scapular  nerve  arises  from  the  upper  divi- 
sion of  the  plexus,  descends  obliquely  backwards,  parallel 
to  the  omo-hyoid  muscle,  to  the  superior  costa  of  the  scapu- 
la, and  passes  beneath  the  posterior  ligament  which  con- 
verts the  notch  in  this  part  of  the  bone  into  a  foramen ;  it 
then  gives  off  a  considerable  branch  to  the  supra-spinatus 
muscle,  and  proceeds  beneath  the  acromion  process  and 
behind  the  neck  of  the  scapula  to  the  infra-spinous  fossa, 
where  it  is  distributed  to  the  infra-spinatus  and  teres  minor 
muscles. 

3rd.  The  sub-scapular  nerves  are  three  or  four  in  number, 
they  arise  from  different  parts,  but  chiefly  from  the  upper 
division  of  the  plexus,  they  descend  behind  the  vessels,  and 
ramify  in  the  sub-scapular,  latissimus  dorsi,  and  teres  major 
muscles. 

4th.  Internal  cutaneous  nerve  is  a  long  but  delicate  nerve, 
it  arises  out  of  the  lower  division  of  the  plexus,  descends 
nearly  perpendicularly  along  the  inner  side  of  the  arm,  at 
first  covered  by  the  brachial  aponeurosis,  near  the  elbow 
it  becomes  cutaneous,  and  runs  parallel  to  the  basilic  vein, 
and  divides  into  two  branches,  an  external  and  internal ; 
the  external  passes  along  the  border  of  the  biceps  over  the 
bend  of  the  elbow  to  the  fore  arm,  where  it  divides  into 
several  filaments,  some  of  which  descend  in  the  integu- 
ments as  low  as  the  wrist,  and  communicate  with  the  other 
cutaneous  nerves ;  this  branch  generally  crosses  the  me- 
dian basilic  vein,  in  some  it  lies  superficial  to  it,  in  others 
behind  it ;  the  internal  branch  descends  towards  the  inter- 
nal condyle,  and  divides  into  several  filaments,  some  of 
which  descend  along  the  inner,  and  others  along  the  pos- 
terior part  of  the  fore  arm,  they  all  terminate  in  the  integ- 
uments. 

5th.  External  cutaneous  nerve,  or  musculo-culaneous  or  per- 
forans  Casserii,  is  larger  than  the  last,  and  arises  from  the 
upper  division  of  the  plexus,  it  descends  obliquely  out- 
wards, through  the  fibres  of  the  coraco-brachialis,  and  be- 
tween the  brachialis  anticus  and  the  biceps,  it  then  de- 
scends  along  the  outer  border  of  the  latter  to  the  bend  of 
the  elbow,  pierces  the  aponeurosis,  becomes  cutaneous,  and 


DUBLIN    DISSECTOR.  337 

descends  along  the  radial  side  of  the  fore  arm  to  the  wrist ; 
in  the  arm  this  nerve  gives  muscular  branches  to  the  cora- 
co-brachialis,  biceps,  and  brachialis  anticus,  in  the  latter 
muscle  it  frequently  communicates  with  the  median  nerve. 
At  the  elbow  this  nerve  is  situated  between  the  biceps  and 
supinator  longus,  and  behind  the  cephalic  vein,  along  the 
fore  arm  it  accompanies  this  vein,  and  is  often  superficial 
to  it ;  near  the  wrist  this  nerve  divides  into  an  anterior  and 
posterior  branch,  the  former  passes  to  the  ball  of  the  thumb 
and  palm  of  the  hand,  the  latter  to  its  dorsum. 

6th.  Median  or  brachial  nerve  is  the  largest  branch  of  the 
plexus,  it  generally  arises  by  two  roots,  a  small  external 
one,  which  is  in  common  with  the  external  cutaneous  from 
the  upper  part  of  the  plexus,  and  a  large  internal  one  from 
the  lower  division  of  the  plexus;  the  brachial  artery  in 
general  separates  these  two  roots,  which  soon  unite  into  one 
thick  cord. 

[I  have  seen  one  specimen,  in  which  the  first  root  above  described, 
came  off  as  usual,  but  the  second  came  off  by  two  fasciculi,  which 
soon  united  to  form  a  single  trunk,  after  which  the  two  roots  extended 
down  the  arm  about  three  inches,  and  then  united  over  the  brachial 
artery,  so  as  to  form  the  median  nerve.] 

It  descends  obliquely  outwards  along  the  inner  edge  of 
the  biceps,  as  far  as  the  bend  of  the  elbow,  and  in  this  part 
of  its  course  it  is  covered  only  by  the  skin  and  fascia,  si- 
tuated rather  to  the  outer  side  of  the  artery  above,  crossing 
over  it  about  the  middle  of  the  arm,  and  to  its  ulnar  side 
below;  at  the  b&nd  of  the  elbow  it  passes  deep  between 
the  supinator  longus  and  pronator  teres,  and  on  the  bra- 
chialis anticus  perforates  the  pronator,  and  then  descends 
along  the  middle  of  the  fore  arm,  between  the  superficial 
and  deep  flexors,  passes  beneath  the  annular  ligament  of 
the  carpus,  where  its  size  is  increased,  and  terminates  in 
the  palm  of  the  hand  by  dividing  into  five  branches.  In 
the  arm  the  median  nerve  gives  but  few  branches,  these 
are  small  and  unimportant ;  in  the  fore  arm  it  sends  seve- 
ral considerable  branches  to  the  superficial  and  deep  pro- 
nators  and  flexors,  but  not  to  the  supinators,  a  little  below 
the  elbow  it  also  gives  off  the  anterior  inter-osseal  nerve,  this 
accompanies  the  artery  of  the  same  name,  along  the  anterior 
surface  of  the  inter-osseous  membrane,  and  supplies  the 
deep  flexors ;  at  the  pronator  quadratus  it  divides  into  two 
branches,  one  to  supply  that  muscle,  the  other  traverses 
the  inter-osseous  space,  and  is  lost  on  the  dorsum  of  the 
carpus  and  metacarpus :  a  little  above  the  wrist,  the  me- 
dian nerve  gives  off  a  superficial  branch,  which  passes  over 
the  annular  ligament,  and  is  lost  in  the  integuments.  In 
the  palm  of  the  hand,  the  median  nerve  divides  into  five 
29 


338  DUBLIN    DISSECTOR. 

digital  branches,  the  two  first  pass  one  along  either  side  of 
the  thumb,  the  third  goes  to  the  radial  side  of  the  index  fin- 
ger, the  fourth  supplies  the  opposed  sides  of  the  index  and 
middle  finger,  and  the  fifth,  which  is  joined  by  a  small 
branch  from  the  ulnar  nerve,  supplies  the  opposed  sides  of 
the  middle  and  ring  fingers;  these  digital  branches  in  the 
palm  of  the  hand  are  superficial  to  the  tendons,  and  form 
an  arch  nearly  parallel  to  that  formed  by  the  ulnar  artery, 
the  branches  of  the  latter  and  digital  nerves  then  run  to- 
gether to  the  extremity  of  each  finger  ;  in  this  course  they 
supply  the  lumbricales,  the  integuments  of  the  hand  and 
fingers,  and  near  the  last  phalanx  of  each  ;  the  nerves,  en- 
large, become  red  and  soft,,  and  divide  into  numerous  fine 
branches,  which  are  lost  in  the  papilla?  of  the  cutis. 

7th.  Ulnar  nerve  arises  from  the  lower  part  of  the  plexus, 
descends  obliquely  backwards  along  the  triceps,  and  be- 
hind the  elbow  joint,  through  the  groove  between  the  in- 
ner condyle  and  the  olecranon  process  ;  it  then  passes  for- 
wards, and  descends  along  the  ulnar  side  of  the  fore  arm 
to  the  carpus,  and  passing  over  the  annular  ligament  close 
to  the  pisiform  bone,  ends  in  the  palm  of  the  hand,  in  two 
branches,  a  superficial  and  a  deep.  In  the  arm  this  nerve 
is  superficial,  and  gives  off  a  few  branches  to  the  triceps 
and  to  the  skin  ;  in  the  fore  arm  it  lies  on  the  flexor  pro- 
fundus,  and  between  the  flexor  sublimis  and  ulnaris ;  to 
these  muscles,  particularly  the  latter,  it  sends  several  fila- 
ments ;  a  little  above  the  wrist  it  gives  off  the  dorsalis  car- 
pi ulnaris,  a  large  branch  which  winds  round  the  ulna  to 
the  back  of  the  hand,  and  divides  into  several  long 
branches  which  are  lost  in  the  integuments  of  that  region 
and  of  the  three  inner  fingers,  and  anastomose  with  the 
radial  branch  of  the  musculo-spiral  nerve.  Of  the  termi- 
nating branches  of  the  ulnar  nerve,  the  superficial  is  the 
larger,  it  divides  into  three  branches,  which  supply  the 
muscles  and  both  sides  of  the  little  finger,  also  the  ulnar 
side  of  the  ring  finger ;  the  deep  palmar  branch  passes 
beneath  the  flexor  tendons,  runs  across  the  metacarpus,  and 
assists  in  forming  a  deep  palmar  arch,  the  branches  of 
which  are  lost  in  the  interossei  muscles. 

8th.  Musculo-spiral  nerve,  is  a  very  large  nerve,  it  pro- 
ceeds from  the  middle  and  lower  divisions  of  the  plexus, 
descends  obliquely  backwards  and  outwards  between  the 
three  portions  of  the  triceps,  round  the  humerus  to  its  ex- 
ternal side,  it  then  turns  obliquely  forwards  and  downwards 
towards  the  elbow,  between  the  supinator  longus  and  the 
brachialis  anticus,  and  there  divides  into  two  branches,  an  an- 
terior or  radial  branch,  and  a  posterior  or  interosseal  branch. 
In  its  course  down  the  arm  this  nerve  sends  several  branch- 


DUBLIN    DISSECTOR.  339 

es  to  the  triceps,  a  little  above  the  outer  condyle  it  gives  off 
a  large  cutaneous  branch  [ramus  superficialis  dorsalis] 
which  branch  descends  along  the  radial  side  of  the  fore 
arm  to  the  thumb :  at  the  bend  of  the  elbow  this  nerve 
sends  several  branches  to  the  long  and  short  supinators, 
also  to  the  extensors  of  the  carpus ;  on  the  surface  of  the 
supinator  brevis  it  expands  and  divides  into  its  terminating 
branches  ;  the  anterior  or  the  radial  nerve  [or  ramus  super- 
ficialis anterior]  descends  along  the  inner  side  of  the  supi- 
nator longus,  which  it  supplies,  and  external  to  the  radial 
artery;  about  the  middle  of  the  fore  arm  or  a  little  lower, 
this  nerve  passes  behind  the  tendon  of  the  supinator  longus, 
and  becoming  cutaneous  descends  behind  the  radius  to  the 
back  of  the  hand,  where  it  divides  into  two  considerable 
branches,  one  for  the  integuments  of  the  thumb,  the  other 
expands  on  the  dorsum  of  the  hand  and  supplies  the  index 
and  middle  fingers,  and  communicates  with  the  dorsalis 
ulnaris  nerve.  The  deep  branch  of  the  musculo-spiral 
nerve  or  the  posterior  inter-osseal  nerve,  [or  ramus  profundus 
dorsalis]  winds  backwards  round  the  upper  part  of  the 
radius  and  the  supinator  brevis,  it  then  descends  along  the 
back  part  of  the  fore  arm,  with  the  posterior  inter-osseal 
artery,  and  divides  into  several  branches  superficial  and 
deep,  which  supply  the  two  layers  of  extensor  muscles. 

9th.  Circumflex  or  articular  nene,  arises  from  the  lower 
part  of  the  plexus,  descends  round  the  lower  edge  of  the 
sub-scapular  muscle,  and  passing  backwards  and  outwards, 
leaves  the  axilla  by  a  large  opening  between  the  humerus 
and  the  long  head  of  the  triceps,  above  the  tendons  of  the 
latissimus  dorsi  and  teres  major  muscles,  and  below  the 
capsuiar  ligament  of  the  shoulder  joint,  it  then  winds  round 
the  neck  of  the  humerus,  attached  to  the  internal  surface 
of  the  deltoid  ;  in  this  course  the  nerve  sends  some  small 
branches  to  the  sub-scapular  and  the  adjacent  muscles^  it 
then  divides  into  two  branches,  a  superior  and  inferior, 
both  of  which  encircle  the  neck  of  the  humerus  and  send 
their  numerous  sub-di  visions  into  the  deltoid  muscle. 

The  DORSAL  NERVES  are  twelve  in  number,  the  first  pair 
passes  between  the  two  first  dorsal  vertebrae,  and  the  last 
pair  below  the  last  dorsal  vertebra,  they  also  all  divide  into  a 
posterior  and  an  anterior  or  intercostal  branch ;  the  pos- 
terior branches  are  small,  pass  backwards  between  the 
transverse  processes,  and  supply  the  muscles  and  integu- 
ments of  the  back  and  loins ;  of  the  anterior  branches  that 
of  the  first  dorsal  is  largest,  it  rises  above  the  neck  of  the 
first  rib,  and  joins  the  last  cervical  nerve  in  the  brachial 
plexus  :  the  anterior  branches  of  the  second  and  third  are 
smaller,  they  proceed  backwards  and  outwards  between 


340  DUBLIN    DISSECTOR. 

the  corresponding  ribs,  and  covered  internally  by  the 
pleura;  at  the  angle  of  each  rib  they  pass  between  the 
intercostal  muscles,  run  along  the  groove  in  the  lower 
edge  of  each  rib,  supply  the  surrounding  muscles,  and  op- 
posite the  axilla  each  sends  a  filament  across  this  cavity 
to  the  integuments  on  the  inner  and  buck  part  of  the  arm; 
these  filaments  are  named  the  nerves  of  Wrisberg,  or  the 
cutaneous  nerves  of  the  arm  ;  these  two  intercostal  or  spi- 
nal nerves  then  continue  on  in  their  course  below  the  first 
and  second  ribs,  and  ultimately  end  in  small  cutaneous 
and  muscular  branches,  which  are  lost  on  the  lateral  and 
forepart  of  the  thorax  ;  the  anterior  or  intercostal  branches 
of  the  remaining  nine  dorsal  nerves  all  pass  in  a  similar 
manner  between  the  ribs,  and  supply  not  only  the  inter- 
costal but  also  the  adjacent  muscles;  the  two  last  are 
chiefly  distributed  to  the  abdominal  muscles  and  to  the 
diaphragm ;  the  twelfth  dorsal  sends  a  branch  close  to  the 
vertebrae  to  join  the  first  lumbar ;  all  these  anterior  branch- 
es of  the  dorsal  nerves  opposite  the  neck  of  each  rib  are 
connected  by  one  or  two  short  branches  to  the  ganglions 
of  the  sympathetic. 

LUMBAR  NERVES  ;  of  these  there  are  five  pair,  they  are 
larger  than  the  dorsal,  like  them  they  divide  into  posterior 
and  anterior  branches ;  the  posterior  are  distributed  to  the 
lumbar  muscles ;  the  anterior  branches  unite  with  each 
other  in  the  substance  of  the  psoas  [magnus  muscle]  and 
form  the  lumbar  plexus;  this  long  and  somewhat  triangular 
plexus  is  situated  along  the  sides  of  the  four  inferior  lum- 
bar vertebrae :  it  communicates  above  with  the  last  dorsal 
and  below  with  the  first  sacral,  and  divides  into  the  follow- 
ing branches  ;  inguino-cutaneous,  anterior  crural,  obturator 
and  lumbo-saeral.  The  inguino-cutaneous  are  generally 
three  in  number ;  they  descend  from  the  two  first  lumbar 
nerves,  pass  through  the  psoas,  and  descend  behind  the  pe- 
ritonaeum ;  the  first  or  the  external  descends  obliquely  out- 
wards over  the  quadratus  lumborum  muscle  and  behind 
the  kidney,  to  the  middle  of  the  crest  of  the  ilium,  it  then 
sends  several  branches  to  the  abdominal  muscles,  and  di- 
vides into  a  cutaneous  branch  which  passes  to  the  integu- 
ments on  the  outer  part  of  the  thigh  and  into  the  external 
spermatic  nerve  which  passes  beneath  the  internal  oblique 
muscle,  attaches  itself  to  the  spermatic  cord,  and  distributes 
its  branches  to  the  cremaster  muscle  and  to  the  scrotum,  in 
the  male,  or  to  the  round  ligament  and  labium,  in  the  female ; 
the  second,  or  the  middle  inguino-cutaneous,  descends  internal 
to  the  last,  pierces  the  abdominal  muscles  close  to  the  an- 
terior superior  spine  of  the  ilium,  and  is  distributed  to  the 
skin  on  the  outer  part  of  the  thigh  ;  the  third*  or  internal  in- 


DUBLIN    DISSECTOR.  3^j 

guino-culaneous,  descend  internal  to  the  last,  and  divides 
near  Poupart's  ligament  into  two  branches;  one  accom- 
panies the  supermatic  vessels  and  is  lost  on  the  cord,  the 
other  follows  the  crural  vessels  and  is  lost  in  the  integu- 
ments and  glands  of  the  groin.  The  anterior  crural  nerve 
arises  in  the  lumbar  plexus  from  the  four  superior  nerves; 
it  perforates  the  psoas,  descends  obliquely  outwards  along 
its  external  side,  on  the  iliacus  internus,  covered  by  the 
iliac  fascia,  and  passes  beneath  Poupart's  ligament  [at  from 
a  quarter  to]  half  an  inch  external  to  the  femoral  artery  ; 
it  is  then  covered  by  the  fascia  lata,  becomes  flat  and 
broad,  and  divides  into  two  fasciculi,  a  superficial  and  a 
deep;  the  superficial  separates  into  four  or  five  long 
branches  which  pierce  the  fascia  lata  -and  descend  along 
the  inner  and  forepart  of  the  thigh  to  the  knee,  some  of 
these  accompany  the  saphena  vein. 

[Of  these  branches  the  four  principal  are  the  cutaneus  externus,  the 
cutaneus  medius,  the  cutaneus  anterior,  and  the  cutaneus  internus. 
The  first  is  distributed  to  the  integuments  over  the  vastus  externus  and 
rectus  muscles,  as  far  as  the  patella  ;  the  second  perforates  the  sartorius, 
near  the  inner  edge  of  the  rectus  muscle,  to  the  integuments  over  which 
it  is  distributed ;  the  third  is  internal  to  the  last,  crosses  the  sartorius 
below  it,  and  is  distributed  to  the  integuments  over  the  vastus  internus 
as  far  as  the  patella ;  the  fourth  is  still  more  internal,  and  is  distri- 
buted to  the  integuments  over  the  adductor  muscles,  at  the  fore  and 
inner  part  of  the  thigh,  some  of  its  filaments  reach  the  knee.] 

The  deep  fasciculus  is  larger,  it  immediately  divides  into 
numerous  muscular  branches,  which  supply  the  muscles  on 
the  outer  and  forepart  of  the  thigh;  they  are  divided  into 
the  external  and  internal  branches,  the  former  supply  the 
vastus  externus,  rectus,  iliacus  internus,  and  tensor  vaginae 
muscles  ;  the  internal  supply  the  sartorius,  vastus  internus, 
and  crurseus ;  three  or  four  accompany  the  femoral  artery 
near  to  the  knee ;  two  or  three  of  these  pass  into  the  adjoin- 
ing muscles,  and  one,  the  internal  saphenus  nerve,  continues 
to  descend  to  the  inner  side  of  the  knee  between  the  ten- 
dons of  the  gracilis  and  sartorius  ;  it  then  becomes  attached 
to  the  saphena  vein,  and  twines  round  this  vessel  as  far  as 
the  inner  side  of  the  foot ;  in  this  course  it  gives  i.u..ierous 
filaments  to  the  integuments  of  the  leg.  The  obturator  nerve 
is  smaller  than  the  preceding,  it  arises  chiefly  from  the  third 
lumbar,  it  perforates  the  psoas,  and  descends  obliquely  in- 
wards along  the  inner  side  of  that  muscle  to  the  obturator 
foramen,  through  the  upper  part  of  which  it  escapes  into 
the  groin,  where  it  is  covered  by  the  pectinseus,  and  where 
it  divides  into  its  two  branches  an  anterior  and  posterior, 
having  previously  sent  some  twigs  to  the  obturator  inter- 
nus; the  anterior  branch  is  lost  in  the  adductor  brevis, 
29* 


342  DUBLIN    DISSECTOR. 

pectinseus,  and  vastus  intermis,  and  communicates  with  the 
anterior  crural;  the  posterior  branch  supplies  the  gracilis 
the  adductor  magnus,  and  longus.  The  lumbo-sacral  nerve 
proceeds  from  the  fourth  and  fifth  lumbar  nerves  into  the 
pelvis,  and  soon  divides  into  two  branches,  the  superior 
glutseal,  and  the  communicating;  the  glutaal  escapes 
through  the  upper  part  of  the  sciatic  notch,  and  is  distribu- 
ted to  the  glutseus  medius  and  minimus  muscles  along  with 
the  branches  of  the  glutseal  artery  ;  the  communicating 
branch  joins  the  first  of  the  following  nerves  in  the  sacral 
or  sciatic  plexus. 

The  SACRAL  NERVES  are  five  pair,  [sometimes  six,]  they 
divide  within  the  spinal  canal  into  their  anterior  and  pos- 
terior branches,  the  latter,  very  small,  pass  through  the 
posterior  sacral  holes  and  supply  the  muscles  and  integu- 
ments :  the  anterior  branches  are  very  large,  particularly 
the  three  superior,  the  two  last  are  much  smaller ;  these 
five  nerves,  with  the  branch  from  the  last  lumbar,  form  the 
sacral  plexus,  large  and  flat,  placed  on  the  sacrum  and  pyri- 
form  'muscle  behind  the  rectum,  and  the  other  pelvic  vis- 
cera, it  sends  off  the  following  branches  both  internal  and 
external  ;  the  internal  or  pelvic  are  the  ha?morrhoidal  and 
vesical,  and  in  the  female  the  uterine  and  the  vaginal ;  the 
external  branches  are  the  inferior  or  lesser  sciatic,  the  in- 
ferior glutseal.  posterior  cutaneous,  pudic,  and  great  sciatic 
or  posterior  crural.  All  these  escape  by  the  lower  part  of 
the  great  sciatic  not-ch,  below  the  pyriform  muscle.  The 
lucmorrhoidal,  xesical,  uterine  and  vaginal  branches  are  all 
small  nerves  which  arise  from  the  upper  part  of  the  plexus, 
are  entangled  with  accompanying  vessels,  and  interlace 
with  each  other;  they  are  distributed  to  the  different  pelvic 
viscera,  as  their  names  imply.  The  lesser  sciatic  nerve  es- 
capes from  the  pelvis  with  the  sciatic  artery,  it  then  passes 
downwards  to  the  space  between  the  tuber  isr.hii  and  tro- 
chanter  major,  but  nearer  to  the  former,  round  which  it 
twines,  and  at  its  lower  part  divides  into  two  sets  of  branch- 
es, a  superficial  and  a  deep  ;  the  former  pass  over  the  ham- 
string r.rjs'les  with  the  posterior  cutaneous  nerve,  and  are 
lost  in  jViese  muscles  ;  and  the  latter  pass  under  the  mus- 
cles ana  ~are  distributed  to  the  quadratus  femoris,  upper 
part  of  the  adductor  magnus  muscles,  &c.  and  some  go  to 
the  hip  joint.  The  inferior  glutccal  nerve  leaves  the  pelvis 
below  ;!he  pyriform  mu?cle,  and  divides  at  once  into  several 
branches,  vhich  nre  principally  distributed  to  the  glutseus 
maximrs,  some  also  pass  to  the  perinaaum  and  to  the  inner 
side  of  the  thigh.  The  posterior  cutaneous  nerve  of  the  thigh 
arises  in  common  with  the  preceding  from  the  second  and 
third  sacral  nerves,  escapes  from  the  pelvis  below  the  py- 


DUBLIN    DISSECTOR.  343 

riform  muscle,  becomes  cutaneous,  and  descends  along  the 
back  part  of  the  thigh  and  leg,  and  communicates  with  the 
cutaneous  nerves  in  the  latter  region.  The  pudic  nerve  arises 
from  the  third  and  fourth  sacral,  passes  through  the  great 
sciatic  notch  internal  to  the  preceding;  it  then  re-enters 
the  pelvis  by  the  lesser  sciatic  notch,  and  passing  upwards 
and  forwards  along  the  internal  surface  of  the  tuber  ischii 
towards  the  pubis,  it  divides  into  two  branches,  an  inferior 
and  superior;  the  inferior,  [the  long  inferior  pudendal 
nerve]  ascends  obliquely  forwards  and  inwards  along  the 
ramus  of  the  ischium  to  the  perinasum,  and  is 'distributed  to 
the  muscles  and  integuments  in  that  region,  also  to  the 
scrotum  ;  the  superior  branch  [the  long  superior  pudendal 
nerve]  continues  its  course  along  the  ramus  of  the  pubis 
nearly  to  the  symphysis,  it  then  passes  forwards  along  the 
dorsum  of  the  "penis,  increases  in  size  as  it  approaches  the 
glans  penis,  in  the  subcutaneous  cellular  tissue  of  which  it 
terminates  ;  in  the  female  the  inferior  branch  of  the  pudic 
nerve  supplies  the  labium,  the  superior,  the  •clitoris. 

The  great  sciatic  or  posterior  crural  nerve  is  the  principal 
branch  of  the  sacral  plexus,  and  the  largest  nerve  in  the 
body ;  it  proceeds  from  the  four  superior  sacral  nerves, 
escapes  from  the  pelvis  below  the  pyriforrn  muscle,  some- 
times through  it,  it  then  descends  along  the  back  of  tho 
thigh  over  the  gemelli,  quadratus,  and  adductor  magnus  as 
far  as  the  ham,  where  it  divides  into  the  external  and  inter- 
nal popliteal  nerves;  in  this  course  this  nerve  is  covered 
superiorly  by  the  glutseus  maxirnus  and  the  hamstring 
muscles,  inferiorly  by  the  fascia  lata  and  the  integuments. 

[The  sciatic  nerve  sometimes  comes  out  from  the  pelvis  in  two 
trunks,  one  of  these  emerges  beneath  the  pyriform  muscle,  the  other 
perforates  the  substance  of  that  muscle-:  they  then  descend  sepa- 
rately,  and  one  becomes  the  external,  the  other  the  internal  popliteal 
nerve.] 

The  sciatic  nerve  sends  off  several  cutaneous  and  mus- 
cular branches,  the  latter  supply  the  hamstring  muscles, 
the  gracilis,  and  the  adductor  magnus.  The  external  pop- 
liteal, or  the  peronfcal  nerve,  descends  obliquely  outwards 
along  with  the  biceps  tendon  to  the  external  condyle  of 
the  femur,  it  then  turns  forwards  through  the  peronreus 
longus,  round  the  neck  of  the  fibula,  and  divides  into  two 
branches,  the  musculo-cutaneous  [or  external  peronreal] 
and  anterior  tibial ;  the  peronseal  nerve,  before  it  arrives 
at  the  head  of  the  fibula,  sends  off  two  long  branches, 
termed  the  peroneo-cutaneous  nerves  of  the  leg. 

[Of  thesw,  one,  the  internal  peroneo-cntaneous,  descends  'behind  the 
gastroenemius  muscle,  to  below  the  middle  of  the  leg,  when  it  unites 


344  DUBLIN    DISSECTOR. 

with  the  external  saphenus,  or  communicans  tibiae  a  branch  of  the 
posterior  tibial.  The  other,  the  external  peroneo-cutaneous,  is  distri- 
buted to  the  integuments  along  the  fibula.] 

The  musculo-cutaneous  nerve  descends  between  the  pe- 
ronseus  longus  and  extensor  digitorum  longus  ;  to  these  and 
to  the  short  peronaei  muscles  it  sends  several  muscular 
branches ;  about  the  middle  of  the  leg,  it  perforates  the 
fascia,  and  a  little  above  the  outer  malleolus  it  divides  into 
the  internal  and  external  tarsal  nerves  or  dorsal  nerves  of 
the  foot ;  the  internal  is  distributed  to  the  integuments  of 
the  first  and  second  toes,  and  communicates  with  the  inter- 
nal saphenus  nerve  and  with  the  anterior  tibial ;  the  exter- 
nal supplies  the  integuments  on  the  three  outer  toes,  and 
communicates  with  the  internal  branch  and  with  the  exter- 
nal saphenus  nerve.  The  anterior  tibial  nerve  descends  ob- 
liquely forwards  along  with  the  anterior  tibial  artery  be- 
tween the  tibialis  anticus  and  the  extensor  digitorum  longus 
and  extensor  pollicis,  which  muscles  it  supplies;  it  also 
sends  branches  through  the  fascia  to  the  integuments ;  it 
then  passes  beneath  the  annular  ligament  of  the  tarsus,  and 
runs  to  the  inter-osseous  muscle  between  the  two  first  meta- 
tarsal  bones ;  on  the  foot  it  sends  a  large  branch  to  the  exten- 
sor digitorum  brevis,.  also  several  cutaneous  and  communi- 
cating filaments,  and  it  terminates  by  supplying  the  first 
inter-osseal  muscle  and  the  integuments  of  the  two  internal 
toes  ;  in  the  first  inter-osseal  space  a  small  branch  commu- 
nicates with  the  plantar  nerves.  The  internal  popliteal  or 
posterior  tibial  nerve  is  larger  than  the  preceding  ;  it  descends 
nearly  vertically  between  the  heads  of  the  gastrocnemius 
and  solreus  muscles,  and  behind  the  articulation  of  the 
knee  and  the  poplitoeus  muscle  ;  it  then  descends  obliquely 
inwards  beneath  the  sola3us  and  on  the  tibialis  posticus  and 
flexor  digitorum  longus,  to  the  arch  beneath  the  heel  and 
the  internal  ankle;  it  here  divides  into  the  internal  and  ex- 
ternal plantar  nerves.  In  the  ham  a  quantity  of  fat  sepa- 
rates this  nerve  from  the  popliteal  vessels  ;  below  the  knee 
it  becomes  more  closely  connected  to  them,  lying  super- 
ficial and  a  little  to  their  inner  or  tibial  side ;  at  the  lower 
edge  of  the  poplitseus  it  passes  to  the  outer  or  fibular  side 
of  the  posterior  tibial  artery,  and  descends  in  that  relation 
to  this  vessel  as  far  as  the  internal  malleolar  region.  The 
posterior  tibial  nerve  above  the  knee  gives  off  a  small  nerve, 
the  posterior  or  external  saphenus;  this  descends  along  the 
back  of  the  leg,  at  first  covered  by  the  fascia,  afterwards  it 
is  subcutaneous  ;  it  communicates  superiorly  with  filaments 
from  the  cutaneous  branch  of  the  sciatic  plexus  and  with 
the  external  cutaneous  branches  of  the  peronceal  nerve ; 
about  the  middle  of  the  leg  it  is  increased  in  size  [by  uni- 


DUBLIN    DISSECTOR.  345 

ting  with  the  internal  peroneo -cutaneous  nerve,]  and  ac- 
companies the  external  saphena  vein  to  the  external  malle- 
olus,  behind  which  it  passes  ;  it  then  curves  forwards  along 
the  outer  edge  of  the  foot,  communicating  with  the  external 
dorsal  nerves  of  the  foot,  and  supplying  the  integuments 
and  muscles  on  the  outer  side  of  this  region.  In  the  ham, 
the  posterior  tibial  nerve  gives  off  several  very  large  mus- 
cular branches  to  the  gastrocnemius,  sola3us,  and  plantaris  ; 
and  in  its  course  down  the  leg  several  smaller  branches  to 
the  deep-seated  muscles ;  it  also  sends  numerous  filaments 
around  the  artery  ;  some  very  small  twigs  pass  through  the 
inter-osseous  space  along  with  the  anterior  tibial  artery  and 
join  the  anterior  tibial  nerve.  The  internal  plantar  nerve  is 
larger  than  the  external ;  it  passes  forwards  along  the  inner 
side  of  the  tarsus  above  the  abductor  pollicis,  sends  many 
branches  to  the  plantar  muscles  and  to  the  integuments, 
and  arriving  near  the  base  of  the  great  toe,  divides  into 
four  digital  branches  ;  the  first  runs  along  the  tibial  side  of 
the  first  toe  ;  the  second  subdivides  and  supplies  the  oppos- 
ed sides  of  the  first  and  second  toes  ;  the  third,  in  like  man- 
ner, the  second  and  third  toes  ;  and  the  fourth  the  opposed 
sides  of  the  third  and  fourth  toes :  these  digital  nerves  also 
supply  the  lumbricales,  and  communicate  with  the  dorsal 
nerves  of  the  foot.  The  external  plantar  nerve  passes  for- 
wards and  outwards  above  the  flexor  brevis  to  the  fifth  me- 
tatarsal  bone,  and  divides  into  two  branches  ;  one,  the  su- 
perficial, supplies  the  little  toe  and  the  outer  side  of  the 
fourth ;  the  deep  branch  passes  obliquely  inwards  across 
the  metatarsus,  and  supplies  the  inter-ossei  and  the  other 
deep  plantar  muscles. 


SECTION  IIL 

DISSECTION    OF    THE    GANGLIONIC    SYSTEM,    OR    GREAT 
SYMPATHETIC    NERVES. 

IN  addition  to  the  small  ganglions  already  noticed  in  the 
description  of  the  cerebral  nerves,  viz.  the  lenticular  or 
ophthalmic,  the  spheno-palatine,  or  Meckel's,  and  the  sub- 
maxillary,  also  the  several  ganglions  on  the  spinal  nerves, 
we  find  one  continued  chain  of  these  bodies  placed  anterior 
to  the  vertebral  column  on  either  side  of  the  median  line  ; 
these  ganglions,  on  each  side,  are  all  connected  to  each 
other,  and  resemble  a  knotted  cord ;  this  cord  receives  the 
name  of  the  sympathetic  nerve. 


340  DUBLIN    DISSECTOR. 

The  SYMPATHETIC  NERVES,  therefore,  are  two  in  number ; 
they  descend  from  the  base  of  the  cranium  perpendicularly 
along  the  neck,  placed  on  the  rectus  capitis  and  longus 
colli  muscles,  and  behind  the  great  vessels  and  nerves  ;  at 
the  upper  end  of  the  chest  each  of  these  nerves  is  divided 
by  the  subclavian  artery  into  several  branches,  which  en- 
circle that  vessel  and  unite  below  it  in  the  thorax  ;  through 
this  cavity  they  descend  at  first  obliquely  backwards  and 
outwards  along  the  heads  of  the  ribs  and  covered  by  the 
pleura ;  they  then  incline  a  little  forwards,  and  pass  behind 
the  true  ligamentum  arcuatum  into  the  abdomen  ;  through 
this  region  they  descend  obliquely  outwards  on  the  fore 
part  of  the  lumbar  vertebrae  and  between  the  psoas  muscle 
and  the  crus  of  the  diaphragm  ;  they  then  sink  into  the 
pelvis,  keeping  close  to  the  sacrum,  and  descend  along  the 
anterior  surface  of  this  bone  obliquely  inwards ;  near  its 
inferior  extremity,  or  on  the  first  part  of  the  coccyx,  these 
nerves  unite  and  terminate  in  a  small  ganglion  named  coc- 
cygeal  ganglion  or  ganglion  impar.  The  superior  extrem- 
ity of  each  sympathetic  nerve  is  connected  by  several  fila- 
ments to  several  of  the  cerebral  nerves ;  some  of  these 
connexions  have  been  improperly  termed  the  origin  of  the 
sympathetic ;  in  their  course  along  the  spinal  column  each 
nerve  regularly  communicates  with  every  pair  of  the  spinal 
nerves,  with  each  of  the  cervical  nerves  by  one  filament, 
and  with  each  of  the  dorsal,  lumbar,  and  sacral  nerves  by 
two ;  the  sympathetic  nerves  may  either  be  considered  as 
independent  parts  of  the  nervous  system  communicating 
by  numerous  branches  with  every  portion  of  that  system, 
or  they  may  each  be  regarded  as  a  nervous  cord  formed 
by  the  union  of  branches  from  all  the  spinal  and  from  seve- 
ral of  the  cerebral  nerves;  the  latter  is  probably  the  more 
correct  view.  The  sympathetic  nerves  send  otf  numerous 
branches,  which  are  chiefly  destined  to  supply  the  heart 
and  the  coats  of  the  great  vessels  and  all  the  pelvic  and 
abdominal  viscera ;  these  branches  arise  from  the  ganglions 
on  these  nerves  ;  of  these  there  are  generally  three  in  the 
neck ;  in  the  back  and  loins  they  correspond  with  the  num- 
ber of  vertebrse  in  those  regions,  and  in  the  pelvis  there  are 
three  on  each  side  and  the  coccygeal  or  impar  ganglion 
below ;  these  ganglions  and  their  branches  must  be  next 
examined. 

The  Cervical  Ganglions  are  three,  the  superior,  middle, 
and  inferior  ;  the  superior  cervical  ganglion  is  of  an  oval 
figure  and  reddish  colour,  extending  from  the  first  to  the 
third  cervical  vertebra,  placed  on  the  rectus  capitis  anticus, 
behind  the  carotid  artery  and  jugular  vein,  and  internal  to 
the  eighth  and  ninth  cerebral  nerves ;  this  ganglion  sends 


DUBLIN    DISSECTOR.  347 

off  several  branches,  viz.  superior,  inferior,  internal,  exter- 
nal, and  anterior  ;  the  superior  branches  are  two  in  num- 
ber; they  ascend  in  the  carotid  canal  to  the  cavernous 
sinus,  and  communicate  with  the  sixth,  and  with  the  vidian 
branch  of  the  fifth ;  in  this  situation  a  plexus  or  rather  a 
ganglion  may  be  observed  on  the  external  surface  of  the 
artery ;  fine  soft  reddish  filaments  pass  from  this  cavernous 
or  carotid  ganglion  to  the  several  nerves  which  compose  the 
orbital  plexus,  but  particularly  to  the  filament  of  the  nasal 
division  of  the  ophthalmic  which  is  destined  to  the  lenticu- 
lar ganglion,  also  to  the  Casserian  ganglion  of  the  fifth,  and 
several  continue  attached  to  the  carotid  artery,  and  are  lost 
on  its  cerebral  branches  and  in  the  tissue  of  the  brain, 
and  its  investing  membrane.  The  inferior  or  descending 
branches  of  the  superior  ganglion  are  small  filaments  to 
join  the  laryngeal  nerves  and  the  vagus,  the  superior  car- 
diac nerve,  (to  be  described  presently,)  and  the  continued 
cord  of  the  sympathetic  itself.  The  internal  branches 
unite  with  the  pharyngeai  plexus ;  the  external  join  the 
superior  cervical  nerves,  and  the  anterior  unite  with 
branches  of  the  vagus  and  the  facial,  and  form  a  plexus 
around  the  carotid  artery ;  from  this  several  branches  ex- 
tend along  the  external  carotid,  and  form  plexuses  around 
each  of  its  principal  branches,  which  are  named  accord- 
ingly. The  middle  cervical  ganglion  is  sometimes  wanting, 
[as  often  as  once  in  three  cases,  according  to  Meckel ; 
Horner,  however,  has  always  found  it,  although  sometimes 
very  small.]  It  is  smaller  than  the  superior,  of  a  triangular, 
often  an  irregular  form,  is  situated  behind  the  carotid  near 
the  curve  of  the  inferior  thyroid  artery,  opposite  the  fifth 
vertebra,  and  upon  the  longus  colli  muscle ;  it  sends  off 
branches  in  different  directions  which  communicate  with 
the  cervical  nerves  and  with  the  vagus  ;  it  also  sends  some 
filaments  to  join  the  cardiac  nerves.  The  inferior  cervical 
ganglion  is  of  an  irregular  figure ;  it  frequently  appears  to 
consist  of  several  small  ganglions  connected  to  each  other 
by  reddish  filaments  ;  it  is  situated  between  the  transverse 
process  of  the  last  cervical  vertebra  and  the  neck  of  the 
first  rib,  behind  and  on  either  side  of  the  vertebral  artery, 
and  between  the  scalenus  and  longus  colli  muscles;  fila- 
ments from  it  communicate  with  the  phrenic  nerve  and 
with  the  brachial  plexus  ;  several  also  encircle  the  subcla- 
vian  artery  and  extend  along  that  trunk  and  its  several 
branches,  particularly  along  the  vertebral  artery ;  from  it 
also  the  inferior  cardiac  nerves  proceed.  The  student  may 
next  examine  the  cardiac  nerves ;  there  are  three  on  each 
side,  they  are  named  superior,  middle,  and  inferior;  the 
superior  cardiac  nerve,  though  very  small,  takes  a  long 


348  DUBLIN    DISSECTOR. 

course  ;  it  arises  by  two  or  three  filaments  from  the  supe- 
rior cervical  ganglion,  descends  along  the  side  of  the  trachea 
behind  the  carotid  artery  to  the  chest ;  in  this  course  it 
communicates  with  the  faryngeal  nerves,  with  the  vagus, 
and  with  the  inferior  and  middle  ganglions  of  the  sympa- 
thetic ;  there  is  sometimes  a  small  ganglion  upon  it  near 
the  inferior  thyroid  artery  ;  at  the  lower  part  of  the  neck  it 
passes  behind  the  subclavian  vein  and  over  the  arteria  in 
nominata  ;  it  here  divides  into  several  filaments ;  some  pass 
along  the  coats  of  that  vessel  to  the  aorta,  others  join  the 
recurrent  nerve  and  the  middle  and  inferior  cardiac  nerves ; 
the  superior  cardiac  nerve  on  the  left  side  has  a  similar 
origin  and  course  in  the  neck,  but  it  enters  the  chest  in  a 
deeper  situation  than  the  nerve  of  the  right  side  ;  it  de- 
scends between  the  left  carotid  and  subclavian  arteries,  and 
arriving  at  the  arch  of  the  aorta,  divides  into  branches, 
some  of  which  pass  behind  that  vessel  and  join  the  cardiac 
ganglion ;  others  unite  with  the  cardiac  nerves  from  the 
sympathetic,  or  from  the  vagus  and  recurrent.  The  middle 
cardiac  nerve  on  the  right  side  is  generally  the  largest  of 
the  cardiac  nerves ;  on  the  left  side  it  is  sometimes  wanting, 
the  inferior  in  such  a  case  will  be  of  a  greater  size ;  it  arises 
by  several  filaments  from  the  middle  cervical  ganglion  or 
from  the  sympathetic  nerve  about  the  middle  of  the  neck ; 
it  descends  either  a  single  cord,  or  divided  into  several  pa- 
rallel filaments  behind  and  internal  to  the  carotid,  and  en- 
ters the  thorax  anterior  to  the  subclavian  artery  ;  it  here  is 
joined  by  large  branches  from  the  vagus  and  recurrent 
nerves,  it  then  descends  obliquely  inwards  along  the  side 
of  the  arteria  innominata,  glides  between  the  arch  of  the 
aorta  and  the  division  of  the  trachea,  and  terminates  in  the 
cardiac  ganglion  or  plexus.  On  the  left  side  the  middle 
cardiac  nerve  sometimes  arises  from  the  inferior  cervical 
ganglion  ;  it  enters  the  chest  along  the  subclavian  artery, 
and  either  joins  the  inferior  cardiac  nerve  or  enters  the  car- 
diac plexus.  The  inferior  cardiac  nerve  or  nerves  proceed 
from  the  inferior  cervical  ganglion,  and  on  the  right  side 
descend  along  the  arteria  innominata  to  the  arch  of  the 
aorto,  round  which  they  pass  to  its  forepart,  and  terminate 
principally  in  the  anterior  cardiac  plexus  ;  some  branches 
pass  between  the  aorta  and  pulmonary  artery  to  the  car- 
diac ganglion  ;  these  inferior  cardiac  nerves  communicate 
with  the  preceding,  and  with  the  vagus  and  its  recurrent; 
they  form  an  irregular  network  or  plexus  in  their  course 
to  the  aorta  ;  on  the  left  side  these  nerves  accompany  the 
subclavian  artery  and  partly  join  the  middle  cardiac  nerve, 
and  partly  the  cardiac  plexus. 

The  cardiac  plexus  is  situated  behind  the  ascending  aorta 


DUBLIN    DISSECTOR.  349 

near  its  origin,  and  in  front  of  the  trachea  and  of  the  right 
pulmonary  artery ;  it  consists  of  a  plexus  of  nerves  form- 
ed by  the  cardiac  nerves  from  opposite  sides,  also  by 
branches  from  the  eighth  pair  and  the  recurrent  nerves ;  in 
the  meshes  of  this  plexus  several  small  ganglions  are  en- 
closed, and  to  the  aggregate  of  these  the  term  cardiac  gan- 
glion is  applied ;  this,  which  is  of  a  greyish  colour  and  ir- 
regular form,  receives  superiorly  and  laterally  the  middle 
cardiac  nerves  from  each  side,  also  some  filaments  from  the 
superior  cardiac,  particularly  on  the  left  side,  and  also 
some  from  the  inferior  cardiac,  particularly  on  the  right 
side ;  the  greater  portion  of  the  right  superior  cardiac  joins 
the  middle  cardiac  before  the  latter  arrives  at  the  plexus, 
and  the  inferior  is  chiefly  distributed  on  the  fore  part  of  the 
aorta  to  the  anterior  cardiac  plexus.  From  the  great  car- 
diac plexus  branches  proceed  in  various  directions ;  some 
pass  backwards,  encircling  the  posterior  coronary  artery, 
and  forming  a  plexus  around  it,  and  accompanying  its 
branches  into  the  substance  of  the  heart,  others  pass  for- 
wards round  the  aorta,  from  the  anterior  cardiac  plexus  on 
it  and  on  the  right  pulmonary  artery,  and  vena  cava  ;  from 
this  plexus  branches  descend  over  the  right  auricle,  accom- 
pany the  anterior  coronary  artery,  and  form  plexuses 
around  it  and  its  several  branches ;  from  this  ganglion  also 
numerous  nerves  descend  on  either  side  along  the  pulmo- 
nary vessels,  and  communicate  with  the  pulmonary  plexus  ; 
on  the  left  side  these  branches  encircle  the  ductus  arterio- 
sus. 

The  sympathetic  nerves  in  the  thorax  have  twelve  gan- 
glions on  each  side,  sometimes  only  eleven,  the  last  cervi- 
cal and  first  dorsal  being  then  united  ;  each  of  the  thoracic 
ganglions  is  small  and  triangular,  the  base  towards  the 
spine,  the  apex  externally,  covered  by  the  pleura  and 
placed  on  the  heads  of  the  ribs ;  the  first  ganglion  is  the 
largest ;  they  all  communicate  by  one  or  two  branches, 
which  ascend  obliquely  outwards,  with  the  anterior  or  in- 
tercostal branch  of  the  spinal  nerves  ;  from  the  base  or  an- 
terior edge  of  each  ganglion  small  branches  pass  forwards 
to  the  mediastinum,  ramify  on  the  aorta  and  adjacent  ves- 
sels, and  communicate  with  the  pulmonary  plexus.  From 
the  six  inferior  ganglions  the  splanchnic  nerves  arise ;  these 
are  two  iu  number  on  each  side,  the  greater  and  lesser  or 
upper  and  lower. 

The  great  splanchnic  nerve  arises  by  four  or  five  distinct 
roots  from  the  sixth,  seventh,  eighth,  ninth,  and  tenth  gan- 
glions, they  descend  obliquely  forwards  and  unite  on  the 
tenth  dorsal  vertebra  into  one  cord,  which  enters  the  abdo- 
men either  along  with  the  aorta  or  separated  from  it  by  a 
30 


350  DUBLIN    DISSECTOR. 

fasciculus  of  the  diaphragm ;  each  nerve  then  expands  into 
the  semilunar  ganglion.  The  lesser  splanchnic  nerve  arises 
by  two  roots  from  the  tenth  and  eleventh  ganglions,  they 
unite  on  the  side  of  the  last  dorsal  vertebra ;  this  small 
nerve  then  enters  the  abdomen  through  the  crus  of  the 
diaphragm  external  to  the  great  splanchnic  nerve,  with 
which  it  communicates,  and  then  ends  [in  two  branches, 
one  of  which  joins  the  great  splanchnic  nerve,  while  the 
other  runs  into  the  renal  plexus.] 

In  the  abdomen  we  find  the  semilunar  and  the  lumbar 
ganglions  on  the  sympathetic  nerve  of  each  side  ;  the  semi- 
lunar  ganglion  of  each  side  is  situated  on  the  diaphragm, 
and  partly  on  the  aorta  on  either  side  of  the  cosliac  axis, 
and  above  and  behind  the  supra-renal  capsule.  These  are 
the  largest  ganglions  on  the  sympathetic,  they  communicate 
with  each  other  by  several  filaments  on  which  small  gan- 
glions are  placed ;  this  communication  surrounds  the  coe- 
liac  axis,  and  is  termed  the  solar  plexus  ;  this  plexus  is  si- 
tuated behind  the  stomach,  in  front  of  the  aorta  and  above 
the  pancreas ;  from  it  numerous  nerves  pass  off  in  various 
directions ;  these  nerves  accompany  the  blood  vessels,  and 
form  plexuses  around  each,  which  are  named  according  to 
their  destination,  hepatic,  splenic,  and  gastric  [or  superior  co- 
ronary ;]  these  plexuses  communicate  with  the  eighth  pair ; 
from  the  solar  plexus,  branches  descend  in  front  of  the 
aorta  ;  these  subdivide  at  the  renal  and  mesenteric  arteries, 
accompany  these  vessels,  form  plexuses  around  each,  which 
are  named  accordingly  the  renal,  superior,  and  inferior  me- 
senteric plexuses,  into  each  of  these,  branches  from  the  lum- 
bar ganglions  enter.  The  lesser  splanchnic  nerve  enters 
the  renal  plexus ;  from  which  on  each  side  descends  the 
spermatic  plexus,  this  in  the  male  follows  the  spermatic  ves- 
sels and  supplies  the  testicle  ;  in  the  female  it  enters  the 
pelvis  and  supplies  the  ovarium  and  uterus.  From  the  in- 
ferior mesenteric  plexus  branches  descend  to  the  edge  of 
the  pelvis,  unite  with  others  from  the  lumbar  ganglions, 
and  form  a  plexus  around  the  internal  iliac  or  hypogast.ric 
artery  and  its  pelvic  branches ;  this  is  termed  the  hypogas- 
tric  plexus ;  it  is  joined  by  numerous  filaments  from  the 
lumbar  and  sacral  ganglions  of  the  sympathetic,  and  it 
communicates  with  the  pelvic  branches  of  the  sacral  plexus. 

The  lumbar  or  abdominal  ganglions  of  the  sympathetic  are 
five  on  each  side,  sometimes  only  four  or  three ;  they  are 
situated  on  the  anterior  and  lateral  parts  of  the  bodies  of  the 
vertebrae  internal  to  the  psoas  muscle,  are  of  an  oval  figure, 
but  smaller  than  the  cervical ;  each  ganglion  is  connected  by 
one  or  two  communicating  branches  which  pass  through 
the  psoas  to  the  anterior  branches  of  the  spinal  nerves ; 


DUBLIN    DISSECTOR  351 

from  the  fore  part  of  each,  several  filaments  pass  in  front 
of  the  aorta  and  assist  in  the  formation  of  the  different  ab- 
dominal plexuses  which  are  principally  derived  from  the 
solar  plexus. 

The  sacral  or  pelvic  ganglions  are  three  or  four  in  number 
on  each  side  ;  the  first  is  oval,  the  remaining  are  of  an  ir- 
regular form :  they  each  communicate  with  the  sacral 
nerves  and  send  filaments  to  the  hypogastric  and  pelvic 
plexuses;  from  the  last  ganglion  on  each  side  a  small 
branch  passes  inwards  in  front  of  the  coccyx ;  these 
branches  unite  in  the  middle  line  and  form  a  small  plexus  ; 
sometimes  a  distinct  ganglion  (ganglion  impar)  is  placed 
here :  from  the  convexity  of  the  arch  which  these  branches 
form,  filaments  pass  off  to  the  coccygeei,  levatores,  and 
sphincter  ani  muscles. 


CHAPTER  IV. 

ORGANS  OF  SENSE. 

UNDER  this  head  may  be  placed  the  anatomy  of  the  nose, 
or  the  organ  of  smell ;  the  tongue,  or  the  organ  of  taste ; 
the  eye,  or  the  organ  of  vision  ;  and  the  ear,  or  the  organ 
of  hearing ;  to  these  may  be  added  the  integuments  or  the 
organs  of  touch. 


SECTION  I. 

ANATOMY    OF    THE    NOSE. 

SEVERAL  bones  enter  into  the  formation  of  this  organ  ; 
these  are  all  covered  by  a  very  delicate  periosteum,  which 
is  almost  inseparably  united  to  the  highly  sensible  lining 
mucous  membrane ;  to  the  anterior  part  of  the  bones  of 
the  nose,  the  cartilages,  which  form  the  septum  and  alee 
nasi,  are  attached.  The  nose  is  bounded,  superiorly,  by 
the  nasal,  frontal,  ethmoid  and  sphenoid  bones ;  the  roof 
of  the  nose  is  arched,  and  has  different  aspects,  the  anterior 

Sart  looks  downwards  and  backwards,  the  middle  perpen- 
icularly  downwards,  and  the  posterior  part  downwards 
and  forwards ;  the  floor  of  the  nose  which  is  nearly  hori- 
zontal, but  with  a  slight  inclination  backwards,  and  con- 
cave in  the  transverse  direction,  is  formed  by  the  palatine 


352  DUBLIN    DISSECTOR. 

plates  of  the  maxillary  and  palate  bones;  the  nose  is 
bounded  on  either  side  by  the  superior  maxillary,  unguis, 
spongy,  ethmoid  and  palate  bones,  and  by  the  internal 
pterygoid  plates.  It  is  divided  into  two  symmetrical  por- 
tions (the  nares)  by  the  septum,  which  is  composed  of  the 
azygos  plate  of  the  sphenoid,  the  nasal  lamella  of  the  eth- 
moid, the  vomer,  the  spines  of  the  palate  and  maxillary 
bones,  and  by  a  cartilage  ;  the  external  wall  of  each  naris 
is  deeply  grooved  by  three  fossae  or  meatuses,  the  superior, 
middle,  and  inferior,  these  are  situated  between  the  spongy 
bones,  the  middle  is  the  widest.  The  nasal  or  lachrymal 
duct  opens  into  the  anterior  third  of  the  inferior  meatus ; 
the  Eustachian  tube  opens  behind,  but  on  a  level  with  the 
inferior  spongy  bone,  and  at  the  side  of  the  septum  anteri- 
orly may  be  observed  the  superior  orifice  of  the  anterior 
palatine  canal,  which,  although  a  distinct  opening  superi- 
orly towards  the  cavity  of  the  nose,  yet  inferiorly  towards 
the  mouth,  forms  with  the  one  of  the  opposite  side  a  com- 
mon foramen ;  this  communication,  however,  between  the 
nose  and  mouth  does  not  exist  in  the  recent  state  in  the 
human  subject,  but  does  so  in  some  animals,  and  in  these 
Jacobson  has  ascribed  a  peculiar  office  to  it.  Into  the  mid- 
dle meatus,  the  antrum  maxillare  opens  by  a  small  oblique 
slit,  which  looks  backwards  and  inwards,  and  although  in 
the  dry  bone  it  appears  tolerably  large,  yet  in  the  recent 
state  it  admits  only  a  crow  quill  on  account  of  the  mucous 
membrane  being  thrown  into  a  small  fold  which  surrounds 
it:  in  front  of  this  is  a  groove,  named  the  infundibulum, 
which  leads  from  the  frontal  sinus,  into  this  groove  the  an- 
terior ethmoid  cells  open.  Into  the  upper  meatus,  the  poste- 
rior ethmoid  cells  and  the  sphenoid  sinus  open.  Each 
naris  opens  posteriorly  into  the  pharynx,  above  the  velum, 
by  an  oblong  oval  opening ;  these  are  separated  from  each 
other  by  the  vomer,  the  internal  pterygoid  plates  bound 
them  externally,  the  sphenoid  above  and  the  palate  bones 
below. 

To  the  anterior  edge  of  each  naris  the  cartilages  compo- 
sing the  alse  nasi  are  attached,  these  are  five  in  number, 
one  in  the  centre,  two  at  each  side ;  the  central  cartilage  is 
triangular  and  vertical,  attached  superiorly  and  posteriorly 
to  the  bony  septum,  its  anterior  edge  is  thick  and  sub-cuta- 
neous, and  attached  on  either  side  to  the  lateral  cartilages ; 
the  lateral  cartilages  are  two,  one  superior  and  triangular, 
attached  to  bone,  the  other  inferior,  and  irregularly  curved, 
convex  externally,  and  attached  to  the  preceding  and  to 
the  septum ;  in  the  ate  nasi  small  pieces  of  cartilage  also 
may  be  noticed  distinct  from  the  larger  cartilages.  All  the 
internal  surface  of  the  nose  and  of  the  sinuses  communi- 


DUBLIN    DISSECTOR.  353 

eating  with  it,  are  lined  by  a  soft,  vascular,  and  highly 
sensible  mucous  membrane;  this  is  the  pituitary  OT  Schnei- 
derian  membrane ;  this  mucous  membrane  is  continuous  an- 
teriorly with  the  integuments :  it  adheres  to  all  the  internal 
surface  of  the  bones  of  the  nose,  lines  the  sinuses,  is  con- 
tinuous through  the  nasal  duct  with  the  membrana  con- 
junctiva of  each  orbit ;  round  the  lower  extremity  of  each 
duct  it  forms  a  slight  circular  fold ;  and  posteriorly  it  is 
continuous  with  the  membrane  of  the  pharynx  and  Eus- 
tachian  tubes;  this  membrane  adheres  in  some  places  in- 
separably to  the  periosteum,  so  as  to  deserve  the  name  of 
a  fibro-mucous  membrane,  in  others  it  is  villous,  very  vas- 
cular, soft  and  thick  as  on  the  septum  and  turbinated  bones, 
and  in  these  situations  it  and  the  submucous  tissue  are  loose, 
cellular,  or  spongy,  and  probably  possess  some  of  the  pro- 
perties of  erectile  tissue :  at  the  extremities  of  the  latter  it 
forms  thick  fleshy-looking  folds  or  lips ;  in  the  sinuses  it  is 
pale  and  thin ;  it  is  constantly  moistened  with  a  mucous 
secretion,  but  mucous  glands  are  not  distinct  in  it.  The 
olfactory  or  first  pair  of  nerves  are  distributed  to  it  on  the 
septum  and  sethmoidal  region  in  the  form  of  numerous 
plexuses,  it  is  also  supplied  very  generally  with  branches 
from  the  ophthalmic  and  superior  maxillary  divisions  of 
the  fifth  pair ;  the  first  pair  are  generally  believed  to  endow 
the  superior  portion  of  this  membrane  with  its  peculiar 
sense  or  power  of  smelling ;  while  its  acute  sense  of  touch 
depends  on  the  fifth  pair,  the  nerve  of  feeling  for  the  head 
generally.  Majendie,  also,  has  recently  made  some  exper- 
iments to  prove  that  the  branches  of  the  fifth  pair  in  the 
nose  are  very  sensible  to  acid  or  pungent  odours,  in  the 
same  manner  as  the  surface  of  the  eye,  and  that  so  far 
they  may  be  accessory  to  the  function  of  this  organ. 

[The  arterial  distribution  upon  the  lining  membrane  of  the  nose,  is 
derived  from  the  palatine,  spheno-palatine,  und  infra-orbital  branches 
of  the  internal  maxillary  artery  ;  and  from  the  anterior  and  posterior 
ethmoidal  branches  of  the  ophthalmic  artery.  The  veins  for  the  most 
part  follow  the  course  of  the  arteries. 

The  septum  of  the  nose  is  sometimes  inclined  to  the  one  side  or 
the  other,  so  as  to  divide  the  nares  very  unequally ;  sometimes  the 
septum  is  deficient  either  in  its  bony  or  cartilaginous  portion.  In  the 
museum  of  the  college  is  a  preparation,  in  which  the  anterior  open, 
ing  of  the  left  naris,  is  very  small,  that  of  the  right  natural ;  poste- 
riorly the  nares  are  entirely  cut  off  from  the  fauces,  by  a  membrane, 
except  on  the  right  side,  where  there  is  an  opening  large  enough  to 
admit  the  end  of  the  finger ;  no  uvula  is  to  be  seen,  and  the  malfor- 
mation appears  as  though  the  velum  had  become  adherent  posteriorly, 
except  at  the  opening  referred  to.  A  flexible  bougie  introduced  into 
either  of  the  anterior  openings  of  the  nose  is  easily  carried  down  into 
the  pharynx  through  the  opening  in  the  preternatural  septum.  This 
30* 


354  DUBLIN    DISSECTOR. 

was  probably  a  congenital  malconformation,  and  it  would  have  been 
a  point  of  physiological  interest,  to  have  ascertained  the  condition  of 
the  sense  of  smell,  but  unfortunately  it  was  a  common  dissecting 
room  subject,  and  its  history  was  unknown. 

Another  deformity  which  sometimes  exists,  is  a  deficiency  of  the 
bony  septum,  between  the  nose,  and  the  mouth,  or  the  cleft  palate ; 
this  may  occur  either  singly, or  conjointly  with  hair  lip;  it  may  also 
be  combined  with  a  deficiency  in  the  alveolar  margin  of  the  superior 
maxillary  bone.  There  is  a  preparation  in  the  college  museum  or 
the  head  of  a  negro,  about  forty  years  of  age,  in  which  the  three  de 
fects  above  referred  to  were  combined.  In  the  first  place  there  was 
a  large  hair  lip,  behind  which  was  a  fissure  through  the  alveolar  mar- 
gin of  the  maxillary  bone,  behind  which  again,  was  a  cleft  through 
the  palatal  processes  of  the  maxillary  and  palate  bones,  the  vomer 
being  reflected  to  the  left  side  so  that  the  left  nostril  is  entirely  sepa- 
rated from  the  mouth,  while  the  right  nostril  and  mouth  form  one 
cavity.  Congenital  deformity  of  the  external  nose  is  rare,  but  loss 
of  substance  from  disease,  sometimes  occurs,  for  the  cure  of  which 
deformity  the  rhinoplastic  or  taliacotian  operations  have  been  per- 
formed  successfully.  The  spongy  bones  of  the  nose  are  sometimes 
destroyed  by  secondary  syphilis.  The  lining  membrane  is  the  seat  of 
acute  and  chronic  inflammation  and  of  hemorrhage  or  epistaxis. 
This  membrane  is  also  the  seat  of  polypes,  which  occur  at  all  ages, 
but  most  commonly  in  adults,  and  old  people:  they  are  of  two  kinds, 
malignant,  and  non-malignant ;  and  are  apt  to  recur  after  extirpa- 
tion ;  they  are  also  divided  according  to  their  structure,  into  gela- 
tinous, fibrous,  and  vascular.] 


SECTION  II. 

ORGAN    OF    TASTE. 

THE  organ  af  taste  resides  in  the  mucous  membrane  of 
the  tongue;  this  membrane  is  spread  over  the  muscular 
substance  of  the  tongue,  adheres  closely  to  it,  and  presents 
a  number  of  projections  or  papillae ;  the  tongue  is  very 
vascular  and  is  supplied  with  six  nerves ;  the  gustatory  is 
distributed  anteriorly  and  chiefly  to  the  conical  or  erectile 
papillae,  also  to  two  of  the  salivary  glands  on  each  side ; 
the  lingual  to  the  inferior  surface  and  to  its  muscular  sub- 
stance; the  glosso-pharyngeal  to  the  muscular  substance 
and  mucous  membrane  at  its  base ;  experiments  have 
proved  that  the  fifth  nerve  endows  this  organ  with  its  pe- 
culiar sense,  that  of  taste  ;  and  that  the  lingual  or  ninth  is 
its  motor  nerve ;  the  glosso-pharyngeal  is  probably  a  sen- 
tient nerve  to  the  posterior  part  of  the  tongue,  it  may  also 


DUBLIN     DISSECTOR.  355 

connect  this  organ  in  sympathy  with  the  stomach  and  the 
respiratory  organs :  the  form  and  structure  of  the  tongue 
have  been  already  described  under  the  anatomy  of  the 
mouth  and  pharynx,  (see  p.  39.) 


SECTION  III. 

ANATOMY    OF    THE    EAR. 

THE  parts  composing  this  complicated  organ  may  be  di- 
vided into  three  classes ;  the  first  includes  the  external  ear, 
or  the  cartilages  and  meatus  extemus ;  the  second  the 
tympanum  with  the  Eustachian  tube,  ossicula  auris  with 
their  muscles  and  nerves,  the  mastoid  cells,  the  pyramid, 
promontory,  &c. ;  the  third,  the  labyrinth  or  internal  ear, 
which  includes  the  vestibule,  semi-circular  canals,  cochlea, 
and  meatus  internus  with  the  portio  mollis. 

[The  muscles  of  the  ear  are  arranged  in  three  groups,  the  first 
group  consists  of  three  muscles,  situated  on  the  side  of  the  head,  and 
acting  upon  the  external  ear,  so  as  to  move  it  upon  the  head,  these 
muscles  are  well  developed  and  very  active  in  the  inferior  animals. 
The  second  group  consists  of  five  muscles,  is  situated  upon  the  auri- 
cle itself,  and  acts  upon  its  different  parts,  so  as  to  separate  or  ap- 
proximate them  ;  the  muscles  of  this  group  are  also  better  developed, 
and  more  active  in  the  inferior  animals,  than  in  man.  The  third 
group  consists  of  three  muscles,  some  say  of  four,  which  are  situated 
in  the  internal  ear,  and  act  upon  the  small  bones  of  the  ear  so  as  to 
render  the  membrana  tympani  tense  or  relaxed  as  the  case  may  be. 

First  Group,  three  Muscles. 
Superior  Auris,  or  Attollens,       Vide  p.  6. 
Anterior  Auris,  or  Attrahens,   )  yi^e  p  7 
Posterior  Auris,  or  Retrahens,  \ 

Second  Group,  five  Muscles. 
Tragicus,  1 

Anti-Tragicus, 

Helicis  Major,  }>  Vide  p.  356. 

Helicis  Minor, 
Transversalis  Auris,   J 

Third  Group,  three  Muscle* 
Stapedius,  i 

Tensor  Tympani,     >  Vide  p.  358. 
Laxator  Tympani,  S 

The  auricle  is  united  to  the  side  of  the  head  by  three  ligaments 


356  DUBLIN    DISSECTOR. 

which  lie  directly  behind  the  muscles,  which  move  the  auricle  upon 
the  head.] 

The  external  ear  consists  of  the  pinna  or  auricle  and  the 
meatus  externus;  the  pinna  is  composed  of  a  thin  fibro- 
cartilaginous  plate,  curved  in  different  directions,  so  as  to 
present  different  eminences  and  depressions ;  the  convex 
edge  which  forms  the  outline  of  it  is  the  helix,  below  this 
is  a  short  semicircular  fold,  the  anti-helix,  this  divides  su- 
periorly into  two  crura ;  the  depression  between  these  is 
the  fossa  navicularis;  in  front  of  the  meatus  is  an  eminence, 
the  tragus,  directed  backwards  over  the  meatus ;  opposite 
to  this  is  a  slight  projection  ;  the  anti-tragus ;  within  these 
several  eminences  is  a  deep  conical  cavity,  the  concha, 
which  leads  to  the  meatus  externus,  below  this,  is  the  pen- 
dulous fold  of  the  integuments,  or  the  lobe  of  the  ear ;  these 
several  eminences  are  supposed  to  be  of  use  in  protecting 
the  internal  parts,  also  in  collecting  and  directing  the  sound 
towards  the  meatus.  In  some  subjects  pale  muscular  fibres 
may  be  found  on  these  eminences,  they  have  been  named 
according  to  their  situation,  as  distinct  muscles,  tragicus, 
anti-tragicus,  major  and  minor  helicis,  and  transversalis 
auris ;  these  fibres  may  have  some  power  in  approximating 
these  cartilages,  and  thus  deepening  the  concha,  they  are 
seldom  marked  in  the  human  subject,  but  in  the  lower 
classes  of  animals  they  are  strong  and  distinct.  The  mea- 
tus auditorius  externus  extends  from  the  concha  to  the  mem- 
brana  tympani,  first  forwards,  upwards,  and  inwards,  then 
downwards  and  inwards ;  it  is  therefore  curved,  or  concave 
downwards,  about  an  inch  in  length,  one-half  cartilagin- 
ous, the  other  osseous. 

[In  consequence  of  which  when  wishing  to  examine  the  bottom  of 
the  ear,  the  external  ear  must  be  drawn  upwards,  and  backwards  ; 
the  passage  may  also  be  distended  in  its  cartilaginous  portion  by  the 
use  of  the  speculum  auris  ;  this  canal  is  three  lines  in  diameter.] 

It  is  lined  by  the  skin,  beneath  which  are  a  number  of 
ceruminous  glands,  it  is  also  furnished  with  a  number  of 
fine  hairs,  which  are  longer  and  more  obvious  externally ; 
the  cuticle  is  continued  also  over  the  membrana  tympani, 
from  which  it  readily  separates. 

The  middle  ear  consists  of  the  tympanum  and  its  appen- 
dages. The  membrana  tympani  separates  this  cavity  from 
the  meatus  externus,  the  latter  must  be  cut  vertically  to 
expose  this  membrane ;  it  is  placed  obliquely,  its  lower 
edge  being  more  internal  than  the  upper,  or"  nearer  the 
median  line,  it  therefore  looks  downwards,  outwards,  and 
forwards;  it  is  concave  towards  the  meatus,  convex  to- 
wards the  tympanum,  being  drawn  in  the  latter  direction 


DUBLIN    DISSECTOR.  357 

by  its  connexion  to  the  handle  of  the  malleus  ;  it  consists 
of  three  layers,  an  external  or  cuticular,  an  internal  or 
mucous,  and  a  middle  or  fibrous,  which  is  dry  and  elastic. 

[On  which  in  the  elephant,  Sir  E.  Home,  found  radiated  muscular 
fibres.] 

The  cavity  of  the  tympanum  may  be  seen  either  by  divid- 
ing the  membrane  just  described,  or  without  injuring  the 
latter,  the  roof  of  the  cavity  may  be  broken  or  cut  through 
at  the  lower  and  internal  part  of  the  squamous  plate ;  this 
cavity  is  placed  between  the  meatus  externus  and  the  la- 
byrinth ;  it  is  of  an  irregular  figure,  rather  circular ;  it 
presents  on  its  internal  side  or  wall  a  tubercular  eminence, 
named  the  promontory,  and  two  foramina,  one  above,  the 
other  below  that  eminence  ;  the  superior  foramen,  orfenes- 
tra  ovalis,  is  closed  by  a  membrane,  to  which  the  base  of 
the  stapes  bone  is  attached,  this  opening  communicates 
with  the  vestibule;  the  inferior  or  the  foramen  rotundum  is 
also  closed  by  a  membrane,  it  communicates  with  the  in- 
ternal part  of  the  cochlea  or  the  scala  tympani ;  the  pos- 
terior wall  of  the  tympanum  presents  superiorly  the  open- 
ing of  a  short  canal,  which  leads  to  the  mastoid  cells,  in 
this  opening  the  short  leg  of  the  incus  rests ;  these  cells  are 
of  irregular  form  and  differ  in  different  subjects ;  beneath 
this  is  the  pyramid,  a  small  bony  projection,  hollow,  con- 
taining the  muscle  of  the  stapes ;  beneath  the  pyramid  is 
the  small  foramen  leading  from  the  aqueduct  of  Fallopius, 
and  transmitting  the  corda  tympani.  The  tympanum  pre- 
sents anteriorly  the  openings  of  two  canals,  one  superior 
containing  the  tensor  tympani  muscle,  the  other,  the  infe- 
rior, is  the  Eustachian  tube;  this  descends  obliquely  for- 
wards and  inwards,  and  terminates  by  a  trumpet-shaped 
mouth,  behind  the  posterior  nares,  on  a  level  with  the  infe- 
rior spongy  bone ;  this  canal  is  small,  and  osseous  poste- 
riorly, anteriorly  it  is  large  and  formed  of  membrane  ex- 
ternally, and  of  a  curved  fibro-cartilage  internally. 

[It  runs  for  six  or  eight  lines  in  the  petrous  portion  of  the  temporal 
bone,  its  entire  length  being  about  two  inches,  and  its  diameter  a 
line  and  a  half.] 

It  is  lined  by  mucous  membrane,  which  is  prolonged  from 
the  pharynx  into  the  tympanum ;  through  this  tube  the  at- 
mosphere can  pass  from  the  fauces  into  the  tympanum,  to 
support  the  latter  on  its  internal  surfaces  In  the  superior 
boundary  or  wall  of  the  tympanum  are  some  small  fora- 
mina for  the  passage  of  blood-vessels ;  its  inferior  boun- 
dary presents  the  glenoid  fissure,  through  which  pass  the 
corda  tympani,  the  tendon  of  the  laxator  tympani,  and  the 
processus  gracilis  of  the  malleus.  Within  the  cavity  of 


358  DUBLIN    DISSECTOR. 

the  tympanum  are  four  small  bones,  first  the  malleus,  at- 
tached to  the  membrana  tympani,  and  resting  on  the  se- 
cond, the  incus,  one  leg  of  which  is  connected  to  the  third, 
the  orbicular,  which  is  articulated  to  the  fourth,  the  stapes, 
which  rests  on  the  membrane  of  the  fenestra  ovalis,  be* 
tween  which  and  the  membrana  tympani  these  bones  form 
a  connecting  chain  or  spring,  for  the  purpose  of  conveying 
the  impressions  of  sound  from  the  membrana  tympani  to 
the  internal  ear.  The  malleus  is  immediately  behind  the 
membrana  tympani,  it  presents  a  head,  neck,  handle,  a  long 
and  short  process ;  the  head  is  smooth  and  articulated  be- 
hind with  the  incus,  the  neck  is  small,  and  gives  origin  an- 
teriorly to  the  processus  gracilis,  which  is  about  half  an 
inch  long,  traverses  the  glenoid  fissure,  and  gives  attach- 
ment to  the  tendon  of  the  laxator  tympani  muscle;  the 
handle  descends  from  the  neck,  adheres  to  the  membrana 
tympani,  and  has  a  short  process  superiorly  for  the  inser- 
tion of  the  tensor  tympani  muscle.  The  incus  is  internal 
and  posterior  to  the  malleus,  presents  a  body,  and  a  long 
and  short  crus ;  the  body  is  directed  forwards  and  upwards, 
and  receives  the  head  of  the  malleus,  the  superior  crus  is 
short,  and  lies  in  the  foramen  of  the  mastoid  cells,  the  in- 
ferior long,  and  perpendicular,  is  articulated  with  the  fol- 
lowing ; — The  os  orbiculare,  extremely  small,  is  between  the 
incus  and  the  following  bone. 

[In  the  adult  subject  it  is  very  frequently  fused  into  the  incus,  this 
sometimes  occurs  even  in  children.] 

The  stapes  is  placed  horizontally,  the  base  is  on  the  fe- 
nestra ovalis,  the  head  is  articulated  to  the  orbicular  bone, 
the  neck  gives  attachment  to  the  stapedius  muscle,  the 
crura  of  the  stirrup  are  separated  by  a  space  filled  by 
membrane. 

[There  is  a  diarthrodial  joint  between  the  malleus  and  incus ;  but 
the  other  bones  are  connected  by  ligamentous  tissue  only.] 

There  are  three  muscles  in  the  tympanum,  viz.  stapedius, 
tensor,  and  laxator  tympani.  Stapedius  arises  within  the 
pyramid ;  its  tendon  is  inserted  into  the  neck  of  the  stapes  ; 
its  use  is  to  raise  the  stapes,  and  to  press  its  base  against  the 
fenestra  ovalis.  Tensor  tympani  arises  in  the  canal  in  the 
petrous  bone  above  the  Eustachian  tube,  passes  backwards 
into  the  tympanum,  and  is  inserted  into  the  short  process 
below  the  neck  of  the  malleus ;  use  to  draw  the  malleus 
into  the  tympanum,  and  thus  to  increase  the  concavity  of 
the  membrana  tympani.  Laxator  tympani  arises  from  the 
spinous  process  of  the  sphenoid  bone,  and  from  the  Eusta- 
chian tube,  ends  in  a  delicate  tendon  which  passes  through 
the  glenoid  fissure  along  with  the  corda  tympani,  and  is  in- 


DUBLIN    DISSECTOR.  359 

serted  into  the  processus  gracilis  of  the  malleus  or  the  pro- 
cess of  Raw.  Use,  to  draw  the  malleus  forwards,  and  thus 
to  relax  the  membra na  tympani. 

The  labyrinth,  or  the  internal  ear,  consists  of  the  vestibu- 
lum,  cochlea,  semicircular  canals,  and  meatus  internus,  the 
cochlea  is  anterior,  the  canals  are  posterior.  Vestibulum  is 
a  small  elliptical  cavity  behind  the  cochlea  and  in  front  of 
the  semicircular  canals,  the  fenestra  ovalis  opens  on  its  ex- 
ternal side,  the  five  orifices  of  the  semicircular  canals  open 
superiorly  and  posteriorly,  one  opening  from  the  cochlea  is 
anteriorly,  and  posteriorly  is  the  orifice  of  a  small  canal 
called  the  aqueduct  of  the  vestibule,  which  opens  on  the 
posterior  surface  of  the  petrous  bone,  in  a  small  cavity 
lined  by  dura  mater,  behind  the  meatus  auditorius  internus, 
and  thus  forms  a  communication  between  this  cavity  and 
the  base  of  the  cranium.  A  delicate  but  vascular  mem- 
brane lines  this  cavity  ;  it  is  filled  by  a  peculiar  fluid,  and 
extends  into  the  aqueduct  of  the  vestibule.  The  semicircu- 
lar canals  are  three  in  number,  superior,  posterior,  and  ho- 
rizontal ;  the  two  first  are  vertical. 

[Their  diameter  internally  is  half  a  line  and  that  extremity  of  each, 
which  is  nearest  the  foramina  ovale  and  rotundum,  is  enlarged,  so  as 
to  constitute  what  is  called  the  ampulla.] 

They  are  surrounded  by  the  petrous  bone  in  front  of  the 
mastoid  cells  and  behind  the  vestibule ;  the  superior  and 
posterior  are  joined  by  one  end ;  there  are,  therefore,  but 
five  orifices  of  these  canals  in  the  vestibule  ;  each  of  these 
tubes  is  lined  by  a  vascular  membrane  filled  with  a  fluid 
which  communicates  with  that  in  the  vestibule.  The  coch- 
lea is  in  the  anterior  part  of  the  petrous  bone,  is  is  some- 
what conical,  the  base  towards  the  meatus  internus,  the 
apex  towards  the  carotid  artery  ;  the  cochlea,  internally, 
consists  of  a  central  pillar  placed  somewhat  horizontally, 
named  the  modiolus,  and  of  a  spiral  tube  passing  round 
this  axis,  two  turns  and  a  half;  this  tube  is  divided  into  two 
by  a  thin  osseous  and  membranous  plate,  called  lamina 
spiralis,  and  the  two  tubes  are  the  scala?  of  the  cochlea ; 
near  the  apex  of  the  cochlea  these  scala3  communicate; 
near  the  base  they  separate ;  one,  the  scala  vestibuli,  com- 
municates with  the  vestibule;  the  other,  the  scala  tympani, 
with  the  tympanum  through  the  fenestra  rotunda  ;  the  mo- 
diolus is  hollow  and  expanded  towards  the  apex ;  this  ex- 
pansion is  called  the  infundibulum  ;  a  branch  of  the  audi- 
tory nerve  passes  through  this  cavity  ;  the  aqueduct  of  the 
cochlea  terminates  in  a  small  slit-like  opening  on  the  infe- 
rior surface  of  the  petrous  bone,  just  before  the  foramen 
lacerum  posterius.  The  portio  mollis  of  the  seventh  pair  of 
nerves  descends  along  the  meatus  auditorius  internus,  di- 


360  DUBLIN    DISSECTOR. 

vides  into  several  fine  branches,  which  are  distributed  to 
the  membrane  lining  the  vestibule,  cochlea,  and  semicircu- 
lar canals. 

[The  external  ear  is  sometimes  entirely  wanting,  sometimes  the 
lobule  alone  is  wanting,  or  it  may  exist,  but  adhere  to  the  side  of  the 
head  ;  the  auditory  canal  is  sometimes  imperforate,  sometimes  ob 
structed  by  morbid  growths,  of  which  the  polypus  is  most  common. 
The  membrane  tympani  is  the  seat  of  acute  and  chronic  inflamma- 
tion, which  may  go  on  to  suppuration,  ulceration,  and  the  discharge 
of  the  bones  of  the  ear,  causing  incurable  deafness  ;  these  bones  are 
sometimes  wanting  at  birth.  The  custachian  tube  is  liable  to  congeni- 
tal imperforation,  or  to  accidental  obstruction  from  various  causes, 
the  result  is  deafness,  more  or  less  complete.  An  instrument  has 
been  introduced  into  the  pharyngeal  extremity  of  this  tube,  for  the 
purpose  of  clearing  away  obstructions  ;  or  to  act  on  the  principle  of 
a  bougie,  dilating  the  passage,  and  thus  curing  deafness,  by  admit- 
ting air  to  the  internal  ear.  Deafness  is  often  caused,  particularly  in 
elderly  persons,  by  an  accumulation  of  wax  upon  the  outer  surface  of 
the  membrana  tympani,  and  filling  up  the  external  passage.  This 
is  to  be  relieved  by  throwing  in  oil  or  tepid  water  so  as  to  soften  the 
wax,  after  which  it  may  be  readily  removed. 

The  nerves  of  the  ear  are  the  auditory  or  portio  mollis,  the  facial 
or  portio  dura,  and  the  chorda  tympani.  The  arteries  of  the  ear, 
both  external  and  internal,  are  derived  principally  from  the  posterior 
auricular,  internal  maxillary,  and  temporal  branches,  of  the  external 
carotid.] 


SECTION  IV. 

ANATOMY    OF    THE    EYE. 

UNDER  this  head  we  shall  examine  not  only  the  globe  of 
the  eye  but  its  appendages ;  these  are  the  eyelids,  the  lach- 
rymal apparatus,  and  the  muscles  of  the  orbit :  we  shall 
commence  with  the  latter. 

The  muscles  of  the  orbit  are  seven  in  number,  viz.  the 
levator  palpebrae  superioris,  the  obliquus  superior  and  in- 
ferior, and  the  four  recti ;  to  obtain  a  satisfactory  view  of 
these  muscles,  the  roof  and  a  considerable  portion  of  the 
external  side  of  the  orbit  must  be  removed ;  then  the  peri- 
osteum having  been  divided,  the  first  muscle  appears. 

[The  muscles  which  act  upon  the  eye  and  its  appendages,  are  eleven 
in  number,  and  may  be  arranged  in  two  groups,  the  one  acting  upon 
the  appendages,  and  formed  by  five  muscles,  the  other  acting  upon 
the  ball  of  the  eye  itself,  and  formed  by  six  muscles. 


DUBLIN    DISSECTOR.  361 

First  Group,  five  Muscles. 
Occipito  Frontalis, 
Corrugator  Supercilii, 

Levator  Palpebrse  Superioris,   }•  Vide  p.  361. 

Orbicularis  Palpebrarurn, 
Tensor  Tarsi, 

Second  Group,  six  Muscles. 

Superior  Rectus,  or  Levator  Oculi,     } 

Inferior  Rectus,  or  Depressor  Oculi,    ( 

Internal  Rectus,  or  Adductor  Oculi,  f 

External  Rectus,  or  Abductor  Oculi,  ) 

Obliquus  Superior,  ) 

Obliqu us  Inferior,    \ 

The  muscles  of  the  first  group  are  situated  on  the  head,  face,  and 
in  part,  in  the  orbit :  those  of  the  second  group  are  entirely  within 
the  orbit.] 

LEVATOR  PALPEBRSE  SUPERIORIS  is  the  highest  and  longest 
muscle  in  the  orbit ;  it  arises  narrow  and  tendinous  from 
the  upper  edge  of  the  foramen  opticum,  passes  forwards  and 
outwards  beneath  the  frontal  nerve,  and  becoming  broader, 
aends  down  in  front  of  the  eye ;  it  then  ends  in  a  dense 
cellular  expansion  which  is  inserted  into  the  superior  border 
of  the  tarsal  cartilage  and  into  the  superior  pal pebral  sinus 
of  the  conjunctiva  behind  the  palpebral  ligament.  Use,  to 
elevate  and  retract  into  the  orbit  the  upper  eyelid. 

OBLIQUUS  SUPERIOR,  at  the  upper  and  inner  part  of  the 
orbit,  arises  on  the  inner  side  of  the  preceding,  passes  for- 
wards along  the  os  planum,  ends  in  a  round  tendon  which 
plays  through  the  fibre-cartilaginous  pulley  which  is  at- 
tached to  the  inner  angle  of  the  os  frontis  ;  this  tendon  is 
then  reflected  backwards,  outwards,  and  downwards,  be- 
tween the  superior  rectus  and  the  eye,  and  then  becoming 
broad  and  thin,  is  inserted  into  the  sclerotic  coat  between  the 
superior  and  external  recti,  about  midway  between  the  en- 
trance of  the  nerve  and  the  insertion  of  the  superior  rec- 
tus. Use,  to  draw  the  eye  forwards  and  inwards,  also  to 
rotate  it,  so  as  to  direct  the  cornea  downwards,  and  accord- 
ing to  some,  inwards  towards  the  tip  of  the  nose :  other  au- 
thors consider  it  a  rotator  outwards. 

OBLIQUUS  INFERIOR  is  situated  at  the  inferior  and  anterior 
part  of  the  orbit ;  it  arises  tendinous  from  the  orbital  edge 
of  the  superior  maxillary  bone  above  the  infra-orbital  fo- 
ramen, and  external  to  the  lachrymal  sac ;  it  ascends  ob- 
liquely outwards  and  backwards  below  the  inferior  rectus, 
and  is  inserted  by  a  tendinous  expansion  into  the  sclerotic 
coat  behind  the  transverse  axis  of  the  eye,  and  between  the 
sclerotic  coat  and  the  external  rectus.  Use,  to  draw  the 
globe  forwards  and  inwards,  and  to  rotate  it  upwards  and 
31 


362  DUBLIN    DISSECTOR. 

outwards :  the  rotatory  powers  of  the  oblique  muscles  arc 
involved  in  some  obscurity,  but  no  doubt  exists  as  to  their 
principal  use,  that  of  drawing  forward  the  globe,  so  as  to 
oppose  the  retracting  influence  of  the  recti. 

Recti  muscles  are  four  in  number,  the  superior  is  called 
attollens  oculi,  the  inferior  depressor  oculi,  the  internal  adduc- 
tor, and  the  external  abductor  oculi :  they  all  arise  from  the 
periosteum  around  the  optic  foramen  ;  the  external  has  an 
additional  attachment  to  the  foramen  lacerum  ;  they  all 
pass  forwards  around  the  optic  nerve,  separated  from  it  by 
the  ciliary  vessels  and  nerves,  and  by  a  great  quantity  of 
fat ;  a  little  beyond  the  middle  of  the  eye  they  become  ten- 
dinous, and  are  each  inserted  [into  the  sclerotic  coat,]  about  a 
quarter  of  an  inch  behind  the  cornea  ;  the  four  tendons  are 
connected  together  by  an  aponeurosis  which  is  attached  to 
the  conjunctiva  ;  the  use  of  these  muscles  is,  collectively,  to 
retract  the  eye  into  the  orbit,  and  individually  to  move  it, 
as  their  names  imply. 

Under  the  head  of  lachrymal  apparatus  we  may  consi- 
der the  lachrymal  gland,  membrana  conjunctiva,  palpebrae, 
and  lachrymal  passages.  The  lachrymal  gland  is  placed  in 
the  upper  part  of  the  orbit,  behind  the  external  angular 
process  of  the  os  frontis,  above  the  external  rectus  and  the 
conjunctiva  ;  of  a  flattened  oval  figure. 

[It  is  of  a  light  pink  color  ;  it  is  convex  above,  concave  below,  and 
measures  in  length  about  ten  lines,  in  breadth  six  lines,  and  at  its 
thickest  part  two  lines.] 

It  is  separable  into  two  or  more  lobes,  which,  like  other 
conglomerate  glands,  can  be  separated  into  numerous  gra- 
nules ;  these  are  united  by  a  loose  capsule  ;  from  these,  five 
or  six  small  ducts  proceed  and  open  behind  the  upper  eye- 
lid along  the  line  of  reflection  of  the  conjunctiva  from  the 
palpebra  to  the  sclerotic. 

The  Membrana  Conjunctiva  is  a  mucous  membrane  lining 
each  palpebra,  and  continuous  at  their  margins  with  the  in- 
teguments, it  also  covers  the  anterior  part  of  the  globe ; 
near  the  inner  canthus  it  is  thrown  into  a  semilunar  fold, 
[the plica  semilunaris,]  and  is  continued  through  the  puncta 
lachrymalia  into  the  nasal  sac  and  duct,  and  becomes  con- 
tinous  with  the  mucous  membrane  of  the  nose.  This 
membrane  is  more  vascular  on  the  palpebrasandcaruncula 
than  on  the  surface  of  the  eye  ;  it  is  loosely  connected  to 
the  sclerotic  coat  to  within  half  an  inch  of  the  cornea,  it 
then  becomes  so  delicate  and  so  adherent  that  it.  is  difficult 
to  separate  it  further,  and  although  it  is  generally  described 
as  being  continued  over  the  cornea,  it  is  impossible  to  dis- 
sect it  from  it  unless  previously  macerated  or  changed  by 


DUBLIN    DISSECTOR.  363 

disease  ;  at  the  inner  canthus  of  the  orbit  it  is  thrown  for- 
wards by  a  fleshy  looking  tubercle  of  a  conical  figure,  the 
caruncuia  lachrymalis,  this  is  composed  of  a  few  mucous  fol- 
licles and  the  bulbs  of  some  fine  hairs  that  project  from  its 
surface.  The  conjunctiva  is  a  secreting,  and  according  to 
some,  an  absorbing  surface  ;  it  is  constantly  moistened  by 
the  fluid  it  secretes,  and  occasionally  by  the  lachrymal  se- 
cretion ;  it  serves,  as  its  name  implies,  to  join  the  eyelids  to 
the  eye,  to  facilitate  the  motions  of  the  former,  and  thereby 
to  clear  the  surface  of  the  latter ;  it  also  closes  the  orbit 
against  any  extraneous  substance,  and  serves  to  support 
and  confine  the  eyeball  in  its  several  motions. 

Palpebrcc.  are  composed  of  the  skin,  the  orbicular  muscle, 
a  thin  cartilage  connected  to  the  base  of  the  orbit  by  a  cel- 
lulo-ligamentous  connexion,  and  lined  by  conjunctiva ;  in 
the  superior  there  is  also  the  expansion  of  the  levator  pal- 
pebrse  muscle;  the  upper  is  larger  than  the  lower  eyelid, 
therefore,  when  they  are  closed  the  former  descends  below 
the  transverse  axis  of  the  eye,  and  the  inferior  ascends  but 
little  to  meet  it ;  they  are  both  concave  posteriorly,  adapt- 
ed to  the  surface  of  the  eye,  their  margins  are  thick,  and 
furnished  anteriorly  with  the  eyelashes,  posteriorly  with 
numerous  mucous  follicles  ;  their  opposed  edges  are  sloped 
off  obliquely  towards  the  eye,  so  that  when  the  lids  are 
closed  a  sort  of  triangular  canal  is  formed,  the  base  of 
which  is  the  surface  of  the  eye ;  along  this  canal  the  tears 
are  supposed  by  some  to  be  directed  inwards  towards  the 
puncta,  others,  however,  deny  that  any  such  space  can  ex- 
ist, and  affirm  that  the  lachrymal  secretion  flows  along 
each  palpebral  sinus,  and  is  directed  inwards  by  the  action 
of  the  orbicular  muscle  ;  the  skin  of  each  palpebra  is  thin, 
the  sub-cutaneous  cellular  tissue  very  loose  and  reticular  ; 
beneath  this  the  orbicular  muscle  is  expanded.  (See  p.  6.) 

[The  meeting  of  the  palpebra?  externally  and  internally,  forms  the 
angles  or  canthi,  which  are  connected  to  the  adjacent  margins  of  the 
orbit  by  the  external  and  internal  palpebral  ligaments,  the  latter  of 
which  is  nearly  half  an  inch  long,  and  is  made  tense  by  drawing  the 
lids  outwards  ;  it  is  the  guide  for  the  incision  in  the  operation  for  fis- 
tula lachrymalis.] 

The  tarsdl  cartilages  are  thin  elastic  plates ;  the  superior 
is  semikmar  and  larger  than  the  inferior  which  is  long, 
narrow  and  nearly  straight. 

[The  superior  tarsus  is  six  lines  broad  at  its  widest  part,  the  centre  ; 
the  inferior  is  nearly  uniformly  two  lines  wide.  These  cartilages  are 
of  use  in  preserving  the  form  of  the  lids,  and  oppose  the  orbicularis 
muscle,  which  would  otherwise  pucker  up  the  lids  like  the  mouth  of 
a  bag, when  closed  by  a  drawing  string.] 

The  ciliary  margins  are  thick ;  their  orbital  edges  thin 


364  DUBLIN    DISSECTOR. 

and  connected  to  the  orbit  by  the  palpebral  ligaments 
which  are  a  continuation  of  the  periosteum;  these  liga- 
ments are  stronger  towards  the  temple,  where  they  decus- 
sate and  attach  the  cartilages  at  their  external  canthus  or 
commissure ;  the  tendo  oculi  [or  internal  palpebral  liga- 
ment] fixes  them  internally.  Between  each  tarsal  carti- 
lage and  the  conjunctiva  are  the  Meibomian  glands  or  folli- 
cles; these  are  of  a  white  or  yellow  colour,  are  arranged  in 
nearly  parallel  vertical  rows,  and  are  more  numerous  in 
the  upper  eyelid ;  they  secrete  a  thin  sebaceous  fluid, 
which  is  discharged  by  a  row  of  small  holes  along  the  edge 
of  each  tarsus  behind  the  cilia.  The  cilia  arise  from  bulbs 
which  are  beneath  the  skin  ;  those  of  the  upper  eyelid  are 
more  numerous  than  those  in  the  lower;  both  are  curved, 
convex  towards  each  other. 

[Overhanging  the  eye  and  placed  upon  the  projection  formed  by 
the  os  fronlis,  are  those  hairs  called  the  super  cilia  or  eye-brows,  sepa- 
rated from  each  other  usually  in  the  median  line,  by  a  bare  space  the 
glabella.] 

The  Puncta  Lachrymalia  are  two  small  holes  always 
open,  directed  backwards  and  outwards,  opposite  each 
other ;  they  meet  when  the  lids  are  closed ;  each  is  situated 
in  a  little  cartilaginous  projection,  about  two  lines  from 
the  inner  canthus ;  each  is  the  orifice  of  the  small  lachry- 
mal duct. 

[Each  is  a  line  in  depth  and  meets  the  duct  at  a  right  angle,  so  that  in 
introducing  a  probe,  it  is  to  enter  the  punctum  vertically,  then  it  is  to 
be  brought  to  a  right  angle  to  its  first  position,  and  carried  along  the 
duct  about  half  an  inch  ;  it  is  then  again  to  be  raised  nearly  parallel 
with  its  first  position,  after  which  it  may  be  carried  into  the  lachry- 
mal sac.] 

The  Lachrymal  duels  extend  from  the  puncta  to  the  lachry- 
mal sac. 

[They  are  half  an  inch  in  length  and  a  line  in  diameter.] 
The  superior  is  longer  and  more  curved  than  the  infe- 
rior; the  former  is  concave  inferiorly  ;  the  latter  is  nearly 
straight,  a  little  concave  upwards;  they  both  open  into  the 
external  part  of  the  sac  a  little  above  its  middle,  sometimes 
by  one  and  sometimes  by  distinct  orifices,  behind  the  ten- 
do  oculi ;  each  duct  is  surrounded  by  a  process  of  that 
tendon,  and  lined  by  mucous  membrane. 

[The  plica  semilunaris  is  a  valvular  fold  of  the  conjunctiva,  at  the 
angle  of  the  eye  and  directly  external  to  the  caruncle,  it  is  triangular 
in  form,  the  apex  being  internal,  and  base  external ;  its  base  is  some- 
times furnished  with  a  small  cartilage,  more  frequently  in  the  negro 
according  to  Homer.  The  use  of  this  fold,  in  the  human  subject, 
appears  to  be  for  the  free  abduction  of  the  eye ;  it  is  &!BO  analagous 


DUBLIN    DISSECTOR.  365 

to  the  third  eyelid  of  animals;  in  which  the  third  eyelid,  is  in 
inverse  ratio  to  the  others,  until  as  we  descend  in  the  scale,  it  entirely 
supplies  their  place.] 

The  Lachrymal  sac  is  a  small  oval  pouch  of  mucous  mem- 
brane, closed  above  and  leading  below  into  the  nasal  duct,  it 
is  situated  in  a  fossa  formed  by  the  maxillary  and  unguis 
bones,  covered  by  the  skin,  the  tendo  oculi,and  some  fleshy 
fibres  of  the  orbicularis  muscle,  also  by  a  strong  fascia 
which  is  derived  from  that  tendon  and  connected  to  the 
surrounding  bony  margin.  A  small  muscle  has  been  de- 
scribed by  Mr.  Homer  as  arising  from  the  edge  of  the  os 
unguis,  and  inserted  into  the  lachrymal  sac  and  ducts ;  he 
conceives  it  to  have  the  power  of  compressing  the  sac,  and 
directing  the  ducts  and  their  contents  towards  it ;  it  is  not, 
however,  in  all  subjects  to  be  distinguished  from  the  orbi- 
cular, which  last  can  effect  these  purposes. 

The  Nasal  duct  (about  three-fourths  of  an  inch  in  length 
in  the  recent  state)  descends  from  the  sack  obliquely  back- 
wards and  a  little  outwards,  surrounded  by  the  maxillary, 
unguis,  and  inferior  spongy  bones  ;  beneath  the  latter  it 
opens  by  a  small  slit-like  orifice,  which  is  surrounded  by 
a  circular  fold  of  mucous  membrane  which  is  sometimes 
so  loose  as  to  appear  as  a  valve,  into  the  lower  meatus, 
about  an  inch  from  the  anterior  part  of  the  naris;  this  duct 
is  formed  of  mucous  membrane  only,  and  which  is  closely 
connected  to  the  periosteum.  The  nerves  and  vessels  of  the 
orbit  have  been  already  examined.  The  nerves  of  the  pal- 
pebrse  are  derived  from  the  portio  dura  of  the  seventh, 
from  the  lachrymal,  frontal,  and  nasal  branches  of  the  oph- 
thalmic, and  from  the  infra-orbital  branches  of  the  fifth 
pair  of  nerves  :  the  vessels  are  branches  of  the  ophthalmic, 
temporal,  and  facial. 

DISSECTION    OF    THE    GLOBE    OF    THE    EYE. 

[The  organs  forming  the  ball  of  the  eye,  may  be  conveniently 
grouped  as  follows  ;  fi;st,  thrtjc  concentric  lamina?,  the  sclerotic  coat, 
choroid  coat,  and  the  retina  :  second,  two  vertical  organs,  or  mem- 
brant's,  the  cornea  and  the  iris:  tin  d.  three  humours,  the  aqueous 
humour,  the  crystallineltiiis,  or  humour,  and  the  vitreous  humour.} 

It  will  facilitate  the  student  in  learning  the  anatomy  of 
the  eye,  to  dissect  this  organ  in  some  of  the  inferior  ani- 
mals; almost  every  part  of  importance  may  be  examined 
with  equal  advantage  in  the  eye  of  the  sheep,  ox,  or  pig, 
as  in  that  of  the  human  subject ;  many  of  the  minute  parts 
are  even  on  a  larger  scale,  and  can  be  dissected  with  great- 
er ease  :  we  also  have  it  in  our  power  in  general  to  dissect 
the  eyes  of  the  inferior  animals  in  a  perfectly  fresh  state. 

The  eye  is  situated  at  the  anterior  and  internal  part  of 
31* 


366  DUBLIN    DISSECTOR, 

the  orbit,  behind  the  conjunctiva,  surrounded  by  muscles 
and  fat,  and  connected  posteriorly  by  the  optic  nerve  ;  the 
axes  of  the  eyes  are  parallel  to  each  other,  therefore  not 
so  to  those  of  the  orbits;  each  eye  is  nearly  spherical ;  the 
antero-posterior  axis,  which  is  nearly  an  inch,  being  about 
one  or  two  lines  greater  than  the  transverse  or  vertical 
axis;  the  cornea,  which  is  a  segment  of  a  smaller  sphere, 
and  which  forms  about  the  anterior  fifth  of  the  globe,  being 
superadded  to  the  larger  sphere,  formed  by  the  sclerotic ; 
this  spherical  form  favours  the  motion  of  the  eyeball.  The 
eye  is  composed  of  fluids  or  humours  enclosed  in  different 
tunics,  the  latter  are  the  sclerotic,  choroid  and  retina,  the 
first  is  a  fibrous,  the  second  a  vascular  and  the  third  a 
nervous  coat ;  the  humours  are  the  aqueous,  crystalline 
and  vitreous  ;  these  are  also  enclosed  in  distinct  capsules. 

TUNICA  SCLEROTICA  is  a  dense,  opaque,  fibrous  membrane, 
extending  from  the  optic  nerve  to  the  cornea ;  the  nerve 
perforates  it  about  a  line  internal  to  its  centre  by  a  small 
conical  aperture,  which  appears  traversed  by  fibres,  so  as 
to  present  a  cribriform  appearance  ;  it  is  doubtful,  how- 
ever, whether  this  indistinct  appearance  may  not  partly 
depend  on  the  central  vein  and  artery  of  the  retina  which 
accompany  the  nerve  through  this  opening;  the  sheath  of 
the  optic  nerve  is  continuous  with  the  fibres  of  this  mem- 
brane; the  external  surface  of  the  sclerotic  is  rough  and 
perforated  by  several  holes ;  anteriorly  it  receives  the  cor- 
nea, and  is  so  intimately  connected  to  it,  that  maceration 
alone  can  separate  them ;  both  are  sloped  off  obliquely  as 
well  as  slightly  grooved;  the  sclerotic  overlaps  the  cornea. 

[This  is  sometimes  the  case,  but  at  other  times  the  cornea  overlaps 
the  sclerotic,  and  in  other  cases  the  margin  of  (he  sclerotic  is  grooved, 
and  the  edge  of  the  cornea  is  received  into  the  groove,  like  the  crys. 
tal  of  a  watch  inserted  into  the  rim.] 

Their  connexion  is  still  further  secured  by  the  conjunc- 
tiva externally,  and  by  the  membrane  of  the  aqueous  hu- 
mour internally ;  a  vertical  section  of  this  tunic  from  be- 
hind forwards  will  shew  its  great  thickness  near  the  optic 
nerve,  and  its  thinness  in  the  centre  [being  one  line  thick 
in  the  former  situation,  and  half  a  line  in  the  latter;]  ante- 
riorly it  is  again  strengthened  by  the  tendinous  expansion 
of  the  recti  muscles  ;  this  expansion  has  been  improperly 
called  the  tunica  albuginea ;  the  sclerotic  consists  of  fibres 
which  run  in  every  direction,  but  which  do  not  form  dis- 
tinct laminae ;  its  internal  surface  is  smooth  and  glisten- 
ing;  the  ciliary  vessels  and  nerves  run  between  it  and  the 
choroid;  from  this  surface  a  fine  serous-like  lamina  may 
be  raised ;  this  is  reflected  on  the  choroid  coat. 


DUBLIN    DISSECTOR.  367 

The  cornea  forms  the  anterior  fifth  of  the  eye ;  it  is  near- 
ly circular,  its  transverse  diameter  being  a  little  greater 
than  its  vertical ;  it  is  very  smooth  and  transparent,  of  a 
laminated,  not  a  fibrous  texture;  some  fine  cellular  tissue 
connects  the  laminae  to  each  other ;  the  cornea  is  more 
thick  and  pulpy  in  the  child  than  in  the  adult;  it  is  cover- 
ed anteriorly  by  a  fine  and  closely  adhering  membrane, 
which  though  generally  considered  a  continuation  of  the 
conjunctiva,  is  very  different  from  it  in  its  structure  and 
properties. 

[That  this  membrane  is  continuous  with  the  conjunctiva,  is  proved 
by  the  fact  that  it  comes  off  with  the  conjunctiva  and  epidermis  of 
those  animals  which  shed  their  skin,  as  the  locust,  snake,  &,c.  The 
lining  membrane  of  the  stomach  and  that  of  the  uterus  are  different 
in  their  appearance,  and  in  their  secretion,  yet  both  are  considered  as 
belonging  to  the  mucous  tissue.] 

The  concave  surface  of  the  cornea  is  lined  by  a  fine  elas- 
tic membrane,  which  is  described  by  some  as  a  part  of  the 
membrane  of  the  aqueous  humour ;  it  is,  however,  a  mem- 
brane sui  generis ;  it  is  best  seen  in  the  eye  of  a  horse, 
which  has  been  macerated  for  some  days,  the  external  la- 
minse,  which  are  now  opaque,  can  be  peeled  off,  leaving 
behind  it  this  elastic  cornea,  which  preserves  its  proper 
curve  and  transparency ;  if  it  be  cut  it  will  curl  upon  itself, 
thus  exhibiting  true  elastic  cartilaginous  properties.  Fix 
the  eye  in  a  small  shallow  vessel,  which  can  be  immersed 
occasionally  under  water,  carefully  raise  a  small  portion  of 
the  sclerotic,  pass  in  some  air  between  it  and  the  choroid, 
these  membranes  can  thus  be  easily  separated  ;  then  dissect 
off  the  sclerotic,  this  tunic  can  be  readily  detached  as  far 
as  the  cornea,  here  it  adheres  to  the  ciliary  ligament;  this 
connexion  may  be  separated  with  the  handle'of  the  knife, 
the  cornea,  or  one-half  of  it,  may  also  be  removed  with  the 
sclerotic  and  the  next  tunic  of  the  eye  will  be  exposed,  the 
choroid,  with  its  appendages,  the  ciliary  ligament,  ciliary 
processes,  and  iris. 

The  Choroid  coat  extends  from  the  optic  nerve  all  round 
the  eye,  between  the  sclerotic  and  retina,  as  far  as  the  cili- 
ary ligament,  where  it  appears  on  the  external  surface  to 
terminate,  but  when  a  portion  of  it  is  raised,  its  internal 
surface  will  be  found  to  extend  inwards,  in  the  form  of 
folds  or  processes,  termed  ciliary,  to  be  examined  presently ; 
the  external  surface  of  the  choroid  is  smooth,  and  loosely 
connected  to  the  sclerotic  by  the  ciliary  vessels  and  nerves, 
and  by  fine  cellular  tissue;  this  surface  is  generally  tinged 
by  the  pigment  which  transudes  through  it ;  on  this  layer 
of  the  choroid,  numerous  fine  vascular  ramifications  run- 
ning in  parallel  arches  may  be  observed,  these  are  con- 


368  DUBLIN    DISSECTOR. 

nected  chiefly  with  the  veins  and  are  termed  the  vasa  vor- 
ticosa :  raise  a  portion  of  the  choroid,  by  tearing  it  from 
the  retina  with  a  forceps ;  its  internal  surface  is  covered 
by  a  brown  pigment,  which  is  thicker  before  than  behind  ; 
for  a  small  distance  round  the  optic  nerve  it  is  deficient ; 
wash  off  this  pigment,  the  choroid  will  be  found,  if  previ- 
ously injected,  to  be  very  vascular  and  villous ;  this,  the 
internal  layer,  which  by  dissection  can  be  separated  from 
the  external,  is  termed  membrana  Ruyschiana ;  the  ciliary  ar- 
teries supply  this  coat  with  blood,  for  the  purpose  of  se- 
creting the  pigment,  which  has  the  effect  of  absorbing  all 
rays  of  light  which  strike  the  sides  of  the  retina  ;  the  optic 
nerve  passes  through  a  round  opening  in  this  membrane, 
the  edges  of  which  are  not  connected  to  the  nerve ;  this 
tunic  is  more  dense  anteriorly  than  posteriorly. 

The  Ciliary  Ligament  corresponds  to  the  junction  of  the 
iris  to  the  choroid,  and  of  the  cornea  to  the  sclerotic ;  it 
forms  a  ring  of  grey  colour,  about  two  lines  broad,  of  a 
soft  and  cellular  texture,  and  has  some  resemblance  to  a 
nervous  ganglion. 

The  Ciliary  Processes  are  sixty  or  seventy  small  triangu- 
lar folds  of  the  choroid  coat,  which  are  arranged  in  a  ra- 
diated manner  around  the  lens  on  the  forepart  of  the  vi- 
treous humour,  each  extends  inwards  and  backwards  from 
the  ciliary  ligament  as  far  as  the  border  of  the  lens ;  each 
of  these  processes,  as  well  as  the  interstices  between  them, 
are  covered  by  the  pigmentum  nigrum,  the  term  corona  ci- 
liaris  is  applied  to  this  part ;  the  anterior  edge  of  each  pro- 
cess is  connected  to  the  ciliary  ligament  and  iris,  the  pos- 
terior to  the  vitreous  humour,  and  the  internal  is  loose,  and 
forms  the  circumference  of  the  posterior  chamber  of  the 
eye. 

The  Iris  is  a  delicate  circular  membrane,  floating  in  the 
aqueous  humour  and  suspended  vertically  behind  the  cor- 
nea, so  as  to  divide  the  space  between  this  and  the  lens  into 
two  chambers,  an  anterior  and  a  posterior,  the  former  is 
the  larger  of  the  two  ;  these  chambers  communicate  through 
the  central  aperture  in  the  iris,  the  pupil:  this  aperture  is  a 
little  nearer  its  nasal  than  its  temporal  side ;  the  external 
border  of  the  iris  is  fixed  to  the  ciliary  ligament,  its  poste- 
rior surface  is  also  in  part  attached  to  the  same  and  to  the 
ciliary  processes  ;  this  surface  is  covered  by  pigment,  and  is 
named  uxea ;  the  anterior  surface  is  covered  by  the  fine 
membrane  of  the  aqueous  humour,  and  streaked  with  dif- 
ferent coloured  lines,  some  of  which  take  a  radiated  course 
from  the  circumference  towards  the  pupil,  near  which  they 
cross,  divide,  and  unite  again,  and  appear  to  form  or  to  end 


DUBLIN    DISSECTOR.  369 

in  a  fasciculus  of  circular  fibres,  which  bound  the  pupil, 
and  which  are  of  a  darker  tint. 

[The  anterior  surface  of  the  iris,  is  said  to  exhibit,  one  of  two  colors, 
light  blue  or  orange,  and  the  particular  hue  of  the  eye  varies,  accord, 
ing,  as  one  or  the  other  of  these  two  colors  predominates,  and  is  corn, 
bined  with  the  darker  color  of  the  pigment,  on  the  posterior  surface 
of  the  organ.] 

The  iris,  when  examined  with  a  magnifying  glass,  has  a 
villous  appearance ;  when  the  pigment  is  washed  otf  the 
posterior  surface,  the  fibrous  structure  is  evident  there  also, 
and  bristles  may  even  be  passed  beneath  some  of  the  fasci- 
culi ;  the  iris  is  supplied  with  numerous  arteries  and  nerves ; 
the  former  are  branches  of  the  long  and  anterior  ciliary, 
the  latter  are  derived  from  the  lenticular  ganglion,  and 
from  the  nasal  nerve  ;  it  is  not  generally  agreed  on  wheth- 
er the  fibrous  appearance  of  the  iris  depends  on  the  pecu- 
liar arrangement  of  its  vessels  and  nerves,  or  whether  it 
possesses  a  true  muscular  structure ;  its  functions  may  lead 
one  to  incline  to  the  latter  opinion,  as  the  pupil  has  the 
power  of  contracting  rapidly  when  a  strong  light  ap- 
proaches the  eye,  and  of  again  dilating  when  the  light  is 
weak  ;  the  use,  therefore,  of  the  iris  is  to  regulate  the  quan- 
tity of  light  which  is  to  enter  the  eye.  The  pupil  is  closed 
in  the  foetus  by  a  delicate  but  vascular  membrane,  the 
membrana  pupillaris ;  this  membrane  is  ruptured  either  at, 
or  a  short  time  previous  to  birth. 

[This  membrane  does  not  disappear  until  some  days  after  birth  in 
certain  of  the  inferior  animals.] 

The  Retina  may  be  best  exposed  by  gently  tearing  off 
the  choroid,  (the  eye  being  held  under  water,)  and  then 
placing  an  inverted  glass  globe,  filled  with  clear  diluted 
spirits,  over  the  dissection  ;  the  retina  will  become  slight- 
ly opaque,  and  have  a  magnified  appearance.  The  optic 
nerve  having  pierced  the  choroid  coat  ends  in  this  thin  and 
delicate  membrane,  which  is  transparent  in  the  very  recent 
eye,  but  soon  becomes  opaque  after  death ;  the  retina  ex- 
tends around  the  sides  and  forepart  of  the  vitreous  humour 
without  adhering  to  it,  as  far  forwards  as  within  two  lines 
of  the  lens ;  here  the  nervous  matter  ends  by  an  abrupt 
line,  along  which  a  small  blood-vessel  runs.  The  retina 
is  divisible  into  three  layers :  first,  lamina  serosa  ;  second, 
lamina  nervosa;  and  third,  lamina  vasculosa.  The  exter- 
nal or  serous  layer  is  extremely  delicate,  it  may  be  separ- 
ated by  gentle  pressure  with  the  handle  of  the  knife  under 
water.  This  membrane  was  discovered  by  Dr.  Jacob.  The 
middle,  or  the  nervous  layer,  is  soft  and  grey,  and  continu- 
ous with  the  optic  nerve ;  the  internal  or  vascular  layer  is 


370  DUBLIN    DISSECTOR. 

very  delicate  ;  it  lies  on  the  vitreous  humour,  and  is  con- 
tinued on  its  forepart  to  the  capsule  of  the  lens,  where  it 
becomes  adherent  to  the  hyaloid  membrane.  Dissect  off 
the  posterior  half  of  the  retina  from  the  vitreous  humour, 
or  cut  transversely  a  fresh  eye,  and  allow  the  humours  to 
fall  out,  then  look  on  the  concave  surface  of  the  retina, 
and  we  may  observe  in  the  centre  of  the  optic  nerve  a  small 
dark  point,  the  poms  options ;  this  is  the  central  artery  of  the 
retina,  which  then  spreads  its  branches  in  the  internal  layer 
of  the  retina  ;  about  two  lines  external  to  this,  and  in  the 
axis  of  the  eye,  is  a  small  yellow  or  orange  spot,  the  punc- 
tum  aureum,  or  spot  of  Soemmerring ;  the  retina  is  thrown 
into  folds  around  this ;  some  describe  a  perforation  and  de- 
ficiency of  the  retina  at  this  spot,  it  rather  appears,  how- 
ever, to  depend  on  some  peculiar  organization.  The  hu- 
mours of  the  eye  are  the  aqueous,  cystalline,  and  vitreous. 
The  aqueous  humour  is  perfectly  colourless,  about  five 
grains  in  quantity  ;  it  fills  the  anterior  and  posterior  cham- 
bers, the  former  about  two  lines,  the  latter  about  half  a  line 
in  depth.  This  fluid  is  supposed  to  be  secreted  by  a  fine 
membrane,  which  is  continued  from  the  cornea  over  the 
iris,  and  through  its  pupillary  margin  to  its  posterior  sur- 
face ;  in  the  human  eye,  however,  it  is  impossible  to  trace 
any  such  membrane  through  this  extent.  This  fluid  sup- 
ports the  cornea  and  the  iris,  the  latter  can  float  and  move 
freely  in  a  fluid  of  such  thin  consistence. 

[This  fluid  is  readily  regenerated  after  having  been  lost,  as  in  the 
operation  for  cataract.] 

The  cystalline  humour  is  a  transparent  double  convex  lens, 
a  little  more  prominent  behind  than  before,  imbedded  in 
the  forepart  of  the  vitreous  humour  behind  the  anterior 
third  of  the  eye,  and  a  little  nearer  to  its  nasal  than  its 
temporal  side.  Its  axis  corresponds  to  that  of  the  pupil : 
it  is  surrounded  by  a  fine  capsule,  which  is  thin  and  soft 
posteriorly,  but  anteriorly  dense,  and  peculiarly  elastic ;  a 
small  quantity  of  fluid  (liquor  Morgagni)  is  contained  be- 
tween the  lens  and  its  capsule ;  the  lens  is  retained  in  its 
place  by  the  hyaloid  membrane,  which  splits  into  two  la- 
minse  at  its  border;  these  lamina  pass,  one  before,  the 
other  behind  it,  and  become  connected  to  the  proper  cap- 
sule ;  a  small  triangular  canal  (canal  of  Petit)  is  enclosed 
between  these  layers,  the  base  is  formed  by  the  circumfer- 
ence of  the  lens.  This  canal  is  intersected  by  fine  septa, 
it  therefore  presents  a  cellular  or  vesicular  appearance 
when  distended  by  air  or  injection.  Some  describe  this 
canal  as  formed  by  the  divison  of  the  lamina  vasculosa 
into  two  layers.  The  lens  is  soft  and  pulpy  extcrnallv. 


DUBLIN    DISSECTOR.  371 

more  dense  towards  the  centre,  or  a  little  internal  to  that 
point ;  maceration  or  boiling  causes  it  to  separate  into 
wedge  or  triangular  shaped  pieces,  the  apices  towards  the 
centre  ;  each  piece  appears  composed  of  successive  plates, 
and  each  plate  has  a  fibrous  structure.  In  the  foetus  the 
lens  is  reddish  and  very  soft ;  in  the  adult  it  is  transparent, 
and  in  the  old  it  has  an  amber  or  yellowish  cast  towards 
the  centre :  the  capsule  of  the  crystalline  lens  receives 
some  fine  vessels  from  the  central  artery  of  the  retina. 
The  lens  refracts  the  rays  of  light,  and  causes  them  to 
converge  to  a  focus  on  the  retina. 

The  vitreous  humour  fills  the  two  posterior  thirds  of  the 
globe  of  the  eye,  it  is  thin  and  almost  watery,  but  being 
enclosed  in  a  fine  membrane,  it  has  a  gelatinous  consis- 
tence ;  this  membrane  is  called  hyaloid,  it  encloses  the  fluid, 
and  sends  processes  into  it,  so  as  to  divide  the  whole  mass 
into  numerous  cells,  which  communicate  so  freely  that  air 
injected  will  rapidly  distend  them  ;  or  if  one  or  two  open- 
ings be  made  in  this  capsule,  the  whole  of  the  fluid  will 
gradually  escape ;  anteriorly  the  crystalline  lens  is  con- 
nected to  this  humour  by  the  hyaloid  membrane  separating 
into  two  laminae ;  external  to  the  lens,  the  ciliary  process- 
es and  the  intervening  pigment  mark  it  in  a  striated  man- 
ner, like  the  disk  of  a  flower;  this  appearance,  there- 
fore, has  been  called  the  ciliary  disk,  or  corona  ciliaris : 
the  vitreous  humour  serves  to  support  and  expand  the  reti- 
na, and  the  other  tunics  of  the  eye,  also,  in  transmitting 
the  rays  of  light  from  the  lens,  it  prevents  their  too  rapid 
convergence,  and  thus  causes  an  image  of  larger  size  to  be 
painted  on  the  retina. 


SECTION  V. 

OF    THE    SKIN. 

THE  integument  of  the  body  is  composed  of  one  continu- 
ed membrane,  which  is  very  dense,  at  the  same  time  very 
extensible  ;  at  the  several  orifices,  it  is  continuous  with  the 
mucous  membranes,  a  vascular  line  alone  marks  the  dis- 
tinction between  them :  by  maceration  or  putrefaction  the 
skin  may  be  divided  into  three  laminae,  the  cuticle,  rete 
mucosum,  and  cutis  vera. 

The  cuticle  or  epidermis  is  the  external  layer,  it  is  dry,  thin, 


372  DUBLIN    DISSECTOR. 

and  transparent,  and  destitute  of  nerves  and  vessels ;  it  is 
most  intimately  connected  to  the  cutis  by  numerous  fine 
hairs  which  pass  through  it,  also  by  the  several  exhalant 
and  absorbent  vessels  that  open  on  its  surface  by  very 
minute  pores  ;  in  some  situations  it  is  very  dense  and  opaque 
as  in  the  hands  and  feet ;  it  is  continued  as  a  very  fine 
pellicle  into  the  different  orifices,  and  can  be  traced  for  a 
considerable  distance  on  the  mucous  membranes,  thus,  from 
the  lips  it  extends  over  the  pharynx  and  along  the  oesopha- 
gus as  far  as  the  cardiac  orifice  of  the  stomach,  where  it 
terminates  in  a  firnbriated  margin ;  from  the  external  ear 
it  extends  along  the  meatus  externus,  and  covers  the  mem- 
brana  tympani;  inferiorly  also  it  is  continued  along  the 
mucous  lining  of  the  urethra,  vagina,  and  rectum;  the 
cuticle  serves  to  defend  certain  parts  of  the  body  from 
pressure,  to  protect  its  surface  from  contact,  and  to  prevent 
evaporation. 

The  rete  mucosum  is  a  very  thin,  soft,  vascular  lamina, 
adhering  to  the  cutis,  connected  to  it  by  vessels,  it  has  a 
villous  appearance,  and  is  tinged  with  a  mucous  fluid,  which 
presents  different  shades  of  colour  in  different  situations  and 
in  different  individuals ;  the  peculiar  complexion  or  colour 
of  the  body  depends  upon  this  secretion :  in  the  negro,  it 
is  very  thick  and  black,  while  the  cuticle  is  transparent, 
and  the  cutis  vascular  and  red  ;  some  anatomists  divide  the 
rete  mucosum  into  two,  and  some  even  into  three  or  four 
laminae. 

The  cutis  vera,  dermis,  or  chorion,  is  much  more  dense  than 
either  of  the  preceding  laminae,  it  is  very  tough  and  strong, 
in  some  situations  more  so  than  in  others ;  its  internal  sur- 
face is  cellular,  its  external  is  smooth  and  very  vascular, 
[and  is  sometimes  spoken  of  as  a  distinct  lamina,  under 
the  name  of  the  corpus  or  rete  vasculosum :]  it  is  also  highly 
sensible,  particularly  in  some  situations,  as  in  the  fingers 
and  toes,  where  numerous  nerves  are  distributed  to  it  in  the 
form  of  small  conical  or  oval  papillae  ;  these  are  very  dis- 
tinct at  the  end  of  each  finger,  they  are  very  vascular,  and 
into  each  a  nervous  filament  can  be  traced,  in  these  papil- 
lae the  sense  of  touch  more  particularly  resides.  Although 
this  sense  resides  more  exquisitely  in  these  particular  situa- 
tions, yet  many  other  parts  of  the  body  possess  more  or 
less  of  sensibility  to  the  contact  of  foreign  bodies,  as  well 
as  to  heat  and  cold  :  the  skin  generally  is  endowed  with 
this  faculty,  also  the  voluntary  muscles",  the  mucous  sur- 
faces too,  as  far  as  we  are  acquainted  with  them,  possess 
it,  and  some  as  the  conjunctiva,  the  membrane  of  the  nose, 
mouth,  fauces,  larynx,  &c.  even  in  a  more  eminent  degree 


DUBLIN    DISSECTOR  373 

than  the  surface  of  the  body ;  the  lining  membrane  of  the 
rectum,  urethra,  vagina,  &c.  are  all  sensible  to  touch  as 
well  as  to  heat  and  cold.  The  sense  of  touch,  as  possessed 
by  the  voluntary  muscles  and  by  the  integuments  of  the 
trunk  and  extremities,  depends  on  the  posterior  or  the  gan- 
glionic  roots  of  the  spinal  nerves;  that  of  the  head,  face, 
eyes,  nose,  mouth,  &c.  on  the  ganglion ic  portion  of  the  fifth 
pair  of  cerebral  nerves,  and  that  of  the  pharynx,  stomach, 
larynx,  &c.  on  the  glosso-pharyngeal  and  the  vagi;  the 
sensibility  of  the  gen i to-urinary  surfaces  most  probably 
depend  on  their  supply  of  spinal  nerves.  How  far  the 
abdominal  mucous  surface,  below  the  stomach,  enjoys  sen- 
sibility to  touch  is  uncertain,  most  probably  it  possesses  it 
only  in  a  very  faint  degree,  and  this  would  lead  to  the 
question,  are  the  branches  of  the  sympathetic,  sentient 
nerves?  The  greater  portion  of  the  alimentary  canal 
being  supplied  from  this  source,  and  not  being  endowed 
with  touch,  would  induce  us  to  give  a  negative  answer  to 
this  quere. 

The  cellular  membrane  is  connected  to  the  deep  surface  of 
the  cutis,  which  is  itself  cellular ;  the  sub-cutaneous  cel- 
lular tissue  is  considered  by  some  as  a  part  of  the  integu- 
ments, and  no  doubt  it  serves  as  an  additional  covering  to 
the  body ;  this  tissue  is,  however,  extensively  distributed 
throughout  the  system,  it  enters  into  the  composition  of 
every  solid,  it  forms  the  basis  of  the  osseous  and  muscular 
systems,  it  also  serves  to  connect  some  parts  together,  to 
separate  others,  and  to  confine  all  within  their  appointed 
limits.  In  some  parts  of  the  body,  particularly  those  ex- 
posed to  pressure,  the  cells  of  the  cellular  membrane  are 
filled  with  adeps,  in  other  situations,  where  the  parts  are 
subject  to  motion,  the  cells  are  very  loose,  and  only  contain 
a  fine  serous  exhalation  as  in  the  eyelids  and  on  the  aspect 
of  expansion  of  the  joints ;  the  former  species  of  cellular 
membrane  has  been  named  adipose,  membrane  [or  adipo-cel- 
lular  tissue,]  the  latter  reticular  membrane. 

[Or  sero-cellular,  being  so  named  from  the  character  of  their  respec- 
tive secretions  :  they  co.exist  in  an  inverse  ratio,  and  the  former  does 
not  exist,  in  those  situations  where  the  presence  of  fat  would  interfere 
with  the  functions  of  the  organs,  as  in  the  eye  lids,  the  organs  of 
generation,  the  brain,  &c.] 

In  children  the  former  abounds  towards  the  surface  and 
is  in  small  quantity  in  the  cavities  ;  in  the  old,  on  the  con- 
trary, there  is  so  little  adeps  beneath  the  skin,  that  the  out- 
line of  the  muscles  can  be  seen,  and  the  vessels  and  other 
deeper  seated  parts  can  be  distincly  felt,  whereas  it  is  then 
32 


374  DUBLIN    DISSECTOR. 

often  found,  even  in  emaciated  subjects,  in  large  quantity 
in  the  thoracic  and  abdominal  cavities,  in  the  former  about 
the  heart,  in  the  latter  in  the  omentum,  around  the  kidneys, 
&c. ;  there  is  never  any  adipose  matter  within  the  cranium 
at  any  age,  although  cellular  membrane  can  be  demonstra- 
ted even  in  the  tissue  of  the  brain. 


PART   III 

CHAPTER  I. 

ANATOMY  OF  THE  VASCULAR  SYSTEM. 


UNDER   THIS   HEAD   WE    MAY    CONSIDER    THE     ANATOMY     OF    THE     ARTK- 
RIES,   VEINS,    AND   LYMPHATICS. 


SECTION  I. 

ANATOMY      OF    THE    ARTERIES. 

THE  principal  blood-vessels  have  been  already  described 
in  the  anatomy  of  the  different  regions ;  in  the  present 
section  the  arteries  shall  be  considered  in  a  systematic 
manner,  commencing  with  the  aorta,  and  tracing  its  branch- 
es through  all  parts  of  the  body. 

AORTA  arises  from  the  upper  part  of  the  left  ventricle,  op- 
posite the  fourth  or  fifth  dorsal  vertebra,  (see  page  73,)  as- 
cends obliquely  forwards  and  to  the  right  side,  then  turns 
backwards  and  to  the  left,  and  then  descends  along  the 
dorsal  vertebra? ;  it  thus  forms  the  arch  which  terminates  on 
the  left  side  of  the  fourth  vertebra :  the  thoracic  aorta  de- 
scends along  the  left  side  of  the  remaining  dorsal  vertebra), 
inclining  a  little  to  their  forepart  inferiorly,  and  passes  be- 
tween the  crura  of  the  diaphragm  :  the  abdominal  aorta  de- 
scends on  the  lumbar  vertebrae,  as  far  as  the  fourth  or  fifth, 
where  it  divides  into  the  two  common  iliac  arteries.  The 
aorta  is  at  first  covered  by  the  pericardium  and  the  pulmo- 
nary artery  ;  as  it  ascends  it  lies  between  this  vessel  and 
the  vena  cava ;  the  arch  lies  on  the  trachea  a  little  above 
its  division,  and  on  the  bodies  of  the  second  and  third  ver- 
tebrae. In  the  posterior  mediastinum  the  aorta  descends  on 
the  left  of  the  thoracic  duct  and  vena  azygos,  and  rather 
behind  the  oesophagus.  In  the  abdomen  it  lies  between  the. 


376  DUBLIN    DISSECTOR. 

crura  of  the  diaphragm  and  the  psose  muscles,  on  the  left 
side  of  the  vena  cava  and  behind  the  vena  porta,  the  pan- 
creas and  the  peritoneum. 

[Varieties.  The  aorta  sometimes  curves  to  the  right  instead  of  to 
the  left,  and  this  anomaly  may  or  may  not  co-exist  with  a  transposi- 
tion of  the  thoracic  and  abdominal  viscera.  The  aorta  has  been  seen 
to  arise  by  a  single  trunk,  which  soon  dividing,  one  branch  passed  in 
front  of  the  trachea,  the  other  behind  it ;  both  then  uniting  to  form 
the  descending  aorta.  The  aorta  in  many  of  the  inferior  mammalia, 
immediately  after  its  origin,  bifurcates,  so  as  to  form  an  ascending 
and  a  descending  trunk,  the  former  of  which  gives  off  the  branches 
to  the  head,  neck,  and  superior  extremities,  while  the  latter  supplies 
the  thorax,  abdomino-pelvic  cavity,  and  inferior  extremities. 

This  variety  is  peculiar  to  mammalia  with  long  necks,  and  has 
been  seen  in  the  human  subject.  The  aorta  has  been  seen  to  divide 
into  two  trunks  directly  at  its  origin,  its  orifice  being  large  and  pre- 
senting five  semilunar  valves  ;  the  two  trunks  curved  upwards  to 
the  right  and  left,  and  meeting  above,  joined  to  form  the  descending 
aorta;  each  trunk  gave  off  three  branches,  the  subclavian,  the  exter- 
nal, and  the  internal  carotids.  The  sweep  of  the  arch  of  the  aorta 
differs  in  different  subjects,  being  in  some  the  arc  of  a  small  and  in 
others  of  a  large  circle.  This  artery  usually  enters  the  abdomen,  op- 
posite the  body  of  the  twelfth  dorsal  vertebra,  and  terminates  by  bi- 
furcating over  the  inter-vertebral  substance  between  the  fourth  and 
fifth  lumbar  vertebrse  :  this  however  may  take  place,  either  above  or 
below  the  point  designated.  In  addition  to  the  anomalies  of  the  aorta 
itself  there  are  no  less  than  twenty-five  well  authenticated  varieties, 
in  the  origins  of  the  branches  coming  off  from  its  arch ;  the  descrip- 
tion and  delineation  of  which  are  given  by  Tiedemann,  and  after  him, 
but  in  a  smaller  and  more  accessible  form  by  Knox.  Most  of  these 
varieties  will  be  referred  to,  in  the  description  of  the  individual  ves- 
sels;  many  of  them  are  analogous  to  the  natural  arrangement,  in  in- 
ferior animals.  These  anomalies  may  be  arranged  under  the  three 
heads,  of  community  of  origin,  of  multiplicity  of  origin,  and  of  trans- 
position of  origin. 

The  number  of  branches  coming  off  from  the  arch  of  the  aorta, 
varies  from  two  to  six,  but  is  most  commonly  three,  being  those 
named  below,  except  the  coronary  arteries  of  the  heart,  which  are 
not  usually  described  as  branches  from  the  arch.  The  two  varieties 
most  frequently  met  with  are,  first,  that  in  which  the  arteria  innomi- 
nata,  and  the  left  carotid  artery  arise  by  a  short  common  trunk ;  .and 
second,  that  in  which  the  left  vertebral  artery  arises  directly  from  the 
arch  of  the  aorta,  between  the  roots  of  the  left  carotid  and  subclavian 
arteries.  There  are  in  the  college  museum  preparations  of  many  of 
the  arterial  varieties ;  several  valuable  preparations  are  also  to  bo 
found  in  the  private  collection  of  Dr.  Alfred  C.  Post,  of  this -city.] 

From  the  arch  of  the  aorta  five  arteries  arise,  the  right  and 
left  coronary,  the  innominata,  the  left  carotid,  and  left  sub- 
clavian. 

The  right  and  left  coronary  arteries  arise  above  two  of  the 


DUBLIN    DISSECTOR  377 

sigmoid  valves ;  the  right  proceeds  along  the  base  towards 
the  right  side  of  the  heart,  divides  into  several  long  branch- 
es, which  supply  the  parietes  of  the  right  auricle  and 
ventricle,  and  communicate  with  the  left  coronary:  the 
left  descends  obliquely  along  the  left  side  of  the  heart  sup- 
plying the  parietes  of  the  left  auricle  and  ventricle,  and 
communicating  with  the  former  around  the  base  and  apex 
of  the  heart. 

[Varieties.  The  coronary  arteries  sometimes  arise  by  a  large  com. 
mon  trunk  which  soon  bifurcates ;  sometimes  there  are  three  aud 
even  four  of  these  arteries,  arising  separately.] 

The  arteria  innominala  arises  from  the  upper  part  of  the 
arch,  ascends  obliquely  to  the  right  side,  in  front  of  the 
trachea,  and  behind  the  sterno-thyroid  muscle,  and  the  left 
vena  innominata  ;  opposite  the  sternal  end  of  the  clavicle 
it  divides  into  the  right  subclavian  and  right  carotid  ar- 
teries. 

[Varieties.  This  artery  though  usually  from  an  inch  to  an  inch 
and  a  half  in  length,  is  occasionally  two  inches  long.  It  is  some- 
times double,  that  is,  there  are  two  trunks,  coming  off  from  the  arch 
of  the  aorta,  which  bifurcate  so  as  to  form  the  subclavian,  and  coin- 
mon  carotid  arteries,  of  both  sides.  This  artery,  also  called  the 
brachio-cephalic,  is  sometimes  entirely  wanting,  the  subclavian  and 
common  carotid  of  the  right  side  arising  separately  from  the  arch  of 
the  aorta.  Small  branches  sometimes  arise  from  the  arch  of  the 
aorta,  or  from  the  arteria  innominata,  to  be  distributed  upon  the 
thymus  body  and  muscles,  at  ihe  lower  part  of  the  neck  ;  the  inferior 
thyroid,  and  the  internal  mammary  artery  also  sometimes  arise  from 
one  or  the  other  of  the  above  mentioned  trunks.  The  arteria  innomi- 
nata has  been  ligatured  by  Dr.  Mott,  but  the  patient  died  of  secon- 
dary hemorrhage  after  the  lapse  of  three  weeks.] 

The  right  and  left  [common  or  primitive] carotid  arteries;  the 
right  arises  from  the  arteria  innominata,  the  left  from  the 
arch  of  the  aorta;  these  vessels  ascend  obliquely  outwards 
as  high  as  the  os  hyoides,  opposite  which  each  divides  into 
the  internal  and  external ;  in  this  course  they  are  covered 
inferiorly  by  the  sterno-mastoid,  hyoid,  and  thyroid,  and 
omo-hyoid  muscles  ;  and  superiorly,  only  by  the  skin,  pla- 
tysma,  and  fascia  ;  the  left  is  also  covered  inferiorly  by  the 
sternum  and  the  vena  innominata,  and  at  its  origin  differs 
from  the  right  in  lying  on  the  trachea,  thoracic  duct  and 
oesophagus,  but  after  this  both  ascend  in  front  of  the  Ion- 
gus  colli  and  rectus  wapitis  muscles,  the  inferior  thyroid 
artery,  and  the  recurrent  and  sympathetic  nerves,  and  are 
enclosed  in  a  sheath  of  cellular  membrane,  along  with  and 
to  the.  trucheal  side  of  the  vagus  nerve  and  the  internal  ju- 
gular vein. 

[Varieties.    The  right  common  carotid  is  shorter  than  the  left,  by 


378  DUBLIN    DISSECTOR. 

the  length  of  the  innonainata,  the  two  are  however  equal  in  calibre, 
and  their  calibre  is  proportionally  greater  in  man  than  in  the  inferior 
animals,  which  is  in  accordance  with  the  greater  development  of  the 
cerebrum  in  the  former.  These  vessels  sometimes  result  from  the 
bifurcation  of  two  brachio-cephalic  arteries,  and  at  other  times  they 
arise  by  a  common  trunk,  which  comes  off  from  the  arch  of  the  aorta 
and  soon  bifurcates ;  in  this  case  both  subclavians  arise  directly  from 
the  arch,  one  on  each  side  of  the  carotid  trunk  or  else  both  of  them 
to  the  left  of  that  trunk ;  in  other  cases  both  carotids  arise  directly 
from  the  arch  between  the  two  subclavians,  or  to  the  right  of  them, 
or  even  alternating  with  them.  Again,  the  two  carotids,  arise  from 
a  trunk  common  to  them,  and  the  left  subclavian  ;  and  lastly,  though 
most  rarely,  there  is  no  common  carotid  artery,  but  the  aorta  being 
double,  the  external  and  internal  carotids,  arise  directly  from  its  two 
trunks.  The  left  carotid  artery  not  untrequently  arises  from  the 
arteria  innorninata.  Usually,  no  branches  are  given  off  by  the  com- 
mon carotid,  previous  to  its  bifurcation  yet  this  sometimes  happens  ; 
thus  the  inferior  thyroid,  a  supernumerary  thyroid  called  middle,  the 
internal  mammary,  a  Ihymus  artery,  have  all  been  observed  coming 
off  from  this  trunk,  and  I  have  sevtral  times  seen  one  or  more  small 
branches  distributed  upon  the  sterno-cleido-rnasto-id  muscle,  from 
which  circumstance  they  might  be  called  the  sterno-anastoid  arteries. 
The  point  of  bifurcation  of  the  common  carotid,  is  not  invariable,  it 
usually  is  opposite  the  upper  edge  of  the  thyroid  cartilage,  but  I  have 
a  preparation,  taken  from  a  female,  about  twenty-rive  years  of  age, 
in  whom  the  bifurcation  on  the  left,  side  look  place  opposite  the  infe- 
rior edge  of  the  thyroid  cartilage,  and  on  the  right  side,  opposite  the 
middle  of  ihe  same  cartilage  :  in  fact  the  bifurcation  may  take  place 
at  almost  any  point,  between  the  origin  of  the  artery,  and  its  usual 
termination.] 

The  external  carotid  artery  ascends  obliquely  backwards 
to  the  forepart  of  the  meatus  auditorius,  covered  by  the 
skin,  platysma,  and  fascia,  also  by  the  lingual  nerve,  and 
digastric  and  stylo-hyoid  muscles,  the  parotid  gland  and 
portiodura  nerve  :  it  lies  superficial  to  the  internal  carotid, 
stylo-pharyngeus,  and  stylo-glossus  muscles,  the  glosso- 
pharyngeal  nerve,  and  part  of  the  parotid  gland ;  it  gives 
off  the  following  arteries,  anteriorly,  the  superior  thyroid, 
lingual,  and  labial ;  posteriorly,  the  muscular,  auricular, 
and  occipital ;  superiorly,  the  pharyngeal,  transverse  fa- 
cial, temporal,  and  internal  maxillary. 

[Variety.  This  artery  may  arise  dir-ectly  from  the  aorta,  it  is 
smaller  than  the  internal  carotid  in  the  adult,  and  much  smaller  in 
the  child,  and  is  situated  rather  at  the  internal  edge  of  that  artery 
near  ats  origin  ;  it  may  come  off  from  the  common  carotid,  at  any 
point  between  the  origin  of  that  vessel,  and  the  superior  margin  of 
the  thyroid  cartilage.] 

The  superior  thyroid  artery  arises  opposite  the  cornu  of  the 
thyroid  cartilage,  descends  obliquely  forwards  and  inwards 
beneath  the  sterno-thyroid,  and  omo-hyoid  muscles,  and 


J3TJBLIN    DISSECTOR.  379 

sends  off  the  following  branches  -.—first,  the  superficial,  dis- 
tributed to  the  integuments  and  superficial  muscles;  se- 
cond, the  laryngeal,  accompanying  the  superior  laryngeal 
nerve  between  the  os  hyoides  and  thyroid  cartilage,  and 
distributed  to  the  muscles  and  mucous  membrane  of  the 
larynx ;  third,  hyoidean,  small  and  irregular,  to  the  lower 
border  of  the  os  hyoides  and  adjacent  muscles  ;  and  fourth, 
superior  thyroid,  is  distributed  to  the  thyroid  body. 

[Varieties.  This  artery  is  not  urifrequently  double,  it  may  arise 
direotly  at  the  bifurcation  of  the  common  carotid,  or  fairly  from  the 
common  carotid  ilself;  from  either  point  it  may  arise  singly,  or  in 
common  w.tii  the  lingual  artery  and  in  like  manner  from  its  normal 
point  of  origin ;  the  iaryngeal  artery  sometimes  arises  directly  from 
the  common  carotid,  and  sometimes  from  the  lingual  arlery.] 

The  lingual  arlery  arises  immediately  above  the  preced- 
ing, it  ascends  tortuously  and  obliquely  forwards  and  in- 
wards, above  the  os  hyoides  to  the  base  of  the  tongue,  be- 
tween the  hyo  and  the  genio-hyo-glossi  muscles,  and  then 
runs  horizontally  forwards  towards  the  tip  of  the  tongue; 
it  gives  off  the  following  branches,  first,  hyoidean,  small  and 
irregular  4  second,  dorsalis  lingua,  which  ascends  to  the 
dorsum  of  the  tongue,  and  is  lost  on  the  mucous  membrane, 
near  its  base,  also  on  the  velum  and  fauces;  third,  suhlin- 
gual,  passes  forwards  and  outwards  to  the  sublingual  gland, 
mylo-hyoid  muscle,  and  mucous  mernbnme  of  the  mouth  ; 
and  fourth,  ranuie,  which  continues  along  the  lingualis 
muscle  to  the  tip  of  the  tongue. 

[Varieties.  This  arteiy  may  arise  by  a  common  trunk,  with  either 
the  superior  thyroid,  or  the  facial  arlery  :  or  it  may  be  a  branch  of 
the  former.  The  dorsal  .artery  of  the  tongue  sometimes  arises  from 
the  supeiior  thyroid;  and  the  s-isblingual  artery,  by  a  trunk  common 
to  itst-if  and  the  submenlal,  from  the  facial  or  labial  artery-  The 
branches  of  the  lingual  artery  do  not  anastomose  freely  across  the 
median  line,  in  the  subsfai.ce  of  the  tongue,  as  has  been  already 
mentioned  in  the  discription  of  that  organ.] 

The  labial  [or  facial,]  or  external  maxillary  artery  arises  op- 
posite the  us  hyoides,  ascends  obliquely  forwards  behind  the 
digastric  and  between  the  submaxiilary  gland  and  the  base 
of  the  jaw,  turns  round  the  latter  anterior  to  the  m  isseter 
muscle,  and  then  ascends  obliquely  forwards  and  inwards 
towards  the  side  of  the  nose  ;  in  the  neck  it  gives  off,  first, 
inferior  palatine.,  which  ascends  along  the  side  of  the  phar- 
ynx, and  supplies  the  velum  and  the  amygdala ;  the  branch 
to  the  latter  often  arises  distinctly  ;  second,  glandular  to  the 
sub-oiaxillary  gland  and  adjoining  lymphatic  ganglia ; 
third,  submental  runs  along  the  mylo-hyoid  muscle  to  the 
chin,  and  supplies  the  surrounding  muscles.  On  the  face 
it  gives  off,  fourth,  inferior  labial  to  the  muscle  and  integu- 


380  DUBLIN    DISSECTOR. 

ments  between  the  lip  and  the  chin  ;  fifth,  the  inferior  and 
superior  coronary,  these  run  along  the  border  of  the  lips 
close  to  the  mucous  membrane  and  directly  join  those  from 
the  opposite  side ;  sixth,  lateralis  nasi  to  the  muscles  and 
skin  on  the  side  and  dorsum  of  the  nose ;  and  seventh,  an- 
gularis,  which  communicates  with  the  ophthalmic. 

[Varieties.  This  artery  sometimes  arises  by  a  common  trunk  with 
the  lingual;  that  of  one  side  is  very  large,  while  that  of  the  other  side 
is  very  small;  it  terminates  in  the  inferior  or  superior  coronary  artery, 
or  the  lateralis  nasi,  or  it  may  be  prolonged  so  as  to  form  the  frontal 
artery.  The  inferior  labial,  and  inferior  coronary  arteries  are  in  in- 
verse  ratio  to  each  other  as  to  size,  one  of  them  being  sometimes 
very  small,  in  which  case  the  other  is  proportionably  larger  than 
usual.] 

The  muscular  artery  descends  obliquely  backwards,  di- 
vides into  several  branches  which  are  principally  distri- 
buted to  the  sterno-mastoid  muscle  and  to  the  surrounding 
cellular  tissue  and  ganglia. 

The  occipital  artery  arises  opposite  the  labial,  ascends  ob- 
liquely backwards  behind  the  digastric  muscle,  then  curves 
horizontally  backwards  between  the  mastoid  process  and 
the  atlas,  and  near  the  mesial  line  it  ascends  on  the  occi- 
put ;  it  gives  off  several  muscular  branches,  some  to  the 
mastoid  and  trapezius  muscles,  several  to  the  deep  muscles 
on  the  side  and  back  of  the  neck,  and  on  the  occiput  it  di- 
vides into  tortuous  branches,  which  ascend  in  different  di- 
rections in  the  scalp,  and  inosculate  with  the  different  ar- 
teries in  that  region. 

[Varieties.  This  artery  sometimes  arises  by  a  common  trunk  with 
the  posterior  auricular,  or  it  may  arise  from  the  internal  carotid  ;  it 
sometimes  gives  off  the  stylo-mastoid  artery,  which  is  normally  a 
branch  of  the  auricular,  and  enters  the  stylo-mastoid  foramen,  to  be 
distributed  upon  the  internal  ear.] 

The  posterior  auricular  artery  arises  above,  often  in  com- 
mon with  the  occipital ;  it  ascends  behind  the  parotid  and 
between  the  meatus  auditorius  and  the  mastoid  process ; 
it  divides  into  several  branches  which  are  lost  in  the  inte- 
guments of  the  ear  and  in  the  scalp. 

[Variety.  This  artery  sometimes  takes  the  place  of  the  posterior 
branch  of  the  superficial  temporal  artery  on  the  side  of  the  head.] 

The  inferior  or  ascending  pharyngeal  artery  arises  near  the 
division  of  the  common  carotid,  ascends  vertically  to  the 
base  of  the  skull,  and  sends  off  several  pharyngeal  and 
palatine  branches,  and  ends  in  a  small  branch  [the  poste- 
rior meningeal]  that  passes  through  the  foramen  lacerum 
posterius,  and  supplies  the  dura  mater  at  the  base  of  the 
cranium. 


DUBLIN    DISSECTOR.  381 

[Varieties.  This  artery  is  sometimes  double,  it  may  arise  from 
the  external  carotid  as  usual,  from  the  angle  of  bifurcation  of  the 
common  carotid,  from  the  internal  carotid,  from  the  occipital,  or  from 
the  superior  thyroid  artery.] 

The  transverse  artery  of  the  face  arises  from  the  carotid  in 
the  parotid  gland,  accompanies  the  duct  of  Steno,  and  is 
distributed  to  the  muscles  and  integuments  of  the  face,  and 
joins  the  branches  of  the  facial  artery. 

[Variety.  This  artery  is  often  a  branch  of  the  temporal,  and  its 
calibre  is  in  inverse  ratio  to  that  of  the  facial,  the  place  of  which  it 
sometimes  supplies  upon  the  upper  lip  and  nose.] 

The  temporal  artery  ascends  through  the  parotid  gland  be- 
tween the  meatus  auditorius  and  the  articulation  of  the 
maxilla,  behind  the  zygoma,  and  divides  on  the  temporal 
fascia  into  an  anterior  and  posterior  branch ;  it  gives  off, 
1st,  branches  to  the  gland;  2nd,  anterior  auricular;  3rd,  the 
middle  temporal;  this  pierces  the  fascia  and  is  distributed  to 
the  temporal  muscle  ;  4th,  the  anterior  or  frontal  supplies  the 
skin  and  muscles  of  the  forehead,  and  joins  the  ascending 
branches  of  the  ophthalmic  artery ;  5th,  posterior  temporal 
bends  backwards  and  upwards  in  the  scalp  and  inosculates 
with  the  occipital  and  auricular  arteries. 

The  internal  maxillary  artery  ascends  obliquely  forwards 
behind  the  neck  of  the  maxilla,  between  the  pterygoid 
muscles,  then  between  the  external  pterygoid  and  the  tem- 
poral muscle  ;  it  then  bends  down  into  the  pterygo-maxil- 
jary  fossa ;  it  gives  oft'  the  following  branches^  1st,  while 
internal  to  the  neck  of  the  maxilla,  the  middle  artery  of  the 
dura  mater;  this  ascends  to  the  base  of  the  cranium,  passes 
through  the  spinous  hole  of  the  sphenoid  bone,  then  runs 
outwards  and  forwards,  and  again  ascends  along  the  great 
wing  of  the  sphenoid  bone  to  the  inferior  angle  of  the  pa- 
rietal, which  bone  it  grooves  very  deeply  ;  it  then  ascends 
between  this  bone  and  the  dura  mater,  divides  into  several 
branches,  which  ascend  obliquely  backwards,  and  are  lost 
in  the  bone  and  the  dura  mater ;  2nd,  the  inferior  dental 
arises  opposite  the  last,  descends  obliquely  forwards  be- 
tween the  bone  and  the  internal  lateral  ligament,  enters  the 
dental  foramen,  and  proceeds  beneath  the  teeth,  to  the  roots 
of  which  it  sends  very  small  arteries,  and  through  the  men- 
tal hole  it  sends  a  small  branch  to  the  muscles  and  mucous 
membrane,  arid  to  inosculate  with  branches  of  the  labial 
artery ;  between  the  pterygoid  muscles  it  sends  off ;  3rd, 
the  deep  temporal  branches,  one  posterior,  the  other  anterior ; 
these  supply  the  muscles  and  ascend  close  to  the  bone  ;  4th, 
masseteric;  5th,  pterygoid;  6th,  buccal,  to  the  buccinator 
muscle,  the  fat  and  integuments  of  the  cheek  ;  7th,  superior 
dental,  which  winds  round  the  maxillary  tuberosity  and 


382  DUBLIN    DISSECTOR. 

sends  branches  into  the  alveoli  and  to  the  gums;  in  the 
spheno-maxillary  fossa  it  gives  off;  8th,  infra-orbital^  which 
passes  along  the  canal  of  that  name,  is  distributed  to  the 
muscles  of  the  face,  and  communicates  with  the  arteries  of 
that  region  ;  9th,  nasal  passes  inwards  through  the  spheno- 
palatine  hole,  and  is  distributed  to  the  mucous  membrane 
on  the  spongy  bones  and  on  the  septum ;  10th,  the  superior 
palatine  descends  along  the  posterior  palatine  canal,  and  is 
distributed  to  the  muscles  and  to  the  mucous  membrane  of 
the  palate,  principally  to  the  hard  palate  ;  llth,  the  vidian;  •. 
this  is  a  small  branch  which  passes  backwards,  and  takes 
the  course  of  the  first  part  of  the  vidian  nerve  ;  these  ter- 
minating branches  of  the  internal  maxillary  artery  are  en- 
tangled  with  the  divisions  of  the  superior  maxillary  nerve. 
[The  extensive  distribution  of  the  internal  maxillary  artery  may  be 
seen  by  the  following  enumeration  of  the  organs  supplied  by  it :  viz. 
the  superior  and  inferior  maxillary  bones,  and  the  corresponding  teeth, 
the  muscles  of  mastication,  the  palatine  arches,  the  soft  paiale,  and 
the  pharynx ;  the  nasal  cavities,  the  internal  ear,  the  muscles  and  in. 
teguments  of  the  face,  and  the  bones  of  the  cranium  and  the  dura 
mater.] 

The  internal  carotid-  artery  ascends  along  the  vertebral  co- 
lumn and  the  side  of  the  pharynx  from  the  common  caro- 
tid, posterior  and  external  to  the  external  carotid,  behind 
the  digastric  and  styloid  muscles,  internal  to  the  jugular 
vein  and  anterior  to  the  vagus  and  sympathetic  nerves,  to 
the  foramen  caroticum  in  the  petrous  bone ;  it  then  bends 
tortuously  forwards,  upwards,  and  inwards,  through  the 
carotid  canal  accompanied  by  the  superior  branches  of  the 
sympathetic,  enters  the  cavernous  sinus,  through  which  it 
makes  two  remarkable  turns  internal  to  the  sixth  pair  of 
nerves,  and  arriving  at  the  anterior  clinoid  process,  it  bends 
upwards  and  backwards,  and  a  little  outwards,  and  oppo- 
site the  internal  extremity  of  the  fissure  of  Sylvius  it  di- 
vides into  its  three  terminating  branches,  it  first  gives  off 
the  ophthalmic  artery ;  in  the  neck,  and  in  the  carotid  canal, 
it  sends  small  and  unimportant  branches  to  the  surround- 
ing parts. 

[Variety.  This  artery,  though  rarely,  may  arise  directly  from  the 
aorta,  as  when  the  latter  vessel  is  double.  The  calibre  of  this  artery 
is  in  direct  ratio  with  the  development  of  the  cerebrum,  and  in  the 
animal  scale,  it  is  in  proportion  to  that  of  the  external  carotid,  as  the 
development  of  the  brain  is  to  that  of  the  face.] 

The  ophthalmic  artery  arises  close  to  the  anterior  clinoid 
process,  passes  forward  through  the  optic  foramen,  below 
the  optic  nerve  and  external  to  it;  in  the  orbit  it  rises 
above  this  nerve  and  twines  round  it  to  the  inner  side  of 
this  cavity,  along  which  it  passes  to  the  inner  canthus 


DUBLIN    DISSECTOR.  383 

where  it  terminates ;  while  on  the  outer  side  of  the  optic 
nerve  it  sends  off,  1st,  centralis  retina,  which  is  very  small, 
pierces  the  sheath  of  the  optic  nerve  and  passes  along  the 
centre  of  the  latter,  into  the  eye,  where  it  divides  into  deli- 
cate ramifications ;  these  spread  along  the  internal  layer 
of  the  retina,  and  one  or  two  pierce  the  vitreous  humour, 
and  extend  to  the  capsule  of  the  lens ;  2nd,  the  lachrymal 
passes  along  the  external  rectus  muscle,  and  supplies  the 
lachrymal  gland,  and  the  external  part  of  the  palpebrse : 
while  above  the  optic  nerve  it  gives  off;  3rd,  the  supra- 
orbital,  which  passes  forwards  along  the  levator  palpebrae, 
and  through  the  superciliary  notch,  supplies  the  muscles 
and  integuments  of  the  eyebrow,  and  ascending  on  the 
forehead,  divides  into  several  branches,  which  are  distri- 
buted to  the  scalp,  and  communicate  with  the  temporal  and 
occipital  arteries  ;  4th,  the  posterior  ciliary,  ten  or  twelve  in 
number,  very  small,  surround  the  optic  nerve,  and  pierce 
the  back  part  of  the  sclerotic ;  pass  between  it  and  the 
choroid,  and  are  distributed  to  the  latter ;  some  of  their 
branches  continue  as  far  as  the  ciliary  processes  and  the 
iris ;  5th,  long  ciliary,  one  on  each  side  ;  they  pass  horizon- 
tally forwards,  between  the  sclerotic  and  choroid  mem- 
branes, as  far  as  the  ciliary  circle  ;  here  they  divide,  and 
form  a  circular  inosculation  round  the  circumference  of  the 
iris,  from  this  several  branches  radiate  inwards,  and  again 
unite  in  a  circle  near  the  pupil ;  6th,  muscular  arteries,  to 
the  different  muscles  in  the  orbit ;  7th,  ethmoidal,  passes 
through  the  posterior  orbital  foramen  to  the  mucous  mem- 
brane in  the  ethmoid  cells ;  8th,  superior  and  inferior  palpe- 
bral,  to  the  palpebrse,  caruncula,  conjunctiva,  and  lachry- 
mal sac  ;  9th,  nasal,  passes  beneath  the  trochlea,  along  the 
side  of  the  nose,  and  inosculates  with  the  labial  artery ; 
10th,  frontal,  ascends  to  the  eyebrow  and  forehead. 

The  posterior  communicating  artery  arises  from  the  carotid, 
opposite  the  ophthalmic ;  passes  backwards  and  inwards, 
external  to  the  corpora  rnamillaria,  and  joins  the  posterior 
cerebral  artery  ;  this  artery  forms  the  lateral  part  of  the 
circle  of  Willis ;  it  sends  several  branches  to  the  surround- 
ing pia  mater. 

[Variety.  This  artery  is  sometimes  the  largest  branch  of  the  in- 
ternal  carotid,  and  then  forms  the  principal  origin  of  the  posterior 
cerebral  artery.] 

The  anterior  cerebral  artery,  or  arteria  calJosa,  passes  for- 
wards and  inwards  above  the  optic  nerve;  anastomoses 
with  the  opposite,  by  a  short  transverse  branch,  (the  ante- 
rior communicating  artery,)  it  then  bends  upwards  and 
backwards  round  the  corpus  callosum,  on  which  it  termi- 


384  DUBLIN    DISSECTOR. 

nates  by  dividing  into  branches  for  the  corresponding  he- 
misphere of  the  cerebrum. 

[Variety.  The  anterior  communicating  artery,  is  usually  of  large 
calibre,  and  from  one  to  two  lines  in  length,  but  sometimes  it  is  so 
short,  that  the  two  anterior  cerebral  arteries  appear  to  be  confounded 
at  that  point ;  at  other  times  its  place  is  supplied  by  two  smaller  ar- 
teries.] 

The  middle  cerebral  artery,  very  large,  passes  outwards  in 
the  fissure  of  Sylvius,  and  divides  into  two  tortuous  branch- 
es, which  supply  the  anterior  and  middle  lobes  of  the  ce- 
rebrum. (See  page  291.) 

The  subclavian  arteries;  the  right  arises  from  the  arteria 
innominata,  and  proceeds  nearly  transversely  outwards, 
between  the  scaleni  muscles,  then  obliquely  downwards 
and  outwards  behind  the  clavicle  ;  it  is  covered  at  first  by 
the  sterno-mastoid,  hyoid,  and  thyroid  muscles ;  by  the  in- 
ternal jugular  vein,  the  vagus,  and  branches  of  the  sympa- 
thetic nerve  ;  next,  by  the  phrenic  nerve  and  anterior  sea- 
lenus  muscle,  and  externally  only  by  the  skin,  platysma, 
and  fascia  ;  it  first  passes  over  the  recurrent  nerve,  the  lon- 
gus  colli  muscle,  and  sympathetic  nerve ;  next,  the  pleura 
and  middle  scalenus  muscle,  and  lastly,  the  first  rib.  The 
left  subclavian  arises  from  the  posterior  part  of  the  arch  of 
the  aorta,  ascends  nearly  vertically  out  of  the  chest ;  then 
turns  outwards  and  downwards  between  the  scaleni  mus- 
cles, and  over  the  first  rib  ;  in  the  chest  this  artery  lies  very 
deep,  and  is  covered  by  the  pleura  and  the  lung,  also  by 
the  vena  innominata,  the  vagus,  the  sternum,  and  the  mus- 
cles attached  to  it ;  it  lies  near  the  vertebrae,  along  the  side 
of  the  oesophagus  and  thoracic  duct ;  in  the  rest  of  its 
course,  its  relations  are  similar  to  those  of  the  right ;  each 
sends  off  the  following  branches,  vertebral,  thyroid  axis, 
internal  mammary,  superior  intercostal,  and  deep  cervical. 

[Varieties.  Both  subclavian  arteries  sometimes  arise  directly  from 
the  arch  of  the  aorta,  one  on  either  side  of  the  carotids,  both  to  the 
left  of  the  carotids,  or  alternating  with  the  carotids ;  the  left  subcla- 
vian may  arise  by  a  common  trunk  with  the  left  carotid,  forming  a 
left  arteria  innominata  ;  the  right  subclavian  sometimes  arises  from 
the  left  extremity  of  the  arch,  even  as  low  as  the  fourth  dorsal  ver- 
tebra, and  then  turning  to  the  right,  passes  behind  the  oesophagus  or 
between  it  and  the  trachea,  or  even  in  front  of  the  latter  :  (he  right 
subclavian,  is  sometimes  the  second  brancli  from  the  arch,  and  passes 
behind  the  carotid  of  the  same  side  ;  the  left  snbclavian  sometimes 
arises  by  a  trunk  common  to  itself  and  both  of  the  carotids.] 

The  vertebral  arlery  arises  from  the  upper  and  back  part 
of  the  subclavian  :  ascends  behind  the  inferior  thyroid  ar- 
tery, enters  the  foramen  in  the  transverse  process  of  the 
fifth  or  sixth  cervical  vertebra,  and  ascends  through  the 


DUBLIN    DISSECTOR.  385 

several  foramina  in  the  superior  vertebrse  as  high  as  the 
second ;  it  then  bends  backwards  and  outwards ;  passes 
through  the  foramen  in  the  transverse  process  of  the  atlas  ; 
it  then  turns  backwards  aud  inwards,  round  the  articula- 
tion of  this  vertebra  with  the  condyle,  and  pierces  the  dura 
mater;  it  then  ascends  obliquely  inwards  and  forwards 
between  the  olivary  and  pyramidal  bodies,  and  at  the  low- 
er edge  of  the  pons  it  unites  with  the  opposite,  to  form  the 
basilar  artery;  in  this  course  it  gives  small  branches  to 
the  spinal  nerves  and  to  the  inter-vertebral  muscles  ;  at  the 
foramen  magnum  it  gives  off,  first  and  second,  the  posterior 
and  anterior  spinal  arteries,  which  descend  all  along  the  spi- 
nal cord ;  third,  the  inferior  cereballar  artery  often  arises 
from  the  basilar ;  it  runs  tortuously  around  the  medulla 
oblongata,  below  the  vagus,  and  sends  its  numerous  branch- 
es to  the  inferior  surface  of  the  cerebellum. 

[Varieties.  The  two  vertebral  arteries  sometimes  differ  very  much 
in  their  calibre,  that  of  the  left  side  being  more  frequently  the  largest ; 
these  arteries  usually  enter  the  transverse  foramina  of  the  sixth  cervi- 
cal vertebrae,  but  they  may  enter  those  of  the  fifth,  fourth,  third,  or 
second.  The  left  vertebral  artery  seems  most  subject  to  anomalies 
of  which  the  most  frequent  is  its  origin  from  the  arch  of  the  aorta 
between  the  left  carotid  and  the  left  subclavian  ;  it  may  also  arise 
from  the  arch  at  the  left  of  the  subclavian  ;  or  by  two  roots,  one  com- 
ing off  from  the  aorta,  as  in  the  first  variety,  trie  other  from  the  left 
subclavian,  and  the  two  uniting  at  the  fifth  cervical  vertebra  ;  or 
again,  both  roots  may  arise  from  the  subclavian.  Both  vertebral  ar- 
teries sometimes  arise  from  the  arch  of  the  aorta,  their  relations  to 
the  other  branches  varying  in  different  subjects.  The  right  vertebral 
artery  sometimes  arises  from  the  angle  of  the  bifurcation  of  the  arteria 
innominata.  The  anterior  spinal  arteries  unite  soon  after  their  origin 
to  form  a  single  trunk,  which  is  continued  down  the  spinal  canal.] 

The  basilar  artery,  is  formed  by  the  confluence  of  the  two 
vertebrals,  it  ascends  in  the  median  groove  on  the  pons 
Varolii,  sends  small  branches  to  the  surrounding  mem- 
brane, and  at  the  upper  edge  of  that  body  it  divides  into 
four  branches,  two  for  each  side,  first,  the  superior  cerebellar 
artery,  passes  outwards  and  backwards,  to  the  upper  sur- 
face of  each  hemisphere  of  the  cerebellum  on  which  it 
spreads  its  branches ;  second,  the  posterior  cerebral  artery, 
this  receives  the  posterior  branch  of  the  internal  carotid, 
bends  backwards  and  outwards,  and  spreads  its  ramifica- 
tions on  the  posterior  lobe  of  the  cerebral  hemisphere. 
(See  page  351.) 

The  thyroid  axis,  arises  from  the  upper  part  of  the  sub- 
clavian close  to  the  scalenus  and  phrenic  nerve,  it  imme- 
diately divides  into  the  four  following  branches : — First, 
the  inferior  thyroid,  ascends  tortuously  behind  the  common 
carotid,  then  bends  downwards  and  inwards,  sends  branch- 

33 


386  DUBLIN    DISSECTOR. 

es  to  the  trachea,  oesophagus,  &c.,  and  is  distributed  to  the 
thyroid  gland,  in  which  it  inosculates  with  the  superior 
thyroid,  and  with  the  arteries  of  the  opposite  side ;  second, 
the  ascending  cervical  ascends  along  and  is  distributed  to  the 
anterior  scalenus,  longus  colli,  and  rectus  capitis  anticus 
major  muscles ;  third,  supra-scapular  runs  obliquely  out- 
wards and  downwards  beneath  the  clavicle,  passes  above 
the  notch  in  the  superior  costa  of  the  scapula,  supplies  the 
supra-spinatus  muscle,  and  descends  beneath  the  acromion 
process  to  the  infra-spinatus  and  teres  minor  muscles  ; 
fourth,  transversalis  colli  ascends  obliquely  outwards  round 
the  scaleni  muscles,  and  beneath  the  trapezius,  it  divides 
into  branches,  one,  the  cervicalis  superficialis,  supplies  the 
superficial  muscles  on  the  side  and  back  part  of  the  neck ; 
the  other,  the  posterior  scapular  artery, -descends  beneath  the 
lavator  anguli  scapulae,  and  the  rhomboid  muscles  along 
the  base  of  the  scapula  as  far  as  the  inferior  angle,  where 
it  inosculates  with  the  subscapular  artery ;  the  posterior 
artery  of  the  scapula,  as  also  the  supra-scapular  in  many 
subjects,  arise  distinctly  from  the  subclavian  artery. 

[Varieties.  The  inferior  thyroid  artery  may  arise  singly,  or  by  a 
trunk  common  to  itself  and  the  supra-scapular,  or  the  transversalis 
colli,  or  the  internal  mammary  ;  it  may  arise  from  the  common  caro- 
tid ;  fronr  the  arteria  innominata,  or  from  the  arch  of  the  aorta,  either 
between  the  innominata  and  the  left  carotid,  or  the  left  carotid  and 
subclavian  of  the  same  side.  When  arising  from  either  of  the  three 
last  points,  it  is  sometimes  called  the  middle  thyroid,  and  the  usual 
inferior  thyroids  if  existing,  are  but  small  branches,  often  not  distri- 
buted at  all  upon  the  thyroid  body.  Sometimes  there  are  two  infe- 
rior thyroid  arteries  upon  the  one  side  or  the  other,  one  arising  as 
usual,  the  other  from  the  common  carotid ;  occasionally  this  artery 
arises  on  one  side  only,  and  bifurcates  to  form  the  right  and  left  thy- 
roids. The  supra-scapular  artery  sometimes  arises  in  common  with 
the  inferior  thyroid  alone,  or  that  and  the  transversalis  colli,  or  some- 
times even  in  common  with  the  internal  mammary ;  it  may  arise  di- 
rectly from  the  subclavian  itself,  or  even  from  the  axillary  artery ;  in 
the  latter  case  it  is  not  so  much  exposed  in  ligaturing  the  subclavian 
behind  the  clavicle.  The  transversalis  colli  arises  at  different  points, 
either  to  the  inside  of  the  scaleni  muscles,  between  them,  or  more 
frequently  on  their  outer  side  ;  it  may  arise  in  common  with  the  in- 
ferior thyroid,  or  the  supra- scapular.] 

The  internal  mammary  artery  arises  opposite  the  thyroid 
axis,  it  descends  obliquely  forwards  and  inwards,  between 
the  cartilages  of  the  ribs  and  the  pleura,  as  far  as  the  ensi- 
form  cartilage,  it  gives  branches  to  the  pleura,  pericardium, 
and  mediastinum,  a  long  branch  to  the  diaphragm,  which 
accompanies  the  phrenic  nerve,  also  intercostal  branches, 
which  inosculate  with  the  aortic  intercostals ;  it  terminates 
by  sending  branches  to  the  diaphragm,  and  to  the  abdo- 


DUBLIN    DISSECTOR.  387 

minal  muscles,  the  latter  inosculate  with  the  epigastric  ar- 
tery. 

[Varieties.  This  artery  on  the  right  side,  has  been  seen  to  arise 
from  the  arch  of  the  aorta,  and  from  the  arteria  innominata,  it  also 
sometimes  arises  in  common  with  the  inferior  thyroid.] 

The  superior  intercostal  artery  arises  between  the  scaleni, 
descends  behind  the  pleura,  in  front  of  the  neck  of  the  first 
and  second  ribs,  and  supplies  the  two  first  pair  of  intercos- 
tal muscles. 

The  cervicalis  profunda  arises  opposite  the  last,  ascends 
obliquely  backwards  and  outwards,  between  the  transverse 
processes  of  the  sixth  and  seventh  cervical  vertebrae,  and 
ascending  on  the  back  of  the  neck,  supplies  the  complexus 
and  the  other  deep  muscles  in  that  region,  and  inosculates 
with  the  descending  branches  of  the  occipital  artery. 

[Variety.  This  artery  sometimes  arises  in  common  with  the  supe- 
rior intercostal.  Cruveilhier  says,  that  it  invariably  passes  backwards 
between  the  transverse  process  of  the  seventh  cervical  vertebra  and 
the  first  rib,  and  not  as  described  above.] 

The  axilliary  artery  descends  from  the  lower  edge  of  the 
first  rib,  obliquely  outwards  to  the  tendon  of  the  latissimus 
dorsi  muscle,  it  is  covered  by  the  integuments,  and  at  first 
by  the  external  border  of  the  great  pectoral  muscle,  lower 
down  by  the  great  and  lesser  pectoral,  and  still  lower  down 
by  the  tendon  of  the  great  pectoral  only ;  it  passes  over 
the  first  intercostal,  and  serratus  magnus  muscles,  the  bra- 
chial  plexus,  the  subscapular,  and  the  tendons  of  the  latis- 
simus dorsi  and  teres  major  muscles ;  the  axillary  vein  de- 
scends along  its  inner  and  anterior  part,  and  the  brachial 
plexus  lies  posterior  and  external  to  it ;  it  sends  off  the 
following  arteries,  the  thoracica  acromialis,  the  superior  and 
long  thoracic,  the  subscapular,  the  posterior  and  anterior 
circumflex. 

[Varieties.  The  anomalies  of  this  artery  principally  affect  the 
origin  of  the  ulna,  the  radial,  and  the  interosseous  arteries  ;  the  first 
of  these  is  the  one  most  commonly  arising  from  the  axillary,  but 
sometimes  all  these  come  off  from  it  simultaneously.  This  artery 
sometimes  divides  into  two  branches  of  equal  size,  of  which  one  is 
muscular,  and  gives  off  some  of  the  branches  usually  coming  from 
the  axillarv,  while  the  other  is  the  brachial  artery.  It  sometimes 
bifurcates  so  as  to  form  two  brachial  arteries  which  re-unite  low  down 
upon  the  arm.] 

The  acromial  thoracic  artery  arises  from  the  front  of  the 
axillary  below  the  subclavian  muscle,  above  the  lesser  pec- 
toral, and  opposite  the  fissure  between  the  great  pectoral 
and  deltoid  muscles ;  it  divides  into  several  branches, 
which  pass  some  to  the  pectoral  muscles,  others  to  the 
acromion  process,  deltoid  muscle,  and  integuments  of  the 


388  DUBLIN    DISSECTOR. 

shoulder  and  arm,  one  long  branch  accompanies  the  cepha- 
lic vein,  [the  deltoid  artery.] 

The  superior  thoracic  artery  arises  a  little  below  the  pre- 
ceding, sometimes  in  common  with  it,  it  passes  forwards 
and  inwards,  and  divides  into  branches  which  supply  the 
cellular  membrane  and  ganglia  in  the  axilla,  the  pectoral 
muscles,  the  breast,  and  the  integuments. 

The  long  thoracic  artery  arises  below  the  lesser  pectoral, 
descends  obliquely  forwards,  along  the  side  of  the  chest, 
parallel  to  the  lower  edge  of  the  great  pectoral,  to  which 
it  sends  some  branches,  it  terminates  in  the  intercostal  mus- 
cles and  integuments,  and  inosculates  with  the  internal 
mammary  and  the  intercostal  arteries. 

[Varieties.  This  artery  sometimes  arises  in  common  with  the 
two  last,  sometimes  in  common  with  the  subscapular,  whose  place  it 
in  part  supplies  in  other  cases.] 

The  subscapular  artery  arises  opposite  to  and  descends 
along  the  lower  edge  of  the  subscapular  muscle,  and  soon 
divides  into  an  anterior  and  posterior  branch  ;  the  former 
continues  to  descend  along  the  back  part  of  the  axilla,  and 
supplies  the  subscapular,  serratus  magnus,  and  latissimus 
dorsi  muscles  ;  the  latter  passes  backwards  round  the  infe- 
rior costa  of  the  scapula,  behind  the  long  tendon  of  the 
triceps ;  and  above  the  latissimus  and  teres  major  muscles, 
it  is  distributed  on  the  dorsum  of  the  scapula  to  the  infra- 
spinatus  and  teres  minor  muscles,  and  inosculates  with  the 
supra-scapular  artery. 

[Varieties.  This  artery  may  arise  in  common  with  the  circum- 
flex, the  long  thoracic  or  the  superior  profound  artery,  and  in  the  lat- 
ter case  is  as  large  or  even  larger  than  the  brachial.] 

The  posterior  circumflex  artery  arises  below  the  last,  some- 
times in  common  with  it,  it  passes  out  of  the  axilla  between 
the  long  tendon  of  the  triceps  and  the  humerus,  turns  round 
this  bone  between  it  and  the  deltoid  muscle,  to  which  last 
it  sends  numerous  branches. 

The  anterior  circumflex  artery  is  smaller  than  the  prece- 
ding, and  arises  either  from  it  or  from  the  axillary ;  it 
passes  outwards  round  the  anterior  part  of  the  humerus, 
beneath  the  deltoid,  coraco-brachialis,  and  biceps;  to  these 
muscles  it  sends  its  branches  ;  it  also  sends  one  long  branch 
along  the  bicipital  groove  to  the  synovial  membrane  of  the 
shoulder  joint. 

The  brachial  artery  descends  obliquely  outwards  to  the 
bend  of  the  elbow,  where  it  divides  into  the  radial  and  ul- 
nar  arteries  ;  it  is  covered  by  the  skin  and  brachial  aponeu- 
rosis,  and  inferiorly  by  the  fascia  of  the  biceps,  and  the 
median  basilic  vein  ;  it  lies  on  the  inner  side  of  the  coraco- 


DUBLIN    DISSECTOR.  389 

brachialis  and  biceps,  and  passes  over  the  upper  part  of 
the  triceps,  the  coraco-brachialis,  and  the  brachialis  anti- 
cus ;  it  is  accompanied  by  a  vein  on  either  side,  also  by  the 
median  nerve,  which  above  lies  to  its  outer,  and  below  to  its 
inner  side,  it  passes  superficial  to  the  artery  about  the  mid- 
dle of  the  arm ;  in  addition  to  several  muscular  branches 
it  sends  off  the  superior  and  inferior  profunda,  and  the 
anastomotica. 

[Varieties.  The  anomalies  of  this  artery  as  of  the  axillary,  have 
reference  principally  to  the  high  origin  of  the  radial  or  ulnar  arteries. 
This  high  bifurcation  of  the  brachial  artery  may  take  place  at  any 
point  between  the  axilla  and  the  bend  of  the  elbow  :  the  interosseous 
artery  may  also  arise  from  the  brachial.  The  high  origin  of  the 
ulna,  is  most  commonly  from  the  axillary  artery,  and  that  of  the 
radial  from  the  brachial  artery,  and  in  either  case  the  branch  is  more 
superficial  in  its  course  than  when  coming  off  at  the  usual  point : 
these  high  origins  may  occur  in  both  arms,  but  they  appear  to  be 
most  common  in  the  right  arm.  The  brachial  artery  is  sometimes 
double,  that  is  the  axillary  bifurcates,  and  the  two  trunks  thus  formed 
descend  to  the  bend  of  the  elbow,  and  re-uniting  form  a  short  trunk 
which  then  gives  off  the  ulna  and  radial.  In  the  private  museum 
of  Dr.  Alfred  C.  Post  of  this  city,  there  is  a  remarkable  variety  of 
this  artery,  on  the  left  side:  "just  below  the  axilla  it  gives  off  a 
branch,  which  runs  superficially  down  the  anterior  surface  of  the  arm, 
and  a  little  below  the  elbow,  joins  the  trunk  of  the  radial  artery,  which 
bends  abruptly  forward  to  receive  it."  These  varieties  of  the  brachial 
artery  should  be  borne  in  mind,  even  in  the  common  operation  of 
venesection,  as  in  these  cases  Ihere  is  danger  of  producing  a  traumatic 
aneurism,  which  accident  has  occurred.] 

The  superior  profunda  arises  below  the  teres  major,  ac- 
companies the  musculo-spiral  nerve  obliquely  downwards 
and  outwards,  between  the  three  heads  of  the  triceps,  and 
in  the  musculo-spiral  groove  of  the  humerus;  it  divides 
into  two  large  branches,  one  descends  in  the  triceps  to  the 
olecranon,  the  other  accompanies  the  radial  nerve  to  the 
outer  condyle,  and  communicates  with  the  radial  recurrent 
artery. 

[Varieties.  This  artery  may  arise  from  the  subscapular  or  either 
of  the  circumflex  branches  of  the  axillary  artery  :  it  sometimes  gives 
off  the  next  artery.] 

The  inferior  profunda  arises  opposite  the  tendon  of  the 
coraco-brachialis,  descends  on  the  surface  of  the  triceps, 
along  with  the  ulnar  nerve,  to  the  inner  condyle,  and  com- 
municates with  the  ulnar  recurrent. 

The  anastomotica  arises  about  two  inches  above  the  joint, 
passes  inwards,  supplying  the  adjacent  muscles,  and  inos- 
culating with  tho  preceding  and  with  the  ulnar  recurrent 
arteries. 

33* 


390  DUBLIN    DISSECTOR. 

[Variety.  This  artery  sometimes  arises  immediately  below  the 
superior  profunda.] 

In  the  triangular  hollow  at  the  bend  of  the  elbow,  the 
brachial  artery  divides  into  the  radial  and  ulnar. 

The  ulnar  artery  is  the  larger  of  the  two,  it  descends 
along  the  ulnar  side  of  the  fore  arm  to  the  palm  of  the  hand, 
covered  superiorly  by  the  superficial  flexors  and  prona- 
tors,  and  by  the  median  nerve ;  inferiorly  by  the  skin  and 
fascia,  overlapped,  however,  by  the  tendons  of  the  flexor 
digitorum  sublimis  and  flexor  carpi  ulnaris,  between  which 
it  descends  to  the  wrist ;  it  passes  over  the  brachialis  an- 
ticus,  flexor  profundus,  pronator  quadratus,  the  annular  li- 
gament of  the  carpus,  and  the  flexor  tendons  in  the  palm 
of  the  hand ;  it  is  accompanied  by  two  veins,  and  by  the 
ulnar  nerve,  the  latter  descends  along  its  ulnar  side ;  it 
gives  off,  first,  the  anterior  ulnar  recurrent,  which  ascends 
in  front  of  the  inner  condyle,  on  the  brachialis  anticus, 
and  inosculates  with  the  anastomotica  ;  second,  the  posterior 
ulnar  recurrent,  large  and  tortuous,  ascends  behind  the  in- 
ner condyle,  along  with  the  ulnar  nerve,  aud  anastomoses 
with  the  anastomotica  and  inferior  profunda  arteries ;  third, 
inter-osseal  artery,  passes  backwards  and  divides  into  an  an- 
terior and  posterior  branch  ;  the  anterior  inter-osseal  artery 
descends  along  the  forepart  of  the  inter-osseal  membrane, 
beneath  the  deep  flexors,  pierces  that  membrane  near  the 
pronator  quadratus,  and  descends  on  the  back  part  of  the 
carpus,  and  is  distributed  to  the  carpal  bones,  and  to  the 
sheaths  of  the  extensor  tendons  ;  the  posterior  inter-osseal 
artery  passes  backwards  beneath  the  anconaus,  and  de- 
scends along  the  back  of  the  fore  arm,  sending  its  branches 
to  the  extensor  muscles ;  this  artery  superiorly  sends  a  very 
large  recurrent  branch  in  the  anconseus  muscle  to  the  ole- 
cranon,  to  communicate  with  the  superior  profunda;  fourth, 
muscular  branches  to  the  two  layers  of  flexor  muscles,  and 
to  the  skin  ;  fifth,  dorsalis  carpi  ulnaris  turns  round  the  lower 
end  of  the  ulna,  and  spreads  its  branches  on  the  back  part 
of  the  wrist  and  hand  ;  sixth,  superficial  palmar,  forms  the 
palmar  arch,  bends  obliquely  across  the  palm  of  the  hand 
towards  the  thumb,  and  inosculates  with  branches  of  the 
radial  artery  ;  seventh,  ramus  profundus,  passes  beneath  the 
flexor  tendons,  across  the  fifth  and  fourth  metacarpal  bones, 
and  joins  the  deep  palmar  branch  of  the  radial  artery,  and 
thus  completes  the  deep  palmar  arch  ;  from  the  superficial 
arch  long  digital  branches  pass,  these  divide  and  supply 
the  opposite  sides  of  all  the  fingers,  except  the  radial  side 
of  the  index  finger  and  the  thumb. 

[Varieties.  These  may  be  arranged  under  two  heads  :  first,  varie- 
ties in  the  origin  and  course  of  the  ulnar  artery  itself,  and  secondly, 


DUBLIN    DISSECTOR.  391 

varieties  in  the  origin  and  distribution  of  its  branches.  First,  the 
ulnar  artery  may  arise  from  the  brachial,  but  this  is  rare ;  the 
point  at  which  it  comes  off  is  usually  about  two  inches  above  the 
bend  of  the  elbow ;  it  much  more  frequently  arises  from  the  axilla- 
ry ;  in  either  of  the  above  cases  after  reaching  the  bend  of  the  el- 
bow,  it  may  take  the  usual  course,  but  most  commonly  it  is  super- 
ficial in  its  whole  extent,  being  placed  either  beneath  the  fascia  of 
the  arm  and  fore  arm,  or  between  it  and  the  integuments.  When 
the  ulnar  artery  arises  from  the  axillary,  there  is  sometimes  a  large 
anastomotic  trunk  between  it  and  the  brachial  artery.  This  artery 
may  arise  at  the  usual  point,  but  run  superficially  down  the  fore  arm. 
Secondly,  varieties  of  the  branches :  the  interosseal  artery  may  arise 
from  the  radial,  brachial,  or  even  axillary  arteries ;  it  also  sometimes 
supplies  the  place  of  the  radial  artery,  which  is  in  that  case  very 
small.  Its  recurrent  branch  sometimes  arises  directly  from  the  in- 
terosseal,  and  perforates  the  interosseal  ligament  at  a  different  point 
from  the  parent  trunk. 

Not  unfrequently  a  branch  arises  either  from  the  interosseal  or  the 
ulnar  artery,  which  follows  the  course  of  the  median  nerve,  passing 
into  the  palm  of  the  hand  either  before  or  behind  the  annular  liga- 
ment :  from  its  relation  to  the  median  nerve,  this  artery  has  been 
called  by  Tiedemann  and  Cruveilhier,  the  median  artery.  It  is  often 
as  large  as  the  radial  and  ulnar  arteries,  and  sometimes  even  it  is 
very  large,  and  supplies  the  place  of  those  arteries  which  are  then 
in  a  rudimentary  state.  It  sometimes  arises  from  the  brachial  artery. 
Its  termination  varies  very  much;  in  some  cases  it  runs  into  the 
superficial  palmer  arch,  in  others  it  unites  with  the  radial  artery  to 
supply  the  radial  half  of  the  palm  of  the  hand ;  and  in  still  other 
cases,  it  takes  the  place  of  the  radial,  and  supplies  the  radial  half  of 
the  hand,  while  the  ulnar  artery  supplies  the  ulnar  half.  A  know- 
ledge of  this  artery  is  very  important  in  a  surgical  point  of  view. 
There  is  great  variety  in  the  arrangement  of  the  superficial  palmar 
arch  and  the  terminal  branches  of  the  ulnar  artery.  This  artery  is 
usually  distributed  to  both  sides  of  the  little,  ring,  and  middle  fingers, 
and  to  the  ulnar  side  of  the  fore  finger  ;  sometimes,  however,  it  is 
distributed  to  the  ulnar  half  of  the  hand  only,  while  the  radial  half 
is  supplied  by  the  radial  or  the  median  artery ;  in  other  cases,  the 
ulnar  artery  supplies  both  sides  of  the  thumb,  and  all  the  fingers ; 
sometimes  the  superficial  palmar  arch  is  not  joined  by  the  superficial 
volar  artery ;  at  other  times  there  is  no  arch.  There  may  be  no 
anastomotic  branch  between  the  ulnar  and  the  radial  or  median,  or 
thfre  may  be  one  just  at  the  lower  edge  of  the  annular  ligament. 
The  digital  arteries  sometimes  arise  from  the  deep  palmar  arch,  of 
which  there  is  a  preparation  in  the  valuable  private  collection  of  Dr. 
J.  Kearny  Rodgers,  if  this  city,  the  whole  of  which  collection  has 
been  deposited  by  him  in  the  College  Museum.] 

The  radial  artery  continues  in  the  direction  of  the  brach- 
ial artery ;  it  passes  along  the  radial  side  of  the  fore  arm 
to  the  wrist,  turns  round  the  external  lateral  ligament  of 
this  joint,  then  passes  forwards  between  the  heads  of  the 
two  first  metacarpal  bones  into  the  palm  of  the  hand,  and 


392  DUBLIN    DISSECTOR. 

terminates  in  three  branches  ;  in  the  fore  arm  it  is  covered 
by  the  skin  and  fascia  only,  lies  between  the  supinator 
longus  externally,  and  the  pronator  teres,  and  flexor  carpi 
radialis  internally;  it  passes  over  the  biceps,  supinator 
brevis,  pronator  teres,  flexor  digitorum  sublimis,  flexor  pol- 
licis,  and  pronator  quadratus ;  it  is  accompanied  by  two 
veins,  and  the  radial  nerve  is  to  its  external  side  in  the  mid- 
dle of  the  fore  arm ;  on  the  outer  side  of  the  wrist  it  is  co- 
vered by  the  extensor  tendons  of  the  thumb,  and  on  the 
back  of  the  hand  by  the  skin  and  fascia ;  it  gives  off,  first, 
radial  recurrent,  large  and  tortuous,  bends  outwards  and 
upwards  along  the  supinators  and  extensors,  to  which  it 
sends  several  branches,  and  inosculates  with  the  superior 
profunda ;  second,  muscular  branches  to  the  flexors  and  su- 
pinators ;  third,  superficialis  vol<c  passes  over  the  annular 
ligament  of  the  carpus,  supplies  the  small  muscles  of  the 
thumb,  and  inosculates  with  the  ulnar  artery  ;  fourth,  dor- 
salts  carpi  radialis;  fifth,  dorsales  pollicis,  these  branches  are 
distributed  as  their  names  imply  ;  sixth,  radialis  indicis,  runs 
along  the  radial  side  of  the  fore  finger  ;  seventh,  magna  pol- 
licis  runs  along  the  first  metacarpal  bone,  and  divides  into 
two  branches,  which  pass  along  the  opposite  sides  of  the 
thumb  to  its  last  phalanx  ;  eighth,  palmaris  profunda  passes 
across  the  metacarpal  bones,  joins  the  deep  branch  of  the 
ulnar,  and  thus  forms  the  deep  palmar  arch,  from  which 
several  branches  proceed  to  the  inter-osseal  muscles,  and 
to  the  bones  and  ligaments  of  the  metacarpus. 

[Varieties.  This  artery  may  arise  from  the  axillary,  but  it  comes 
off  much  more  frequently  from  the  brachial  ;  it  is  sometimes  very 
small,  and  its  place  is  then  supplied  by  the  median  artery.  The  ra- 
dial artery  of  one  side  may  be  much  smaller  than  that  of  the  other 
side.  When  this  artery  arises  high  up,  its  entire  course  is  usually 
superficial.  Sometimes  this  artery,  about  the  middle  of  the  fore  arm, 
crosses  over  its  outer  edg-es  superficial  to  the  supinator  longus  and 
the  extensor  muscles  of  the  wrist  and  thumb,  and  descends  rather  on 
the  back  of  the  fore  arm,  while  the  superficialis  voice  is  continued  in 
the  usual  course  of  the  parent  trunk.  The  superficialis  voice  is  some- 
times very  large,  and  forms  apart  of  the  superficial  palmar  arch  ;  in 
other  cases  it  is  small,  and  may  not  even  join  the  arch.  The  other 
varieties  of  the  radial  artery  have  been  sufficiently  referred  to  above.] 

The  THORACIC  AORTA  gives  off  the  bronchial,  cesophageal, 
and  intercostal  arteries. 

The  bronchial  arteries  are  two  or  three  in  number,  they 
arise  from  the  fore  part  of  the  aorta,  below  the  arch  ;  they 
pass  to  either  side,  enter  the  back  part  of  the  root  of  each 
lung,  and  are  lost  in  the  cellular  tissue  of  these  organs ; 
these  arteries  sometimes  arise  from  the  intercostal,  they 
are  very  irregular  in  number  and  size. 


DUBLIN    DISSECTOR.  393 

[Varieties.  There  are  sometimes  as  many  as  four  of  these  ar- 
teries, and  they  arise  separately,  or  by  a  common  trunk ;  those  of 
the  right  side  are  the  largest,  which  accords  with  the  greater  volume 
of  the  right  lung.  A  hrouchial  artery  is  sometimes  found  to  arise  from 
the  subclavian,  the  internal  mammary,  the  first,  second,  or  third  in- 
tercostal,  or  even  the  inferior  thyroid  artery.] 

The  cesophageal  arteries  are  also  irregular,  generally  three 
or  four  in  number ;  they  arise  from  different  parts  of  the 
aorta,  send  branches  to  the  mediastinum  and  oesophagus ; 
on  the  latter  some  ascend,  others  descend  ;  the  former  inos- 
culate with  the  cervical  arteries,  the  latter  with  the  abdomi- 
nal. 

[Variety.  There  are  sometimes  as  many  as  seven  of  these  arte- 
ries.] 

The  intercostal  arteries,  in  general  ten  on  the  left,  nine  on 
the  right  side,  the  superior  intercostal  on  the  right  side 
being  larger  than  that  on  the  left ;  they  arise  from  the 
back  part  of  the  aorta,  pass  obliquely  outwards  behind  the 
pleura,  and  enter  the  intercostal  spaces,  run  along  the 
lower  edge  of  each  rib  between  the  layers  of  muscles,  and 
about  the  middle  of  the  chest  divide  into  an  inferior  and 
superior  branch  ;  the  former,  smaller,  runs  along  the  supe- 
rior border  of  the  lower  rib ;  the  latter  continues  in  the 
groove  in  the  upper  ;  they  both  supply  the  intercostal  mus- 
cles, and  send  branches  through  these  to  the  pleura  and  to 
the  superficial  muscles  of  the  chest ;  they  inosculate  with 
the  internal  mammary  and  with  the  thoracic  arteries.  Each 
intercostal  artery,  before  it  enters  the  intercostal  space, 
sends  a  large  branch  backwards  between  the  transverse 
processes  of  the  vertebrae  to  the  muscles  on  the  posterior 
part  of  the  trunk,  these  dorsal  branches  of  the  intercostal  ar- 
teries also  send  small  branches  through  the  inter- vertebral 
holes  along  the  spinal  nerves  to  the  medulla  spinalis. 

The  ABDOMINAL  AORTA  sends  off  the  following  branches ; 
the  phrenic,  coeliac  axis,  superior  mesenteric,  inferior  rne- 
senteric,  renal,  supra-renal,  spermatic,  lumbar,  and  middle 
sacral. 

The  phrenic  arteries  arise  in  common,  or  near  each  other, 
from  the  fore  part  of  the  aorta  ;  they  both  send  branches 
to  the  supra-renal  capsules,  and  to  the  crura  of  the  dia- 
phragm ;  the  right  ascends  behind  the  vena  cava ;  the  left 
behind  the  oesophagus ;  on  the  diaphragm  each  divides  in- 
to an  external  and  internal  branch ;  the  former  passes  to- 
wards the  circumference  of  the  muscle,  and  inosculates 
with  the  internal  mammary  and  the  inferior  intercostals  ; 
the  latter  encircles  the  central  tendon,  communicates  with 
its  fellow  and  with  the  phrenic  branches  of  the  mammary. 


394  DUBLIN    DISSECTOR. 

[Varieties.  These  arteries  are  sometimes  three  and  four  in  num. 
ber,  and  they  may  arise  from  the  coeliac  artery,  or  one  of  its  branches ; 
frequently  one  artery  arises  thus,  while  the  other  comes  off  as  usual 
from  the  aorta.  One  or  more  of  them  may  arise  from  the  gastric, 
renal,  or  even  the  first  lumbar  artery.  The  gastric  and  phrenic  ar- 
teries may  form  a  common  trunk.] 

The  codiac  axis  arises  from  the  fore  part  of  the  aorta  op- 
posite the  last  dorsal  vertebra ;  it  soon  divides  into  three 
branches,  first,  the  gastric  artery  ascends  obliquely  to  the 
left  side,  to  the  cardiac  orifice  [of  the  stomach,]  to  which 
and  to  the  oesophagus  it  sends  several  branches;  it  then 
bends  along  the  lesser  curvature  towards  the  right  side  be- 
tween the  laminae  of  the  lesser  omentum,  and  inosculates 
with  the  superior  pyloric  artery ;  it  sends  its  branches  to 
the  anterior  and  posterior  surfaces  of  the  stomach  ;  second, 
hepatic  artery  ascends  obliquely  towards  the  right  side,  in 
front  and  to  the  left  side  of  the  vena  porta  and  ductus  cho- 
ledochus,  and  in  the  transverse  fissure  of  the  liver  divides 
into  right  and  left  hepatic  arteries ;  in  this  course  it  gives 
off  the  superior  pyloric^  which  passes  along  the  upper  surface 
of  the  pylorus  and  joins  the, gastric  artery  ;  and  the  gastro- 
duodenalis  which  descends  between  the  pylorus  and  the 
duodenum  ;  this  gives  off  -inferior  pyloric  branches,  and  di- 
vides into  the  pancreatico^duodenalis  and  gastro-epiploica  dex- 
tra:  the  former  takes  a  curved  course  between  the  duode- 
num and  the  pancreas,  sending  branches  to  each,  and  in- 
osculates with  the  superior  mesenteric  artery  ;  the  latter 
turns  forwards,  and  to  the  left  side  along  the  great  curva- 
ture of  the  stomach,  between  it  and  the  laminae  of  the  great 
omentum,  to  which,  as  well  as  to  the  stomach,  it  sends  nu- 
merous branches,  and  inosculates  with  the  gastro-epiploi- 
ca sinistra,  a  branch  of  the  splenic  artery  ;  the  right  and 
left  hepatic  arteries  then  separate  and  plunge  into  the  sub- 
stance of  the  liver,  accompanying  the  branches  of  the  vena 
porta :  the  right  hepatic  is  the  larger,  and  before  it  enters 
the  gland  it  gives  off  the  cystic  artery  which  supplies  the 
parietes  of  the  gall-bladder  ;  third,  the  splenic  artery  is  the 
longest  branch  of  the  coeliac  axis ;  it  passes  backwards 
and  to  the  left  side  along  the  upper  edge  of  the  pancreas, 
to  which  it  sends  several  branches:  near  the  spleen  it  gives 
off  the  gastro-epiploica  sinistra ;  this  bends  forwards,  and  to 
the  right  side  along  the  great  curvature  of  the  stomach,  and 
between  the  laminse  of  the  great  omentum,  it  inosculates 
with  the  corresponding  branch  from  the  hepatic  artery ; 
the  splenic  next  sends  off  the  vasa  brevia,  five  or  six  small 
branches  which  pass  to  the  great  end  of  the  stomach,  and 
inosculate  with  the  proper  gastric  arteries ;  the  splenic 
artery  then  divides  into  several  branches,  which  enter  the 


DUBLIN    DISSECTOR.  395 

foramina  on  the  concave  surface  of  the  spleen,  and  ramify 
through  its  spongy  substance. 

[Varieties.  The  gastric  artery  sometimes  gives  off  one  of  the  he- 
patic  arteries,  and  sometimes  the  left  phrenic  artery.  The  hepatic 
artery  sometimes,  though  rarely,  comes  off  separately  from  the  aorta. 
It  may  also  arise  from  the  superior  rnesenteric  artery.  There  are 
sometimes  two  hepatic  arteries ;  one,  the  left,  arising  from  the  gas- 
trie,  and  the  other  from  the  superior  mesenteric  ;  and  sometimes 
there  is  a  third  coming  off  from  the  coeliac.  Sometimes  when  the 
hepatic  artery  is  derived  from  the  superior  mesenteric,  the  right  gas- 
tro-epiploic  branch  is  given  off  by  the  coeliac.  The  left  gastro-epi. 
ploic  artery  and  the  vasa  brevia  often  come  off  from  the  terminal 
branches  instead  of  the  trunk  of  the  splenic  artery.] 

The  superior  mesenteric  artery  arises  a  little  below  the  coe- 
liac, descends  obliquely  forwards  and  to  the  left  behind 
the  pancreas,  and  over  the  duodenum ;  it  then  passes  be- 
tween the  layers  of  the  mesentery,  and  takes  an  arched 
course  towards  the  right  iliac  fossa ;  from  its  concave  side 
arise  three  branches,  the  ileo-colic,  right  colic,  and  middle  co- 
lic ;  these  three  branches  proceed  between  the  laminse  of 
the  meso-colon  to  the  large  intestine,  each  divides  into  two 
branches  which  unite  with  those  on  either  side,  and  form 
arches,  from  the  convexities  of  which  branches  arise,  some 
of  which  subdivide  and  unite  again  in  the  same  manner  as 
the  first  branches;  near  the  intestine  straight  branches 
proceed  on  the  anterior  and  posterior  surface,  and  supply 
the  muscular  and  mucous  coats ;  from  the  convex  side  of 
the  mesenteric  artery  eighteen  or  twenty  branches  arise, 
these  proceed  between  the  laminse  of  the  mesentery,  di- 
vide, and  form  arches,  from  which  new  branches  arise, 
these  again  divide,  and  again  unite  in  an  arched  manner  ; 
these  divisions  and  subsequent  inosculations  occur  three 
or  four  times  before  the  arteries  arrive  at  the  intestine ; 
near  the  latter  each  branch  divides  into  two,  which  proceed 
in  a  direct  course,  one  on  the  anterior,  the  other  on  the 
posterior  surface  of  the  intestine,  and  are  distributed  prin- 
cipally to  the  mucous  membrane. 

[Varieties.  This  artery  sometimes,  though  rarely,  arises  by  a 
common  trunk  with  the  creliac.  I  have  seen  this  variety  but  once. 
The  three  branches  given  off  from  the  concavity  of  the  artery  do 
not  often  arise  separately,  but  by  two  roots,  one  of  which  bifurcates 
to  form  the  ileo-colic  and  right  colic  arteries.  The  anastomosis  be- 
tween  the  superior  and  inferior  mesenteric  arteries  is  sometimes  en- 
tirely  wanting.] 

The  inferior  mesenteric  artery  arises  about  two  inches  be- 
low the  preceding ;  it  descends  towards  the  left  iliac  fossa 
and  divides  into  three  branches,  left  colic,  sigmoid,  and 
superior  hsemorrhoidal ;  the  left  colic  ascends  in  the  left  me- 


396  DUBLIN    DISSECTOR. 

so-colon,  anastomoses  with  the  middle  colic  branch  of  the 
superior  mesenteric,  and  supplies  the  left  part  of  the  colon ; 
the  sigmoid  artery  is  distributed  to  the  sigmoid  flexure  of 
the  colon  ;  the  superior  hamorrhoidal  descends  along  the 
back  part  of  the  rectum,  supplies  the  coats  of  this  intes- 
tine, and  inosculates  with  the  middle  and  inferior  haemor- 
rhoidal  arteries. 

The  renal  arteries  arise  from  the  sides  of  the  aorta,  be- 
tween the  superior  and  inferior  mesenteric  arteries ;  the 
right  is  longer  than  the  left :  it  passes  across  the  spine 
behind  the  vena  cava  :  both  pass  behind  their  correspond- 
ing vein,  and  divide  near  the  kidney  into  five  or  six 
branches,  which  ramify  through  the  substance  of  this 
gland. 

[Varieties.  These  arteries  are  more  frequently  the  subject  of  ano- 
malies, than  almost  any  others  in  the  body.  Sometimes  there  is  mor 
than  one  on  each  side,  or  one  on  one  side,  and  two  or  more  on  the  other. 
They  may  arise  from  the  aorta  lower  down  than  usual,  or  they 
arise  from  the  primitive  or  internal  iliac  arteries,  in  which  cases,  thei 
is  generally  a  corresponding  transposition  of  the  kidneys  into  the  ilk 
fossae,  or  the  cavity  of  the  pelvis.  Cruveilhier  has  seen  two  renal  ar- 
teries going  to  the  kidney  in  the  pelvis,  one  arising  from  the  aorta 
opposite  the  inferior  mesenteric,  the  other  from  the  angle  of  bifurca- 
tion. The  two  renal  arteries  may  arise  by  a  common  trunk  from  the 
front  of  the  aorta ;  or  again  there  may  be  but  one  renal  artery, 
there  being  but  one  kidney,  and  that  of  unusual  size,  as  in  a  prepa- 
tion  belonging  to  Dr.  Alfred  C.  Post.  Tiedemann  represents  a  kid- 
ney having  three  arteries,  one  of  which  arises  from  the  aorta  as 
usual,  the  second  from  the  angle  of  bifurcation  of  the  aorta,  and  the 
third  from  the  common  iliac  artery.  I  have  seen  three  arteries  go- 
ing to  the  left  kidney,  all  coming  off  from  the  aorta,  within  the 
space  of  half  an  inch,  while  on  the  right  side  of  the  same  subject, 
there  are  two  renal  arteries  coming  off  from  the  aorta  at  a  distance 
of  three  inches  from  each  other.  I  have  a  preparation  in  my  posses- 
sion, taken  from  a  white  female  of  about  sixty  years  of  age,  in  which 
on  the  left  side  there  are  two  renal  arteries  arising  near  together ;  on 
the  right  side  there  are  also  two  renal  arteries  arising  near  together ; 
while  a  third  arises  some  distance  below,  and  passes  in  front  of  the 
vena  cava  to  the  kidney.  I  do  not  now  recollect  that  this  anomaly 
has  been  noticed  before.] 

The  capsular  arteries  are  two  or  three  in  number ;  they 
arise  either  from  the  renal  arteries  or  from  the  aorta  ;  they 
supply  the  renal  capsules. 

The  spermatic  arteries  arise  from  the  fore  part  of  the  aorta ; 
the  left  frequently  arises  from  the  renal  artery ;  they  are 
long  and  tortuous,  descend  obliquely  outwards,  crossing  in 
front  of  the  psoas  muscle  and  the  ureter  :  in  the  male  they 
accompany  the  vas  deferens,  through  the  inguinal  canal, 
and  supply  the  testicle  and  epididymis ;  in  the  female  they 


DUBLIN    DISSECTOR.  397 

pass  to  the  ovarium,  and  also  send  branches  to  the  Fallo- 
pian tubes,  and  to  the  sides  of  the  uterus. 

[Varieties.  These  arteries  sometimes  arise  by  a  common  root; 
occasionally  there  are  two  of  them  on  one  or  both  sides ;  they  rarely 
arise  from  the  aorta  at  the  same  level ;  they  may  arise,  though  rarely, 
above  the  renal  arteries :  one  of  the  spermatics  may  arise  from  the 
capsular,  the  renal,  the  inferior  mescnteric,  or  the  internal  iliac  ar- 
tery.] 

The  lumbar  arteries  are  four  or  five  pair  ;  they  arise  from 
the  back  part  of  the  aorta,  pass  obliquely  outwards  through 
the  psoas  muscle,  send  branches  between  the  transverse 
processes  of  the  lumbar  vertebrae,  to  the  muscles  of  the 
back  and  loins,  and  terminate  in  the  abdominal  muscles. 

[Varieties.  The  first  lumbar  arteries  are  sometimes  branches  of 
the  last  intercostal :  the  fifth  lumbar  arteries  may  arise  from  the 
fourth  lumbar,  the  middle  sacral,  the  aorta,  or  the  common  iliac.] 

The  middle  sacral  artery  arises  from  the  back  part  of  the 
aorta  a  little  above  the  bifurcation  ;  it  descends  nearly  in 
the  median  line  close  to  the  sacrum,  sends  its  branches  to 
this  bone,  and  communicates  with  the  lateral  sacral  arteries. 

[Varieties.  This  artery  may  arise  from  the  left  common  iliac,  or 
rom  the  last  lumbar  artery  :  it  sometimes  arises  by  a  common  trunk 
with  the  two  last  lumbar  arteries.] 

The  common  iliac  arteries  descend  obliquely  outwards  as 
!ar  as  the  ilio-sacral  articulations,  opposite  which  each  di- 
vides into  the  internal  and  external  iliac  ;  the  right  iliac  is 
.onger  than  the  left,  and  passes  over  the  commencement  of 
the  vena  cava. 

[  Varieties.  The  length  of  this  artery  is  generally  about  two  inches, 
}ut  frequently  it  is  shorter,  and  this  is  the  case  more  often  on  the 
,eft  side.  This  artery  does  not  usually  give  off  any  branches  before 
its  bifurcation  ;  but  I  have  several  times  seen  one  or  two  branches 
from  it, distributed  principally  upon  the  psoas  magnus  muscle.  In  one 
case  the  right  common  iliac  artery  was  entirely  wanting,  the  external 
and  internal  iliacs  coming  off  directly  from  the  aorta,  which  ended  by  a 
division  into  three  branches,  the  third  being  the  left  common  iliac.] 

The  internal  iliac  or  hypogastric  artery  passes  downwards 
and  forwards  into  the  pelvis  to  the  side  and  back  part  of 
the  bladder,  where  it  ends  in  a  ligamentous  substance, 
which  ascends  first  along  the  side  of  the  bladder,  and  then 
behind  the  recti  muscles  as  far  as  the  umbilicus  ;  the  inter- 
nal iliac  artery  gives  off  the  following  branches,  ilio-lum- 
bar,  lateral  sacral,[middle]  haBmorrhoidal,  vesical,  uterine 
and  vaginal,  the  glutasal,  sciatic,  obturator,  and  [internal] 
(pudic.  First,  the  ilio-lumbar  arises  from  the  back  part  of 
[the  internal  iliac,  passes  outwards  behind  the  external  iliac 
[vessels  and  the  psoas  muscle,  into  the  substance  of  the 

34 


398  DUBLIN    DISSECTOR. 

ilacus  interims,  in  which  it  divides  into  ascending  and  de- 
scending branches.  Second,  the  lateral  sacral  descends  ob- 
liquely inwards  in  front  of  the  sacral  holes,  through  which 
it  sends  branches  to  the  spinal  nerves,  also  to  the  pyriform 
muscle,  and  to  communicate  with  the  middle  sacral.  Third, 
the  hfcmorrhoidal  are  two  or  three  branches  of  uncertain 
origin,  they  pass  to  the  sides  of  the  rectum,  and  communi- 
cate with  the  superior  and  inferior  hasmorrhoidal  arteries. 
Fourth,  the  vesical  arteries  arise  from  the  iliac,  or  from  some 
of  its  branches ;  they  ramify  on  the  coats  of  the  bladder  ; 
the  inferior  also  supply  the  parts  about  the  neck  of  this 
organ.  Fifth,  the  uterine  and  vaginal  arteries  either  arise 
from  the  internal  iliac  or  from  some  of  its  branches,  and 
are  distributed  as  their  names  imply.  Sixth,  the  glutaal 
artery  passes  backwards  and  outwards  from  the  pelvis  by 
the  upper  part  of  the  sciatic  notch,  above  the  pyriform 
muscle,  and  divides  into  several  branches,  some  of  which 
supply  the  glutseus  maximus,  others  pass  forwards  in  a 
semicircular  course  towards  the  spine  of  the  ilium,  and 
supply  the  glutaBus  medius  and  minimus  muscles.  Seventh, 
the  obturator  artery  passes  out  of  the  pelvis  by  the  superior 
part  of  the  thyroid  hole  into  the  upper  part  of  the  thigh  be- 
neath the  pectinseus,  and  divides  into  several  branches  to 
supply  the  obturator  and  adductor  muscles.  Eighth,  the 
sciatic  artery  passes  over  the  pyriform  muscle,  and  escapes 
from  the  pelvis  by  the  lower  part  of  the  sciatic  notch,  along 
with  the  sciatic  nerve ;  it  sends  several  branches  to  the 
glutseus  maximus,  the  hamstring,  and  adductor  magnus 
muscles;  also  to  the  small  capsular  muscles  and  to  the 
sciatic  nerve  ;  these  communicate  with  the  circumflex  and 
perforating  arteries.  Ninth,  the  internal pudic  artery,  smaller 
than  the  preceding,  leaves  the  pelvis  along  with  it  below 
the  pyriform  muscle,  re-enters  the  cavity  between  the 
sciatic  ligaments,  and  then  ascends  obliquely  inwards 
and  forwards  along  the  tuber  and  ramus  of  the  ischium 
and  ramus  of  the  pubis,  and  a  little  below  the  symphysis 
pubis  divides  into  two  branches.  In  the  pelvis  the  pudic 
at  first  gives  small  branches  to  the  adjoining  viscera  ;  as  it 
is  passing  round  the  spine  of  the  ischium,  and  between  the 
sciatic  ligaments,  it  gives  small  branches  to  the  surrounding 
ligaments  and  muscles  ;  when  it  has  re-entered  the  pelvis 
it  gives  off,  First,  external  or  inferior  hccmorrhoidal  arteries,  two 
or  three,  they  pass  transversely  to  the  side  of  the  rectum 
and  anus,  and  supply  the  integuments  and  muscles  in  that 
region ;  second,  the  perinatal  artery  first  descends,  then  turns 
forwards  and  upwards  round  the  transversus  perinee,  pro- 
ceeds along  the  perinseum,  and  is  distributed  to  the  mus- 
cles and  integuments  in  this  situation,  and  to  the  scrotum  ; 


DUBLIN    DISSECTOR.  399 

third,  transversalis  perincci,  a  small  branch  arising  near  to 
and  often  from  the  preceding ;  it  takes  the  course  of  the 
muscle  of  that  name,  and  is  lost  in  the  muscles  and  integu- 
ments ;  fourth,  artery  of  the  bulb,  passes  transversely  between 
the  layers  of  the  triangular  ligament,  enters  the  spongy 
substance  of  the  bulb,  and  spreads  its  branches  through 
the  corpus  spongiosum  urethrae ;  fifth  and  sixth,  artery  of 
the  corpus  cavernosum  and  dor  sails  penis ;  the  former  enters 
and  extends  along  the  corpus  cavernosum,  the  latter  along 
the  dorsum  of  the  penis  as  far  as  the  glans.  In  the  female 
the  pudic  artery  gives  off  branches  to  the  perinseum  and 
labia,  and  to  the  corpus  cavernosum  and  dorsum  of  the 
clitoris,  analogous  to,  but  smaller  than  those  in  the  male. 

[Varieties.  The  internal  iliac  artery  in  one  case  came  off  on  the 
right  side  from  the  aorta.  The  order  in  which  its  branches  come 
offis  very  variable;  sometimes  they  come  off  from  the  trunk  ;  some- 
times the  trunk  divides  into  two  large  branches,  which  give  off  the 
terminal  branches.  The  ilio-lumbar  branch  is  sometimes  double  on 
both  sides  ;  it  may  arise  from  either  of  the  following  sources,  the  com- 
mon iliac,  the  external  iliac,  or  the  gluteal,  and  more  rarely  from  the 
fourth  lumbar  or  middle  sacral  artery.  The  lateral  sacral  arteries 
are  frequently  double  on  both  sides ;  one  of  them  arising  from  the 
internal  iliac,  the  other  from  the  gluteal,  ischiatic,  or  ilio-lumbar  ar- 
tery :  this  artery  sometimes  arises  from  the  common  iliac.  The 
middle  hcemorrhoidal  arteries  may  arise  from  the  internal  iliac,  the 
lateral  sacral,  the  internal  pudic,  or  the  ischiatic  artery  ;  they  are 
sometimes  wanting.  The  vesical  arteries  vary  very  much  in  num. 
ber  and  origin ;  the  sources  from  which  they  are  derived  are  the  in- 
ternal iliac,  internal  pudic,  ischiatic,  middle  hcmorriioidal,  obturator, 
and  in  the  female  also  the  vaginal  and  uterine  arteries.  The  uterine 
artery  sometimes  forms  a  common  trunk  with  the  middle  hoemor- 
rhoidal.  The  origin  of  the  obturator  artery  is  very  irreguiar,  as  it 
may  come  off  from  almost  any  of  the  larger  branches  of  the  internal 
iliac  artery  :  it  also  frequently  arises  from  the  epigastric  artery,  or 
by  a  common  trunk  with  it  from  the  external  iliac  :  this  variety  is 
said  to  occur  once  in  three  times.  This  artery  may  arise  singly  from 
the  external  iliac  above  the  epigastric,  or  from  the  femoral  artery  be- 
low Poupart's  ligament :  these  anomalies  may  exist  on  one  side  only, 
or  on  both  sides,  and  they  are  of  importance  in  the  surgical  anatomy 
of  femoral  hernia.  The  ischiatic  artery  frequently  arises  by  a  com- 
mon trunk  with  the  gluteal,  or  the  internal  pudic  artery  The  inter, 
nal  pudic  artery  is  often  a  branch  of  the  ischiatic,  and  in  some  rare 
cases  it  does  not  pass  out  of  the  pelvis  at  the  sacro-ischiatic  notch. 
The  arteria  dorsalis  penis  sometimes  arises  from  the  internal  iliac  it- 
self, and  describes  a  long  course  within  the  pelvis,  passing  out  under 
the  symphisis  pubis.  It  sometimes  arises  from  the  obturator,  or  from 
one  of  the  external  pudic  arteries  ;  and  I  have  seen  it  in  an  adult 
negro  coming  off  directly  from  the  femoral  artery,  an  inch  below 
Poupart 's  ligament ;  it  sometimes  arises  from  the  deep  femoral  arte- 
ry. The  cavernous  artery  is  sometimes  a  branch  of  the  obturator.] 


400  DUBLIN    DISSECTOR. 

The  external  iliac  artery  proceeds  from  the  common  iliac 
downwards  and  outwards  to  Poupart's  ligament,  beneath 
which  it  passes  and  receives  the  name  of  femoral ;  it  lies 
along  the  inner  side  of  the  psoas  muscle,  the  vein  is  internal 
and  posterior  to  it,  it  gives  off  near  the  groin  two  branches  ; 
first,  circumflexa  ilii  arises  from  its  outer  side,  ascends  ob- 
liquely outwards  as  far  as  the  crest  of  the  ilium,  where  it 
divides  into  several  branches,  some  pass  to  the  abdominal 
muscles,  others  to  the  iliacus  internus  and  quadratus  lum- 
borum,  and  communicate  with  the  ilio-lumbar  artery ; 
second,  the  epigastric  artery  arises  from  its  fore  part,  a  little 
above  Poupart's  ligament,  it  at  first  descends,  then  turns 
forwards  and  ascends  between  the  abdominal  muscles  and 
the  peritonaeum,  crosses  behind  the  spermatic  cord,  a  little 
internal  to  the  internal  inguinal  ring;  about  three  or  four 
inches  above  the  pubis  it  enters  the  sheath  of  the  rectus,  and 
divides  into  branches  which  ascend  in  this  muscle  to  the 
umbilicus,  and  inosculate  with  the  mammary  artery. 

[Varieties.  The  external  iliac  artery  has  been  seen  to  arise  di- 
rectly from  the  end  of  the  aorta  ;  it  rarely  gives  off  any  branches,  ex- 
cept  the  two  mentioned.  I  have,  however,  several  times  seen  one  or 
more  branches  from  it,  distributed  upon  the  psoas  magnus  muscle. 
The  circumflex  artery  is  sometimes  double,  and  sometimes  arises  from 
the  upper  part  of  the  femoral  artery.  The  epigastric  artery  some, 
times  arises  an  inch  or  even  two  inches  above  Poupart's  ligament. 
It  often  arises  by  a  common  trunk  with  the  obturator,  and  sometimes 
it  is  a  branch  of  that  artery.  It  may  also  arise  from  the  femoral,  or 
the  deep  femoral  artery.] 

The  femoral  artery,  or  the  continuation  of  the  external 
iliac,  descends  obliquely  inwards  from  the  middle  of  the 
crural  arch,  along  the  anterior  and  internal  part  of  the 
thigh,  covered  superiorly  by  the  skin,  superficial  fascia, 
inguinal  ganglia*  and  fascia  lala ;  in  the  middle  of  the  thigh 
it  Is  also  covered  by  the  sartorius,  and  beneath  this  by  a 
strong  aponeurosis  connecting  the  vastus  internus  to  the 
tendons  of  the  adductor -longus  and  magnus; at  the  inferior 
part  of  the  middle  third  of  the  thigh,  it  passes  obliquely 
backwards  through  a  tendinous  opening,  bounded  exter- 
nally by  the  vastus  internus,  internally  by  the  adductor 
magnus,  superiorly  by  the  adductors  magnus  and  longus, 
and  inferiorly  by  the  adductor  magnus  and  vastus  internus  ; 
the  femoral  artery  first  passes  over  the  psoas  and  iliacus, 
next  over  the  pectinasus  and  short  adductor,  from  which  it 
is  separated  by  a  quantity  of  cellular  membrane  and  by 
small  vessels,  it  next  passes  over  the  tendon  of  the  ad- 
ductor longus  ;  the  femoral  vein  descends  along  with  it,  at 
first  internal,  afterv/ards  posterior  to  it ;  the  anterior  crural 
nerve  is  external  to  it,  two  or  three  of  its  branches  are  very 


DUBLIN    DISSECTOR  401 

near  it,  above  the  middle  of  the  thigh,  one  small  nerve 
crosses  the  artery,  and  the  saphenus  nerve  descends  in  its 
sheath  along  the  forepart  of  the  vessel ;  it  sends  off,  1st, 
three  or  four  superficial  branches,  viz. : — inguinal  branches 
to  the  inguinal  ganglia,  &c. ;  the  superficial  pudic,  one  or 
two  in  number,  which  pass  towards  the  pubis  and  are  lost 
in  the  integuments ;  the  superficial  epigastric,  the  longest  and 
largest  of  these  branches,  ascends  obliquely  inwards  to- 
wards the  umbilicus,  parallel  to  the  internal  epigastric,  and 
is  lost  in  the  integuments  ;  the  external  circumflex  ilii  extends 
along  Poupart's  ligament  to  the  crest  of  the  ilium,  where 
it  terminates  in  the  skin ;  2nd,  the  profunda  is  the  largest 
branch  of  the  femoral,  it  arises  about  two  inches  below  the 
crural  arch,  from  the  outer  and  back  part  of  the  femoral 
artery,  bends  a  little  outwards  at  first,  then  descends  ob- 
liquely inwards  and  backwards  behind  the  femoral  artery, 
and  the  tendon  of  the  adductor  longus,  passing  over  the 
psoas,  crurseus,  and  adductor  brevis,  at  the  back  part  of  the 
thigh  it  terminates  in  two  branches  for  the  hamstring  mus- 
cles ;  in  this  course  it  gives  off  the  two  circumflex,  and  the 
three  perforating  branches;  the  external  circumflex  artery, 
arises  from  the  outer  part  of  the  profunda,  passes  trans- 
versely beneath  the  sartorius  and  rectus  muscles,  and  di- 
vides into  three  fasciculi  of  branches,  superior,  middle,  and 
inferior  ;  the  first  ascend  along  the  tensor  vaginae  and  glu- 
trcus  medius  muscles,  and  inosculate  with  the  glutseal  ar- 
tery ;  the  second  pass  round  the  bone  to  its  back  part,  and 
inosculate  with  the  glutasal,  sciatic,  and  internal  circumflex 
arteries ;  the  third  are  the  longest  and  largest  branches, 
they  descend  towards  the  knee  and  supply  the  extensor 
muscles.  The  internal  circumflex  artery  arises  sometimes 
below,  sometimes  above  the  preceding,  it  often  proceeds 
from  the  femoral  itself,  it  passes  backwards  between  the 
psoas  and  pectinseus,  along  the  obturator  externus  tendon, 
to  the  back  part  of  the  thigh,  first  sending  off  several 
branches  to  the  surrounding  muscles,  and  to  the  hip  joint, 
also  some  to  inosculate  with  the  obturator  artery  ;  at  the 
back  of  the  thigh  it  gives  several  branches  to  the  gemelli, 
quadratus,  glutseus  maximus,  and  the  hamstring  muscles, 
and  inosculates  with  the  external  circumflex  and  sciatic 
arteries ;  the  first  or  superior  perforating  artery  passes  back- 
wards beneath  the  lesser  trochanter,  between  the  pectinreus 
and  adductor  brevis,  and  through  the  adductor  magnus,  its 
branches  are  distributed  to  the  latter  and  to  the  hamstring 
muscles  ;  the  second  or  middle  perforating  artery,  larger  than 
the  first,  passes  through  the  adductor  brevis  and  magnus, 
and  spreads  its  branches  among  the  muscles  on  the  back 
of  the  thigh  ;  the  third  or  inferior  perforating  artery  descends 


402  DUBLIN    DISSECTOR. 

behind  the  adductor  longus,  and  through  the  magnus  to  the 
hamstring  muscles ;  on  the  back  part  of  the  thigh  the  pro- 
funda  ends  in  two  branches,  one  passes  to  the  biceps,  the 
other  to  the  semi-membranosus. 

After  the  origin  of  the  profunda,  the  femoral  gives  off  se- 
veral small  muscular  and  cutaneous  twigs,  and  near  the 
opening  in  the  triceps,  through  which  it  passes,  it  gives  off, 
3rd,  the  anastomotica  magna;  this  descends  in  front  of  the 
adductor  tendon  to  the  knee,  sends  several  branches  to  the 
integuments,  vastus  internus,  and  to  the  patella ;  these  in- 
osculate with  the  long  branches  of  the  external  circumflex 
artery  above,  and  with  the  articular  arteries  below. 

[Varieties.  The  femoral  artery  usually  gives  off  the  profunda  at 
an  inch  and  a  half  or  two  inches  below  Poupart's  ligament,  but  the 
bifurcation  may  take  place  at  any  point  above,  even  directly  under 
the  ligament,  and  in  some  rare  cases  the  external  iliac  itself  bifur- 
cates above  Poupart's  ligament,  so  as  to  form  the  femoral  and  pro- 
funda arteries.  Sometimes  the  femoral  artery  divides  at  Poupart's 
ligament  into  three  branches,  the  third  being  the  internal  circumflex 
artery.  Very  rarely  this  artery  divides  high  up,  and  the  two  branches 
again  unite  in  the  popliteal  space; one  of  the  external  pudic.s  some- 
times cornes  off  from  the  deep  femoral,  and  sometimes  one  of  them 
gives  off  the  superficial  epigastric.  The  number  of  branches  coming 
off  from  the  profunda,  is  variable,  and  sometimes  its  branches  are  de- 
rived from  the  femoral  artery  by  two  or  three  distinct  trunks.  The 
external  circumflex  artery  sometimes  arises  directly  from  the  femo- 
ral, and  the  same  is  true  of  the  internal  circumflex  ;  which  also  some- 
times arises  from  the  external  iliac.  The  perforating  arteries  are 
Bornetimes  four  in  number,  while  at  other  times  they  arise  by  a  single 
trunk,  which  then  subdivides.] 

The  popliteal  artery  descends  from  the  inner  side  of  the 
femur,  obliquely  outwards  to  the  inferior  and  central  part 
of  the  popliteal  space  ;  it  is  covered  by  the  skin  and  fascia, 
and  overlapped  superiorly  by  the  semi-membranosus,  and 
inferiorly  by  the  gastrocnemius  and  plantaris  muscles  ;  the 
popliteal  vein  lies  superficial  and  external  to  it;  the  sciatic 
nerve  is  still  more  superficial  and  external ;  its  branches 
are,  1st,  several  muscular  branches  to  the  hamstring  mus- 
cles, and  to  the  gastrocnemius  ;  2nd,  superior  articular,  en- 
circle the  lower  extremity  of  the  femur,  turn  round  the 
sides,  to  the  forepart  of  the  joint,  and  communicate  with  the 
anastomotica  and  with  the  branches  of  the  external  circum- 
flex ;  3rd,  azygos  [or  middle]  articular,  passes  forwards  through 
the  posterior  ligament  of  the  joint,  aud  supplies  the  syno- 
vial  membrane"  and  the  adipose  substance  in  its  cavity ; 
4th,  inferior  articular  arteries,  encircle  the  lower  part  of  the 
joint ;  the  internal  passes  round  the  head  of  the  tibia,  the 
external  is  beneath  the  external  lateral  ligament ;  these  ar- 
teries pass  round  the  joint  to  its  forepart,  inosculate  with 


DUBLIN    DISSECTOR.  403 

the  preceding  and  with  the  anterior  tibial  recurrent ;  [5th, 
the  sural  or  gastrocnemial  arteries,  are  two  branches,  which 
are  extensively  distributed  upon  the  gastrocnemius  mus- 
cle.] At  the  lower  part  of  the  ham  the  popliteal  divides 
into  the  anterior  and  posterior  tibial  arteries. 

The  anterior  perforates  the  inter-osseous  space  close  to 
the  head  of  the  fibula,  descends  obliquely  forwards  along 
the  inter-osseous  membrane  and  over  the  lower  part  of  the 
tibia,  the  synovial  membrane  of  the  ankle,  and  the  supe- 
rior and  internal  part  of  the  tarsus  to  the  first  inter-osseal 
space ;  in  the  leg  it  is  overlapped  by  the  tibialis  anticus 
internally,  by  the  extensor  communis  and  extensor  pollicis 
externally ;  it  passes  beneath  the  annular  ligament  of  the 
ankle;  on  the  tarsus  it  is  covered  by  the  skin  and  by  the 
internal  tendon  of  the  extensor  brevis ;  it  is  accompanied 
by  two  veins;  the  anterior  tibial  nerve  descends  superficial 
and  external  to  it ;  it  gives  off,  1st,  the  recurrent,  which 
passes  upwards  and  inwards,  and  is  lost  around  the  articu- 
lation of  the  knee  ;  2nd,  muscular  branches,  very  numerous, 
to  the  muscles  on  the  outer  and  anterior  part  of  the  leg  ; 
iird,  malleolar  brandies,  which  ramify  on  the  external  and 
internal  malleoli ;  on  the  former  they  inosculate  with  the 
anterior  peronceal ;  4th  and  5th,  tarsal  and  metatarsal,  are 
distributed  to  the  bones  and  ligaments  of  the  tarsus  and 
metatarsus ;  between  the  two  first  metatarsal  bones  it  di- 
vides into,  6th  and  7th,  the  arteria  pollicis  and  the  communi- 
cans  :  the  former  supplies  the  integuments  of  the  great  toe; 
the  latter  the  first  inter-osseal  muscle,  and  inosculates  with 
the  plantar  arteries. 

[Varieties.  The  anterior  tibial  artery  is  sometimes  very  small,  or 
even  entirely  wanting,  and  its  place  is  then  supplied  by  branches 
from  the  posterior  tibial  and  peroneal  arteries ;  when  this  artery  is 
small,  that  part  of  it  on  the  dorsum  of  the  foot  called  the  dorsal  ar- 
tery, is  supplied  by  the  anterior  peroneal  artery,  which  is  then  very 
large,  while  the  tibial  is  either  lost  upon  the  lower  part  of  the  leg,  or 
else  anastomoses  with  the  dorsal  branch  of  the  peroneal ;  the  exter- 
nal plantar  artery  is  sometimes  continued  on  to  the  dorsum  of  the 
foot,  to  supply  the  place  of  a  small  anterior  tibial.  The  anterior  tibial 
sometimes  gives  oft'  a  large  branch,  above  the  ankle,  which  descend, 
ing  gives  off  the  internal  malleolar  artery,  and  finally  anastomoses 
with  the  dorsal  artery  of  the  foot.  The  malleolar,  and  tarsal  arteries 
present  varieties  as  to  their  points  of  origin  and  sometimes  the  one  or 
the  other  of  them  is  wanting.] 

The  posterior  tibial  artery  descends  obliquely  inwards  be- 
tween the  superficial  and  deep  layer  of  muscles  on  the 
back  of  the  leg,  to  the  space  between  the  heel  and  inner 
ankle,  where  it  divides  into  the  internal  and  external  plan- 
tar arteries  ;  it  is  covered  by  the  gastrocnemius  and  solreus, 


404  DUBLIN    DISSECTOR. 

and  lies  on  the  tibialis  posticus,  flexor  communis,  and  infe- 
riorly  on  the  tibia  ;  it  is  accompanied  by  two  veins,  and  by 
the  posterior  tibial  nerve,  which  lies  to  its  external  side  ;  it 
gives  off,  1st,  several  muscular  branches  to  the  deep  and 
superficial  muscles ;  2nd,  the  peronaal  artery  arises  about 
an  inch  below  the  popliteal,  descends  obliquely  outwards 
towards  the  external  ankle,  between  the  fibula  and  flexor 
pollicis ;  sends  numerous  branches  to  the  muscles  of  the 
leg,  and  about  two  inches  above  the  ankle  divides  into  the 
anterior  and  posterior  peronaal  branches  ;  the  former  pierces 
the  inter-osseous  ligament,  and  inosculates  with  the  exter- 
nal malleolar  ;  the  latter  spreads  its  branches  on  the  outer 
side  of  the  heel  and  of  the  foot ;  between  the  heel  and  inner 
ankle  the  posterior  tibial  divides  into  the  internal  and  ex- 
ternal plantar  ;  the  internal  plantar  proceeds  along  the  in- 
ternal side  of  the  sole  of  the  foot,  supplying  the  muscles 
and  integuments  of  the  great  toe,  and  inosculating  with  the 
adjacent  vessels  both  on  the  dorsum  and  in  the  sole  of  the 
foot ;  the  external  plantar,  much  larger  than  the  preceding, 
passes  forwards  and  outwards  above  the  flexor  digitorum 
brevis,  as  far  as  the  fifth  metatarsal  bone  ;  it  then  bends 
across  the  metatarsus,  along  the  transversalis  pedis,  as  far 
as  the  first  metatarsal  bone,  where  it  joins  the  anterior 
tibial,  and  thus  forms  the  plantar  arch,  from  which  proceed 
numerous  muscular  branches,  and  the  digital  arteries ; 
these  last  arise  from  the  anterior  or  convex  edge  of  the 
arch,  pass  forwards,  supplying  the  lumbricales  and  inter- 
ossei  muscles,  and  divide  each  into  two  branches  to  supply 
the  opposite  sides  of  the  toes. 

[Varieties.  The  posterior  tibial  artery  is  sometimes  very  small,  and 
its  place  is  then  supplied  by  the  peroneal  artery,  whose  calibre  is  in 
inverse  ratio  to  that  of  the  tibial  arteries.  The  posterior  tibial  and 
peroneal  arteries  sometimes  form  a  large  common  trunk,  to  within 
two  or  three  inches  of  the  ankle  joint  when  they  separate.  The  pe- 
roneal artery  is  sometimes  wanting,  and  its  place  is  supplied  by  small 
branches  from  the  posterior  tibial.  The  anterior  peroneal  artery  is 
sometimes  given  off  by  the  posterior  tibial,  a  short  distance  above  the 
ankle  joint,  the  posterior  peroneal  having  been  given  off  as  usual ; 
this  last  artery  sometimes  supplies  the  two  plantar  arteries,  the  poste- 
rior tibial  being  in  that  case  very  small.  The  dorsal  artery  of  the 
foot,  and  its  branches,  as  already  stated,  are  sometimes  derived  from 
the  peroneal.  There  are  several  varieties  in  the  arrangement  of  the 
plantar  arteries,  and  formation  of  the  plantar  arch.  Sometimes  the 
external  plantar  artery,  supplies  all  the  digital  branches,  at  other 
times  the  two  plantars  enter  equally  into  the  formation  of  the  plantar 
arch :  in  some  cases  the  internal  plantar  artery  takes  the  place  of 
the  external  plantar,  which  is  then  small,  and  in  other  cases,  the  latter 
artery  is  very  large,  and  supplies  the  place  of  the  dorsal  artery  of  the 
foot. 


DUBLIN    DISSECTOR.  405 

In  concluding  the  description  of  the  arterial  anomalies,  it  is  proper 
to  state  that  almost  all  the  departures  from  the  normal  arrangement, 
are  analogous  to  the  natural  distribution  of  the  vessels  in  inferior  ani- 
mals ;  also  that  I  am  led  to  believe  that  varieties  in  the  arterial  dis- 
tribulion  are  much  more  frequent  in  the  negro,  than  in  the  white  sub- 
ject,  at  least  such  is  the  opinion  of  many  practical  anatomists  of  the 
present  day,  and  such  is  my  own  impression  although  I  have  not 
those  certain  data,  which  can  only  be  obtained  by  the  numerical 
method  of  investigation.] 


SECTION  II. 


ANATOMY    OF    THE    VEINS. 

IN  addition  to  the  veins  which  accompany  the  arteries, 
the  relative  situations  of  which  have  been  already  consi- 
dered, there  are  also  several  veins  which  run  independent 
of  these,  and  take  a  superficial  or  subcutaneous  course.  It 
is  impossible  to  fix  the  exact  point  at  which  a  vein  com- 
mences ;  it  is  generally  considered  that  the  arteries  having 
terminated  in  minute  ramifications  or  capillaries,  the  veins 
commence  from  these,  so  that  in  reality  each  vein  is  a  re- 
turning artery,  only  altered  in  structure ;  some  veins  are 
said  to  commence  from  cells,  as  in  the  spleen  and  corpora 
cavernosa  penis  ;  we  shall  describe  the  veins  then  as  pro- 
ceeding from  the  extreme  parts  of  the  body  towards  the 
centre  or  towards  the  heart ;  and  1st, 

The  veins  of  the  head  and  neck ;  the  small  arteries  which 
ramify  on  the  side  and  fore  part  of  the  scalp  are  accom- 
panied each  by  two  veins,  these  all  terminate  in  the  temporal 
veins,  which  sink  into  the  parotid  gland,  and  there  join  the 
internal  maxillary  vein,  which  is  formed  by  the  confluence 
of  the  several  small  veins  which  accompany  the  branches 
of  the  internal  maxillary  artery ;  the  union  of  these  two 
veins  is  the  commencement  of  the  external  jugular  vein, 
which  descends  a  little  backwards  nearly  parallel  to  the 
fibres  of  the  platysma,  across  the  sterno-mastoid  muscle, 
and  at  a  little  distance  above  the  clavicle  enters  the  sub- 
clavian  vein,  or  some  of  its  branches  ;  near  the  angle  of  the 
jaw  this  vein  receives  a  branch  from  the  facial  vein,  and 
in  its  course  down  the  neck  it  is  joined  by  several  cutane- 
ous branches  ;  it  also  not  unfrequently  communicates  with 
the  internal  jugular  vein  by  one  or  two  small  branches  near 
the  os  hyoides. 


406  DUBLIN    DISSECTOR. 

[Varieties,  The  external  jugular  vein,  is  sometimes  double,  either 
because  the  branches  which  form  it,  do  not  unite  until  they  reach  the 
lower  part  of  the  neck  ;  or  because  it  gives  off  above  a  small  collateral 
branch,  which  again  empties  into  it  below  ;  or,  lastly  because  it  bi- 
furcates, before  it  empties,  into  the  subclavian  vein.  The  branches 
which  form  this  vein  are  uncertain,  although  usually,  those  mentioned 
above  ;  hence  its  size  is  variable  and  often  differs  on  the  two  sides  of 
the  neck,  as  a  general  rule  however  its  calibre  is  in  inverse  ratio,  to 
that  of  the  other  jugular  veins. 

The  anterior  jugular  vein.  This  vein  collects  the  blood  from  the 
fore  part  of  the  neck,  in  the  supra-hyo ideal  region  and  then  descends 
superficially  near  the  median  line,  to  the  lower  part  of  the  neck, 
where  it  passes  behind  the  sterno-mastoid  muscle  and  empties  into 
the  subclavian  vein,  either  by  itself,  or  in  common  with  the  external 
jugular ;  the  vein  on  one  side,  is  usually  larger  than  the  other,  some- 
times  there  is  but  one  and  again  both  may  be  wanting  ;  these  veins 
anastomose  with  each  other  and  with  the  external  and  internal  jugu- 
lar veins  ;  their  calibre  is  in  inverse  ratio  to  that  of  the  external  jugu- 
lars, which  they  sometimes  exceed  in  size  ;  the  branches  by  which 
they  are  formed  are  irregular.  (For  the  sinuses  of  the  dura  mater, 
See  page  285.)] 

The  internal  jugular  vein  commences  in  the  foramen  lace- 
rum  posterius  basis  cranii,  from  the  termination  of  the  late- 
ral sinus,  it  descends  along  the  outer  side  of  the  carotid 
artery,  receives  the  facial,  laryngeal,  and  several  muscular 
veins,  and  opposite  the  sternal  end  of  the  clavicle  joins  the 
subclavian  vein. 

[This  vein  receives  the  blood  from  the  cavity  of  the  cranium  and 
most  of  the  head  and  face  ;  its  calibre  is  generally  unequal  on  the 
two  sides ;  sometimes  it  is  very  small  on  one  side,  the  external  jugu- 
lar in  that  case  being  unusually  developed ;  they  are  always  in  inverse 
ratio,  this  is  owing  to  the  fact  that  the  facial  vein  returning  all  the 
blood  from  the  exterior  of  the  face,  and  other  veins,  in  one  subject 
empty  into  the  internal,  in  another  into  the  external  jugular  vein.] 

The  veins  of  the  upper  extremity  are  superficial  and  deep, 
the  superficial  are  the  cephalic,  basilic  and  median. 

The  cephalic  vein  commences  on  the  outer  and  back  part 
of  the  carpus  from  the  junction  of  the  several  dorsal  veins 
of  the  hand,  it  ascends  along  the  radial  side  of  the  fore  arm 
to  the  bend  of  the  elbow,  is  there  joined  by  the  median 
cephalic,  it  then  continues  to  ascend  along  the  outer  side 
of  the  biceps ;  near  the  shoulder  it  turns  forwards  and 
passes  towards  the  clavicle  between  the  pectoral  and  del- 
toid muscles,  and  then  sinks  deep  to  join  the  axillary  vein. 

The  basilic  vein  commences  near  the  lower  end  of  the 
ulna,  one  branch  from  the  little  finger  is  named  the  vena 
salvalella,  the  others  are  irregular  in  number  and  size,  it 
ascends  along  the  ulnar  side  of  the  fore  arm,  before  the  in- 
ternal condyle,  where  it  is  joined  by  the  median  basilic 


DUBLIN    DISSECTOR.  407 

vein,  it  then  continues  to  ascend  along  the  inner  side  of  the 
arm,  accompanying  the  brachial  vessels,  and  near  the 
axilla  it  joins  one  of  the  vena?  eomites  or  the  axillary  vein 
itself. 

The  median  vein  arises  a  little  above  the  wrist,  ascends 
along  the  middle  of  the  fore  arm  to  the  bend  of  the  elbow, 
it  here  divides  into  two  branches,  one  (median  basilic)  joins 
the  basilic  vein,  the  other  (median  cephalic)  joins  the 
cephalic  vein,  sometimes  a  third  branch  joins  one  of  the 
deep  veins. 

[The  superficial  veins  of  the  superior  extremity  particularly  on  the 
fore  arm,  present  many  varieties  which  need  not  be  specially  de- 
scribed ;  the  median  vein  may  be  double,  or  it  may  be  wanting  ;  the 
cephalic  vein,  or  radial  as  it  is  called,  on  the  fore  arm,  may  be  double, 
while  above  the  elbow  it  may  be  very  small.  With  the  normal  ar- 
rangement of  the  veins  at  the  bend  of  the  elbow,  the  median  cephalic, 
is  usually  the  preferable  vein  for  the  operation  of  venesection,  as  there 
we  avoid  those  dangers  which  render  it  objectionable,  to  bleed  in  the 
median  basilic.  These  dangers  are  three,  we  may  divide  or  puncture 
the  filaments  of  the  internal  cutaneous  nerve,  which  lie  before  and 
behind  the  vein,  or  we  may  transfix  the  vein  and  puncture  the  brachial 
artery  which  usually  lies  directly  beneath  it,  or  we  may  puncture  the 
tendon  of  the  biceps  flexor  muscle,  thus  giving  rise  to  an  inflamma- 
tion, which  may  prove  troublesome.] 

The  deep  veins  accompany  the  brachial  artery  and  its 
branches  in  the  arm  and  fore  arm,  two  with  each ;  these 
end  in  the  axillary  vein,  which  ascends  in  front  of  the  artery, 
receives  the  thoracic  veins,  passes  beneath  the  clavicle,  and 
is  then  named  subclavian  vein ;  this  passes  inwards,  over  the 
anterior  scalenus,  receives  several  veins  from  the  shoulder 
and  side  of  the  neck,  also  the  external  jugular  and  vertebral 
veins,  and  opposite  the  sterno-clavicular  articulation  unites 
with  the  internal  jugular  vein  to  form  the  vena  innominata, 
which  on  the  right  side  is  a  short  trunk  that  descends  into 
the  thorax  behind  the  sterno-thyroid  muscle,  and  opposite 
the  cartilage  of  the  first  rib  joins  that  from  the  left  side, 
which  is  longer,  and  takes  a  more  transverse  course  as  it 
enters  the  chest,  in  front  of  the  trachea,  and  of  the  arteria 
innominata ;  this  vein  receives  several  branches  from  the 
thyroid  body  and  from  the  anterior  mediastinum.  The 
vena  cava  superior  or  descendens  commences  opposite  the  first 
costal  cartilage  on  the  right  side,  descends  obliquely  in- 
wards in  front  of  the  right  pulmonary  vesselsy  enters  the 
pericardium,  and  opposite  the  third  or  fourth  cartilage  it 
opens  into  the  right  auricle ;  as  it  enters  the  pericardium  it 
is  joined  by  the  vena  azygos,  which  commences  by  a  small 
branch  on  the  first  lumbar  vertebra,  which  often  commu- 
nicates with  the  renal  veins  c1*  with  the  inferior  cava  ;  this 


408  DUBLIN    DISSECTOR. 

vein  then  ascends  through  the  aortic  opening  of  the  dia- 
phragm into  the  posterior  mediastinum,  along  the  right  side 
of  the  dorsal  vertebrae  and  of  the  aorta,  receiving  the  inter- 
costal veins  from  each  side,  also  the  oesophageal  and  bron- 
chial ;  at  the  fourth  vertebra  it  curves  forwards  round  the 
root  of  the  right  lung,  and  opens  into  the  back  part  of  the 
vena  cava :  in  general  a  similar,  only  smaller,  vein  exists 
on  the  left  side  of  the  dorsal  vertebra,  which  receives  the 
left  intercostal  and  bronchial  veins,  and  crosses  the  spine 
opposite  to  about  the  fifth  vertebra,  and  joins  the  right  vena 
azygos,  this  vessel  is  named  the  left  or  lesser  vena  azygos. 

[Varieties.  The  vena  cava  descendens  is  sometimes  though  rarely 
double,  the  two  brachio-cephalic  veins,  or  innominatSB  not  uniting, 
but  descending  separately  to  the  right  auricle  of  the  heart,  this  is  the 
normal  arrangement  in  some  of  the  inferior  animals. 

The  vena  azygos  sometimes  arises  directly  from  the  ascending 
vena  cava,  or  from  the  last  intercostal  or  first  lumbar  vein  ;  this  vein 
does  not  communicate  with  the  renal  vein  as  frequently  as  the  lesser 
a/ygos.] 

The  veins  of  the  lower  extremity  are  superficial  and  deep ; 
the  former  are  the  internal  and  external  saphena  ;  the  exter- 
nal passes  from  the  dorsum  of  the  foot  behind  the  external 
malleolus,  ascends  along  the  back  of  the  leg  to  the  ham, 
and  joins  the  popliteal  vein.  The  internal  saphena  com- 
mences on  the  upper  and  inner  part  of  the  foot,  ascends  in 
front  of  the  inner  ankle  along  the  inner  side  of  the  leg,  and 
behind  the  internal  condyle  of  the  knee ;  it  then  inclines 
to  the  internal  and  anterior  part  of  the  thigh,  and  ascends 
to  within  about  two  inches  of  Poupart's  ligament,  it  then 
passes  through  the  saphenic  opening  in  the  fascia  lata  and 
joins  the  femoral  vein. 

[Varieties.  The  internal  saphena  vein  is  sometimes  double  on  the 
leg  or  thigh,  or  even  in  both  situations,  that  is  it  gives  off  a  large 
collateral  branch,  which  sooner  or  later  again  empties  into  it.  Op- 
posite the  knee  the  external  saphena  vein  sometimes  gives  off  a 
branch,  which  passes  upwards  to  the  front  of  the  thigh  and  empties 
into  the  internal  saphena,  just  before  that  vein  opens  into  the  femoral.] 

The  deep  veins  of  the  leg  accompany  the  arteries,  two  with 
each,  they  terminate  in  the  popliteal  vein,  which  ascends  su- 
perficial and  external  to  the  artery ;  this  vein  then  receives 
the  name  of  femoral,  and  is  closely  connected  to  the  artery, 
lying  posterior  to  it  below,  and  on  its  inner  side  above ;  this 
then  passes  behind  the  crural  arch  and  becomes  the  exter- 
nal iliac,  which  lies  internal  and  rather  posterior  to  the  ac- 
companying artery;  opposite  the  ilio-sacral  symphysis 
this  is  joined  by  the  internal  iliac  vein,  which  arises  from 
the  union  of  the  several  veins  that  accompanied  the 


DUBLIN    DISSECTOR.  409 

branches  of  the  internal  iliac  artery  ;  the  union  of  the  ex- 
ternal and  internal  iliac  veins  constitutes  the  common  iliac 
which  ascend  on  each  side  towards  the  right  side  of  the 
fourth  lumbar  vertebra,  and  unite  to  form  the  inferior  vena 
cava ;  the  left  common  iliac  vein  is  longer  than  the  right, 
and  runs  obliquely  across  the  spine  ;  both  are  posterior  to 
the  corresponding  arteries.  The  inferior  vena  cava  ascends 
along  the  right  side  of  the  lumbar  vertebras,  on  the  psoas 
muscle,  and  left  crus  of  the  diaphragm,  to  the  liver,  passes 
through  a  groove  in  this  organ  between  the  right  and  mid- 
dle lobes,  and  then  through  the  large  quadrangular  opening 
in  the  tendon  of  the  diaphragm,  perforates  the  pericardium, 
and  opens  into  the  lower  and  back  part  of  the  right  auricle  ; 
it  receives  the  middle  sacral,  the  spermatic,  the  renal,  and 
capsular,  and  lastly  the  hepatic  and  the  phrenic  veins. 

[  Varieties.  Sometimes  the  common  iliac  veins  do  not  unite  to 
form  the  ascending  cava,  until  they  reach  the  level  of  the  renal 
veins.  The  spermatic  vein  of  the  left  side  almost  always  empties 
into  the  left  renal  vein  ;  the  left  renal  vein  itself  generally  passes  in 
front  of  the  aorta,  but  sometimes  it  divides  and  one  branch  goes  in 
front  of  the  aorta,  while  the  other  passes  behind  it ;  anomalies  of  the 
renal  veins  are  very  much  less  common  than  those  of  the  renal  arte- 
ries ;  the  left  renal  vein  sometimes  anastomoses  with  the  superior  me- 
senteric  vein.  The  hepatic  veins  generally  empty  into  the  vena 
cava,  below  the  diaphragm,  but  occasionally  they  perforate  that  organ 
separately  and  empty  above  it.] 

The  vena  portcc.  receives  the  blood  from  all  the  abdominal 
viscera  except  the  kidneys,  bladder,  uterus,  and  [liver];  a 
large  vein  commences  on  the  back  of  the  rectum,  (hamor- 
rhoidal,')  ascends  towards  the  meso-colon,  and  becomes  the 
inferior  mesenteric  vein,  which  accompanies  the  artery  of 
the  same  name ;  about  the  second  lumbar  vertebra  this 
unites  with  the  superior  mesenteric  vein,  which  accompanies 
the  artery  of  that  name  also ;  behind  the  pancreas  this 
trunk  is  joined  by  a  very  large  vein,  the  splenic,  which  re- 
turns the  blood  from  the  spleen,  and  also  receives  the  veins 
from  the  great  and  lesser  curvatures  of  the  stomach,  from 
the  duodenum  and  pancreas ;  this  large  vein  passes  trans- 
versely behind  the  pancreas  and  below  the  splenic  artery  ; 
thus  the  vena  portte  is  formed  by  the  union  of  the  splenic 
and  mesenteric  veins,  in  front,  of  the  aorta,  and  behind  the 
pancreas  ;  it  then  ascends  to  the  right  side,  enclosed  in  the 
lesser  omentum  and  behind  the  hepatic  artery  and  ductus 
choledochus;  in  this  course  it  receives  small  veins  from 
the  omentum,  pancreas,  and  gall-bladder ;  at  the  transverse 
fissure  it  divides  at  right  angles  into  a  right  and  left  branch, 
which  pass  horizontally  for  a  short  distance,  and  form 
what  is  termed  the  sinus  of  the  vena  porta  ;  this  rests  on  the 
35 


410  DUBLIN    DISSECTOR. 

lobulus  caudatus  ;  these  branches  then  enter  the  liver,  and 
ramify  through  its  substance  in  a  transverse  direction  or 
from  its  centre  towards  its  circumference,  along  with  the 
branches  of  the  hepatic  artery  and  duct,  all  of  which  are 
surrounded  by  the  capsule  of  Glisson. 

The  vena  portse  has  no  valves,  whereas  all  the  veins  of 
the  extremities  are  furnished  with  these,  also  the  superfi- 
cial veins  of  the  neck ;  the  deep  veins  of  the  neck,  the  ve- 
na azygos  and  the  pelvic  veins  are  deprived  of  valves ;  the 
coats  of  the  vena  portse  are  more  dense  and  fibrous  than 
those  of  most  other  veins  ;  the  femoral  vein  also  possesses 
such  a  very  dense  structure,  that  when  divided  it  will  often 
remain  open  like  an  a?tery. 


SECTION  III. 


ANATOMY  OF  THE  LYMPHATIC  SYSTEM. 

THE  lymphatic  vessels  have  a  great  resemblance  to  veins, 
they  are  furnished  with  numerous  valves,  and  are  arranged 
in  two  sets,  a  superficial  and  deep ;  both  of  these  accom- 
pany the  Veins,  that  is,  proceed  from  the  extreme  parts  to- 
wards the  centre,  the  greater  number  terminate  in  the  tho- 
racic duct,  some  however  end  in  the  veins  on  the  right 
side,  and  recent  observations  seem  to  prove,  that  in  diffe- 
rent situations  the  lymphatic  and  venous  system  are  more 
closely  allied  than  was  formerly  believed  ;  the  lymphatics 
are  extremely  minute,  in  some  situations  they  cannot  be 
demonstrated,  as  in  the  brain,  in  such  probably  the  veins 
perform  the  additional  office  of  absorption  ;  it  is  uncertain 
in  what  manner  these  vessels  commence,  whether  by  open 
mouths  in  the  different  structures,  or  whether  they  are  fine 
returning  arteries,  taking  the  same  course  as  the  veins,  and 
only  differing  from  the  latter  in  their  delicacy  of  size,  in 
having  more  numerous  valves,  in  not  transmitting  the  co- 
loured particles  of  the  blood,  and  in  being  connected  with 
the  lymphatic  or  conglobate  ganglia. 

The  lymphatics  of  the  lower  extremities  are  superficial 
and  deep,  the  first  accompany  the  external  and  internal  sa- 
phena  veins ;  those  which  take  the  course  of  the  external 
saphena,  end  in  the  popliteal  ganglia,  wbfere  they  unite 
with  the  deep  lymphatic  vessels  which  take  the  course  of 
the  tibial  and  fibular  veins  and  arteries ;  tne  lymphatics 
which  accompany  the  internal  saphena  vein  ascend  to  the 


DUBLIN    DISSECTOR.  411 

groin,  pass  through  the  inguinal  ganglia,  and  communicate 
not  only  with  all  the  deep  lymphatics  of  the  limb,  but  also 
with  the  superficial  vessels  from  the  abdomen,  perinaeum, 
and  genital  organs ;  the  deep-seated  lymphatics  about  the 
hip  and  the  perineum  accompany  the  branches  of  the  in- 
ternal iliac  artery  and  vein  into  the  pelvis,  where  they  pass 
through  the  pelvic  lymphatic  ganglia ;  the  lymphatics  from 
the  inferior  extremities  and  from  the  pelvis  ascend  towards 
the  spine,  form  a  plexus  round  the  iliac  arteries,  and  pass 
behind  the  aorta  close  to  the  vertebrae,  and  terminate  in  the 
receptaculum  chyii,  or  the  commencement  of  the  thoracic 
duct,  into  which  numerous  lymphatic  or  lacteal  vessels 
open  from  the  intestinal  canal.  The  lacteal  or  chyliferous 
vessels  commence  from  open  mouths  on  the  surface  of  the 
intestine,  and  thence  pass  through  the  mesenteric  ganglia, 
increasing  in  size  and  diminising  in  number,  towards  the 
spine.  The  lymphatics  of  the  stomach  take  the  course  of 
the  arteries  of  that  viscus,  also  towards  the  spine,  and  join 
the  thoracic  duct.  The  lymphatics  of  the  liver  are  super- 
ficial and  deep,  the  former  are  very  distinct,  some  pass 
back  towards  the  spine,  others  ascend  along  the  falciform 
ligament,  enter  the  thorax,  and  proceed  through  the  ante- 
rior mediastinum  to  the  thoracic  duct  near  its  termination ; 
the  deep  lymphatics  pass,  some  out  of  the  transverse  fis- 
sure, others  from  the  posterior  edge  of  the  liver  on  the  dia- 
phragm ;  all  then  pass  back  towards  the  spine. 

The  thoracic  canal  commences  on  the  body  of  the  second 
or  third  lumbar  vertebra  by  a  large  dilatation,  named  the 
receptaculum  chyli ;  it  then  ascends  between  the  crura  of  the 
diaphragm  into  the  posterior  mediastinum,  and  is  situated 
on  the  right  of  the  aorta,  on  the  left  of  the  vena  azygos, 
and  behind  the  cesophagus ;  with  these  relations,  it  rises  to 
about  the  fifth  dorsal  vertebra,  and  then  crosses  the  spine 
obliquely  to  the  left  side,  passing  behind  the  oesophagus 
and  the  arch  of  the  aorta ;  it  then  again  ascends,  and  is 
placed  beneath  the  left  pleura  between  the  left  carotid  and 
subclavian  arteries,  and  along  the  left  side  of  the  oesopha- 
gus ;  it  now  rises  into  the  neck,  as  high  as  the  sixth  verte- 
bra, behind  the  carotid  and  thyroid  arteries,  and  jugular 
vein ;  it  then  curves  outwards  and  downwards,  and  opens 
into  the  left  subclavian  vein,  close  to  the  jugular.  Two 
valves  internally  protect  this  opening,  these  are  situated 
one  at  either  side.  The  thoracic  duct  receives  in  its  course 
along  the  thorax  several  branches  from  the  lungs,  the  heart, 
and  the  parietes  of  the  chest ;  in  the  neck,  the  lymphatics 
from  the  left  arm  and  left  side  of  the  head,  face  and  neck 
open  into  it.  The  lymphatics  of  the  upper  extremities  are 
superficial  and  deep,  the  former  accompany  the  sub-cuta- 


412  DUBLIN    DISSECTOR. 

neous  veins  to  the  elbow,  and  a  little  above  the  bend  of  this 
joint  they  pass  inwards  through  a  small  ganglion  that  is  si- 
tuated above  the  inner  condyle ;  they  then  join  the  deep 
lymphatics,  and  ascend  along  the  inner  side  of  the  arm  to 
the  axilla,  pass  through  the  axillary  conglobate  ganglia, 
surround  the  axillary  artery,  and  pass  with  it  beneath  the 
clavicle  into  the  neck,  where  they  are  joined  by  the  lym- 
phatics from  the  neck  and  shoulder.  On  the  left  side  these 
branches  end  in  the  thoracic  duct ;  on  the  right  side  they 
form  a  short  canal,  (called  the  right  or  lesser  thoracic  duct,) 
which  opens  into  the  right  or  left  vena  innominata,  at  the 
upper  part  of  the  anterior  mediastinum. 

[Varieties.  The  thoracic  duct  sometimes  divides  into  many 
branches  which  form  a  sort  of  plexus  ;  sometimes  it  divides  into  two 
unequal  trunks,  which  re-unite  sooner  or  later.  In  some  cases  it  ter- 
minates in  the  left  subclavian  and  internal  jugular  veins  by  several 
trunks  ;  in  others  it  bifurcates  superiorly  and  one  trunk  terminates  as 
usual,  while  the  other  empties  into  the  right  subclavian  vein,  uniting 
with  the  right  duct.  Sometimes  the  thoracic  duct  empties  into  the 
right  subclavian  vein,  and  then  the  lesser  duct  is  formed  on  the  left 
side.  Again  this  duct  occasionally  empties  into  the  vena  azygos, 
which  is  said  to  be  its  normal  termination  in  some  mammalia.] 

Arteries,  veins,  and  lymphatics,  are  composed  of  tunics 
whose  number  and  properties  differ  in  each  class :  arteries 
and  some  veins  possess  three  laminse,  but  most  veins  and 
all  the  absorbent  system  have  only  two.  The  first  or  inter- 
nal coat  is  common  to  all  vessels,  it  is  smooth,  polished,  and 
moistened  with  a  fine  unctuous  exhalation  to  favour  the 
course  of  the  contained  fluid,  it  bears  much  resemblance 
to  serous  membrane,  though  in  many  respects  it  differs 
from  this  tissue  ;  in  the  veins  and  lymphatics  it  is  thrown 
into  numerous  semilunar  folds  or  valves,  also  at  the  com- 
mencement of  the  two  great  arteries.  The  second  or  mid- 
dle coat  is  very  distinct  in  the  arteries,  also  in  some  of  the 
large  veins,  it  is  absent  in  the  greater  portion  of  the  venous 
and  in  all  the  absorbent  system ;  it  consists  of  circular 
fibres  which  are  yellowish,  dry,  brittle  and  elastic ;  in  the 
large  veins  they  are  of  a  reddish  brown,  and  softer  than  in 
the"  arteries,  this  coat  possesses  much  elasticity,  it  is  also, 
particularly  in  the  smaller  arteries  contractile,  by  these 
two  properties  it  materially  assists  the  circulation  of  the 
blood ;  by  some  this  has  been  named  the  muscular  coat, 
but  it  is  now  more  generally  denominated  the  fibrous  or 
elastic.  The  third  or  cellular  coat  is  common  to  all  vessels ; 
it  consists  of  cellular  tissue  so  condensed  as  to  appear 
fibrous,  it  has  a  whitish  and  in  some  places  a  yellowish  co- 
lour, it  is  very  elastic,  particularly  in  the  length  of  the  ves- 


DUBLIN    DISSECTOR.  413 

sel ;  it  is  so  closely  connected  to  the  middle  coat  of  the  ar- 
teries as  to  be  difficult  of  separation. 

The  coats  of  vessels  are  well  nourished  by  numerous  ca- 
pillaries from  the  neighbouring  vessels,  these  are  the  "  vasa 
vasorum,"  they  are  also  very  well  supplied  with  nerves 
though  they  are  rather  insensible  to  the  touch,  these  are 
derived  from  the  sympathetic,  the  vagi,  and  in  the  limbs 
partly  from  the  spinal  system. 

ANATOMY   OF   THE   FOZTAL   CIRCULATION. 

THE  umbilical  vein,  which  arises  by  numerous  branches 
from  the  placenta,  and  extends  along  the  umbilical  cord, 
twisted  round  the  umbilical  arteries,  enters  the  umbilicus 
of  the  foetus,  ascends  obliquely  backwards,  enclosed  in  the 
duplicature  of  the  falciform  ligament,  behind  the  linea  al- 
ba, and  the  right  rectus  muscle ;  it  arrives  at  the  notch  in 
the  anterior  edge  of  the  liver,  proceeds  backwards  along 
the  horizontal  fissure,  sending  branches  to  either  side,  par- 
ticularly to  the  left  lobe,  which  at  this  period  of  life  is  of 
considerable  size.  When  the  umbilical  vein  arrives  near 
the  transverse  fissure,  it  divides  into  two  branches ;  the 
right  or  communicating,  the  left  or  the  ductus  venosus ; 
the  right  is  the  larger,  it  passes  transversely  for  about  an 
inch,  and  joins  the  trunk  of  the  vena  portse :  left,  or  the 
ductus  venosus,  ascends  between  the  left  and  Spigelian  lobes 
towards  the  diaphragm,  and  joins  the  middle  hepatic  veins 
just  as  these  are  about  to  join  the  vena  cava.  The  right 
auricle,  distended  with  blood  from  the  superior  and  infe- 
rior vena  cava,  then  contracts  and  propels  its  contents 
partly  into  the  right  ventricle,  but  principally  through  the 
foramen  ovale  into  the  left  auricle.  From  the  right  ventri- 
cle the  blood  is  propelled  into  the  pulmonary  artery ;  this 
vessel  in  the  foetus  divides  into  three  branches,  one  for 
either  lung  small,  and  one  in  the  centre  very  large,  the 
ductus  arteriosus,  this  is  about  half  an  inch  in  length,  passes 
backwards  and  downwards,  and  joins  the  aorta  a  little  be- 
low its  arch;  but  little  blood  passes  through  the  lateral 
branches,  the  principal  portion  passing  through  the  ductus 
arteriosus  into  the  aorta. — That  portion  of  blood  which 
was  transmitted  directly  from  the  right  auricle,  through  the 
foramen  ovale  into  the  left  auricle,  descends  into  the  left 
ventricle,  from  which  it  is  also  propelled  into  the  aorta,  the 
superior  branches  of  which  circulate  the  blood  through  the 
upper  parts  of  the  body,  whence  it  is  returned  to  the  heart 
"by  the  veins  that  form  the  superior  vena  cava.  The  de- 
scending aorta  conveys  the  blood  to  the  abdominal  viscera, 
and  at  the  fourth  lumbar  vertebra  this  vessel  divides  into 
the  external  and  internal  iliac  arteries,  the  former  are  small 
35* 


414  DUBLIN    DISSECTOR. 

in  the  child,  tlje  latter  are  very  large,  and  are  named  the 
umbilical  or  hypogastric  arteries,  these  pass  forwards  and 
upwards  along  the  sides  of  the  bladder,  approach  each 
other,  and  ascend  to  the  umbilicus ;  these  arteries  then 
twine  around  the  umbilical  vein  in  the  cord,  and  arriving 
at  the  placenta  divide  into  numerous  branches,  which  ra- 
mify through  this  organ;  thus  at  this  age  these  arteries 
serve  the  office  of  veins.  The  external  iliac  arteries  de- 
scend as  in  the  adult,  and  the  blood  which  they  circulate 
is  returned  by  the  corresponding  veins.  The  iliac  veins 
unite  at  the  fourth  lumbar  vertebra,  arid  commence  the  in- 
ferior vena  cava,  which  ascends,  and,  as  in  the  adult,  pass- 
es through  the  liver,  is  joined  by  the  hepatic  veins,  and  then 
terminates  in  the  right  auricle  of  the  heart. 

In  connexion  with  the  foetal  heart,  the  student  may  re- 
mark the  thymus  body;  this  body  fills  the  upper  part  of  the 
anterior  mediastinum,  ascending  as  high  as  the  thyroid 
body,  and  descending  in  front  of  the  pericardium,  and  of 
the  great  vessels,  nearly  as  low  as  the  diaphragm  ;  it  con- 
sists of  two  lobes  of  an  oval  figure,  close  in  the  centre,  but 
separated  at  either  end.  It  lies  on  the  trachea,  the  left 
vena  innominata,  the  arch  of  the  aorta,  and  the  pericardium, 
is  covered  by  the  sternum  and  sterno-thyroid  muscles,  and 
is  surrounded  by  a  loose  capsule  of  cellular  membrane. 
It  consists  of  several  small  lobules  which  are  filled  with  a 
whitish  fluid,  these  are  connected  by  fine  cellular  tissue, 
numerous  lymphatics  also  are  on  the  surface  and  penetrate 
the  substance  of  this  body.  Several  organs  in  the  body 
present  peculiarities  in  the  foetus,  these  have  been  already 
noticed  in  the  description  given  of  each  in  the  adult  state. 


PART   IV, 


DESCRIPTION  OF  THE  BONES. 


THE  osseous  structure  is  the  hardest  in  the  body ;  it  is 
composed  chiefly  of  phosphate  of  lime,  with  a  little  carbo- 
nate deposited  in  a  cartilaginous  substance  which  is  per- 
fectly organized  and  well  supplied  with  vessels  for  its 
nourishment  and  growth.  The  bones  present  great  variety 
of  figure :  they  are  commonly  classed  into  the  flat,  long, 
and  irregular. 

[Some  also  make  a  class  of  short  bones,  including  those  of  the 
carpus  and  the  tarsus.] 

They  support  and  protect  the  soft  parts,  give  the  general 
form  to  the  whole  body  as  well  as  to  its  different  parts,  they 
also  serve  as  the  passive  organs  of  locomotion,  affording  a 
series  of  levers  by  means  of  which  the  muscles  effect  the 
various  motions  and  actions  of  the  body. 

When  all  the  bones  are  connected  by  their  ligaments  the 
collection  is  called  a  natural  skeleton;  when  united  by  art, 
an  artificial  skeleton.  The  skeleton :is  divided  into  the  trunk 
and  extremities. 

[A  better  division  of  the  skeleton  is  into  the  head,  trunk  and  ex- 
tremities.] 

The  trunk  consists  of  the  middle  part  and  two  extremities  ; 
the  middle  of  the  trunk  is  formed  by  the  vertebral  column 
and  the  chest ;  the  upper  extremity  of  the  trunk  is  the  head, 
the  lower  the  pelvis. 

The  vertebral  column  consists  of  twenty-four  vertebrae, 
which  are  divided  into  three  classes  according  to  the  three 
regions,  viz.  seven  cervical,  twelve  dorsal,  and  five  lumbar. 

The  chest  or  thorax  is  formed  before  by  the  sternum, 
which  in  the  adult  consists  of  two  pieces,  with  the  xiphoid 
appendix,  on  either  side  by  the  twelve  ribs,  and  behind  by 
the  dorsal  vertebrae. 


416  DUBLIN    DISSECTOR. 

The  head  comprises  the  cranium  and  the  face  :  the  crani- 
um or  skull  is  composed  of  eight,  or  according  to  some,  of 
eighteen  bones,  viz.  the  frontal,  the  two  temporal,  two  ap- 
rietal,  the  occipital,  the  ethmoid  and  the  sphenoid ;  to  these 
may  be  added  the  ten  following,  viz.  the  two  small  turbi- 
nated  bones  of  the  sphenoid  or  of  Bertin,  and  the  four  au- 
ricular bones  in  each  temporal  bone,  which  have  been  al- 
ready described  in  the  anatomy  of  the  ear. 

The  face  is  divided  into  the  upper  and  lower  jaw  ;  the 
upper  consists  of  thirteen  bones,  viz.  the  two  superior  max- 
illary, two  palatine,  two  lachrymal,  two  nasal,  two  malar, 
two  inferior  turbinated  bones,  and  the  vomer  ;  to  these  may 
be  added  the  sixteen  teeth.  The  lower  jaw  consists  of  the 
inferior  maxillary  bone,  which  contains  sixteen  teeth ;  some 
consider  the  os  hyoides  as  an  appendix  to  the  bones  of  the 
face ;  this  bone,  however,  has  been  already  noticed  in  the 
description  of  the  larynx. 

The  pelvis  is  the  lower  extremity  of  the  trunk  ;  it  con- 
sists of  the  sacrum,  the  ossa  coccygis,  and  the  two  ossa  in- 
nominata. 

The  superior  or  thoracic  extremities  are  composed  each  of 
four  parts,  the  shoulder,  which  consists  of  two  bones,  the 
clavicle  and  scapula  ;  the  arm,  of  the  humerus,  [more  pro- 
perly called  the  os  brachii,  or  bone  of  the  arm  ;  humerus, 
meaning  the  shoulder ;]  the  fore  arm  of  two,  the  radius  and 
ulna ;  and  the  hand,  which  is  subdivided  into  the  carpus, 
metacarpus,  and  fingers.  The  carpus  consists  of  eight 
small  bones :  the  metacarpus  of  five,  and  the  fingers  of 
fourteen,  each  consisting  of  three  phalanges  except  the 
thumb,  which  has  only  two. 

[Besides  which  the  thumb  has  two  ossa  sesamoidea,  at  the  meta- 
carpo-phalangeal  articulation.] 

The  inferior  or  abdominal  extremities  are  each  divided  into 
three  parts  ;  the  thigh,  which  consists  of  but  one  bone,  the 
femur  ;  the  leg,  which  consists  of  three,  the  patella,  tibia, 
and  fibula ;  and  the  foot,  which  is  divided  into  three  parts, 
the  tarsus,  metatarsus,  and  toes  ;  the  tarsus  consists  of  se- 
ven irregular  bones,  the  metatarsus  of  five  long  bones,  and 
the  toes  of  fourteen,  each  consisting  of  three  phalanges, 
except  the  great  toe,  which  has  only  two. 

[In  addition  to  which  the  great  toe  has  two  ossa  sesamoidea,  at  the 
metatarso-phalangeal  articulation  ;  sesarnoid  bones  are  also  frequently 
found  at  other  points  upon  the  hand  and  foot.] 

In  the  adult  skeleton  the  number  of  bones  amounts  to 
two  hundred  and  forty-two,  including  the  bones  of  the  ear 
and  the  teeth,  but  excluding  the  os  hyoides  and  the  sesa- 
moid  bones.  This  number  is,  however,  variously  stated  by 


DUBLIN    DISSECTOR.  417 

different  writers,  some  bones  being  separated  into  more 
parts  by  some  authors  than  by  others. 

THE    VERTEBRJE. 

The  vertebra  are  twenty-four  in  number,  they  belong  to 
the  class  of  irregular  bones,  are  placed  one  above  the 
other,  and  connected  by  ligaments  so  as  to  form  one  solid, 
yet  flexible  column,  placed  in  the  middle  and  back  part  of 
the  trunk,  and  extending  from  the  head  to  the  sacrum. 
The  sacrum  and  coccyx,  from  their  likeness  to  the  true  ver- 
tebra?, have  been  named  the  "false  vertebrae"  All  the 
true  vertebrae  agree  in  the  general  outline,  which  is  as  fol- 
lows :  each  vertebra  consists  of  a  body  and  of  several  pro- 
jections or  processes.  The  body  occupies  the  anterior  cen- 
tral part ;  it  is  thick  and  spongy,  and  rather  circular  or 
oval ;  its  flat  surfaces  above  and  below  give  attachment  to 
the  intervertebral  ligaments ;  the  margin  of  each  is  tipped 
with  a  compact  white  substance;  anteriorly  it  is  trans- 
versely convex  and  very  porous,  posteriorly  concave,  so  as 
to  form  part  of  the  spinal  canal  or  foramen;  this  surface 
is  perforated  by  several  holes  for  vessels.  The  processes 
of  each  vertebra  are  nine,  twoJUiteral  or  the  laminae,  two 
transverse,  four  oblique  or  articulating,  and  one  spinous. 

The  lateral  processes,  or  lamina,  arise,  one  on  each  side  by 
a  sort  of  pedicle  from  the  posterior  part  of  the  body  ;  they 
pass  backwards,  bounding  the  sides  of  the  spinal  hole,  and 
unite  posteriorly  in  the  spinous  process ;  they  are  broad 
behind,  but  narrow  where  they  join  the  body,  being  grooved 
out  above  and  below  into  a  notch  ;  the  inferior  of  these  is 
the  larger ;  these  notches,  when  the  vertebra?  are  joined, 
form  the  intervetebral  holes  for  the  passage  of  the  spinal 
nerves.  The  spinous  process  is  the  most  projecting  part  of 
the  vertebrae  in  the  posterior  median  line  ;  its  base  is  bifur- 
cated, its  apex  generally  ends  in  a  point  or  tubercle.  The 
transverse  processes  arise  from  the  laminse,  and  are  directed 
outwards  on  each  side.  The  articular  or  oblique  processes 
arise  from  the  roots  of  the  transverse,  two  ascend,  two  de- 
scend ;  they  are  covered  with  cartilage,  and  articulate  with 
the  corresponding  processes  of  the  vertebrae  above  and  be- 
low. The  spinal  hole  or  canal  is  bounded  by  the  body  and 
processes ;  it  is  oval  or  triangular.  The  processes  of  the 
vertebrae  are  of  a  more  compact  structure  than  the  bodies, 
which  are  very  light  and  spongy.  A  vertebra  is  generally 
developed  by  three  points  of  hone,  one  for  the  body,  and 
one  on  each  side  for  the  laminse  and  articulating  process- 
es ;  sometimes  a  fourth  point  is  deposited  for  the  spinous ; 
this  process  is  seldom  found  ossified  in  the  foetus,  but  re- 
mains cartilaginous  for  some  time.  In  addition  to  these 


418  DUBLIN    DISSECTOR. 

three  principal  ossific  points,  there  are  frequently  accessory 
points  or  epiphyses  found  in  the  processes,  as  well  as  on 
the  surfaces  of  the  body.  These  are  the  general  charac- 
ters of  all  the  vertebrae,  but  each  of  the  three  classes  pre- 
sents some  peculiarity. 

The  lumbar  vertebrae  are  five ;  these  are  the  largest  in  the 
column  ;  the  body  of  each  is  very  broad  transversely,  com- 
pared with  its  height;  its  upper  and  lower  surfaces  are  flat, 
and  bordered  with  hard  projecting  edges,  which  render  it 
concave  from  above  downwards  on  its  forepart.  The  la- 
mina, are  thick,  broad,  but  short ;  the  notches,  particularly 
the  lower,  are  very  large  ;  the  spinous  process  is  broad,  flat, 
and  square,  and  ends  not  in  a  point,  but  in  a  thick  rough 
border  :  the  articulating  processes  are  oval,  strong,  and  ver- 
tical ;  the  superior  are  concave,  look  inwards  and  a  little 
backwards ;  the  inferior  are  convex,  look  outwards  and  a 
little  forwards ;  are  nearer  to  each  other  than  the  former, 
and  are,  therefore,  received  into  those  of  the  vertebra  be- 
low :  the  transverse  processes  are  long,  thin,  and  horizontal, 
and  more  anterior  than  those  of  the  dorsal  vertebrae,  but 
posterior  to  those  of  the  cervical ;  the  spinal  foramen  is 
triangular,  and  larger  than  in  the  back ;  the  body  of  the 
fifth  lumbar  vertebra  is  cut  off  obliquely  below,  so  as  to  be 
much  deeper  before  than  behind ;  its  transverse  processes 
are  short,  strong,  and  rounded. 

The  dorsal  vertebrae,  are  twelve  in  number,  and  of  an  in- 
termediate size  between  the  cervical  and  lumbar  :  they  de- 
crease from  the  first  to  the  fourth,  and  then  increase  to  the 
last,  so  that  the  fourth  and  fifth  are  the  smallest.  The  body 
is  thicker  behind  than  before,  and  in  most,  longer  from  be- 
fore backwards  than  transversely,  flat  above  and  below, 
and  round,  except  in  the  first,  whose  surfaces  are  heart- 
shaped,  and  very  convex  anteriorly  ;  on  either  side  it  pre- 
sents two  small  depressions  or  notches,  covered  with  carti- 
lage ;  the  superior  is  the  larger ;  when  the  vertebrae  are 
conjoined  two  of  these  notches  form  an  oval  depression  for 
the  head  of  each  rib ;  the  lamina  are  broad  and  thick ;  the 
notches  are  large  and  anterior  to  the  oblique  processes :  the 
transverse  processes  are  long  and  large,  and  directed  back- 
wards ;  on  the  front  of  each,  near  the  end,  except  of  the 
two  last,  there  is  a  small  depression  covered  with  cartilage 
for  articulating  with  the  tubercle  of  the  rib ;  the  oblique 
processes  are  vertical,  the  superior  directed  backwards,  the 
inferior  forwards  ;  the  spinal  hole  or  canal  is  small  and  oval ; 
the  spinous  processes  are  long,  of  a  prismatic  or  triangular 
form,  bent  downwards  very  much,  or  imbricated,  and  tu- 
bercular at  their  extremities.  The  first  has  the  body  long 
transversely,  arid  on  either  side  a  full  depression  above  for 


DUBLIN    DISSECTOR.  419 

the  head  of  the  first  rib,  and  half  of  a  similar  cavity  below 
for  the  upper  part  of  the  head  of  the  second  rib  ;  its  spi- 
nous  process  is  thick,  long,  and  horizontal,  and  its  articular 
processes  are  oblique  :  the  tenth  has  also  a  full  depression 
on  its  body  for  the  tenth  rib,  the  eleventh  and  twelfth  in 
like  manner,  these  two  last  also  want  the  articulating  de- 
pressions on  the  transverse  processes,  and  they  somewhat 
resemble  the  lumbar  vertebrae,  in  the  shape  of  their  body, 
and  inferior  articular  processes. 

The  cervical  vertebra  are  seven  in  number  and  smaller 
than  the  others ;  their  body  is  long  transversely,  a  little 
deeper  before  than  behind ;  the  lower  surface  is  concave 
from  behind  forwards,  the  upper  is  larger  or  broader,  and 
concave  from  side  to  side  ;  the  structure  is  more  compact 
than  in  the  dorsal  and  lumbar ;  the  lamina  are  long  and 
narrow,  sharp  and  small  superiorly,  round  and  large  infe- 
riorly,  so  as  to  overlap  those  below  ;  the  spinal  hole  is  large 
and  triangular  ;  the  notches  are  small  and  anterior  to  the 
articular  processes  in  all,  except  on  both  surfaces  of  the 
atlas,  and  of  course  on  the  upper  surface  of  the  second ; 
they  are  nearly  of  equal  size  above  and  below  ;  the  spinous 
process  is  short,,  horizontal  and  bifid  ;  the  transverse  process 
is  short,  bifid,- grooved  above  for  the  nerves,  and  perforated 
near  its  base  by  a  round  hole  for  the  vertebral  vessels ;  it 
is  on  a  plane  anterior  to  the  transverse  processes  of  the 
back  or  loins,  and  appears,  on  account  of  its  foramen,  to 
have  a  second  or  anterior  root  from  the  body  of  the  verte- 
bra ;  the  articular  processes  are  oblique,  the  superior  oval, 
slightly  convex,,  look  upwards  and  backwards ;  the  infe- 
rior also  oval,  are  concave,  and  directed  downwards  and 
forwards. 

The  first  cervical  vertebra  or  atlas  differs  from  the  re- 
maining, in  being  a  mere  bony  ring,  without  any  distinct 
body  or  spinous  process,  the  anterior  part  of  this  ring  is 
tubercular  before,  but  presents  posteriorly  a  smooth  and 
concave  oval  articulating  surface  which  receives  the  odon- 
toid process  of  the  second  vertebra ;  the  margin  of  this 
ring  gives  attachment  to  ligaments ;  it  is  round  and  thick 
behind,  with  a  tubercle,  instead  of  spine  for  the  attachment 
of  the  recti  muscles ;  the  spinal  hole  is  very  large  and  di- 
vided into  two  by  the  transverse  ligament,  which  arises  from 
two  tubercles  placed  on  the  inner  side  of  the  superior  arti- 
culating processes ;  the  anterior  portion,  small,  receives 
the  tooth-like  process  of  the  second  vertebra,  the  posterior 
forms  the  spinal  canal ;  the  lamina  are  thick  and  round 
behind,  but,  near  the  articulating  processes  are  grooved 
above  for  the  vertebral  artery  and  first  cervical  or  sub- 
oecipital  nerve,  and  below  for  the  second  cervical  nerve  ; 


420  DUBLIN"    DISSECTOR. 

before  these  notches  are  the  articular  processes,  the  superior 
horizontal,  concave,  oval  from  before  backwards,  look  up- 
wards and  inwards,  and  receive  the  occipital  condyles ; 
the  inferior  are  nearly  flat,  circular,  and  inclined  a  little  in- 
wards and  downwards  ;•  the  transverse  processes  are  long,  and 
end  in  an  obtuse  point,  the  anterior  root  is  slender,  the  pos- 
terior is  long  and  large,  the  hole  between  these  is  larger 
than  in  the  other  vertebras,  and  is  directed  upwards  and 
backwards;  from  this  a  groove  for  the  vertebral  artery 
winds  backwards  round  the  superior  articular  process. 
In  the  adult  the  atlas  is  very  compact;  in  the  foetus  its 
ossification  takes  place  from  five  points,  one  for  the  an- 
terior arch,  two  for  the  posterior,  and  one  for  each  lateral 
part. 

The  axis  or  second  vertebra  is  remarkable  for  the  length 
of  its  body,  which  has  anteriorly  a  central  ridge  between 
two  depressions  for  muscles,  and  from  its  upper  part  there 
rises  by  a  sort  of  a  neck,  a  large,  round,,  dentiform  (odon- 
toid) process,  the  forepart  of  which  is  received  into  the 
small  articulating  cavity  on  the  anterior  arch  of  the  atlas, 
while  posteriorly  it  presents  a  small,  smooth  convexity, 
which  moves  against  the  smooth  surface  of  the  transverse 
ligament  of  the  atlas  ;  the  apex  is  rather  pointed,  to  it  and 
to  the  sides  of  this  process  the  lateral  or  check  ligaments 
are  attached ;  the  lamina  are  very  strong ;  the  superior 
notches  are  behind,  the  inferior  before  the  articular  pro- 
cesses ;  the  spinal  hole  is  large  and  heart-shaped ;  the  spi- 
nous  process  is  forked  and  very  strong,  its  under  surface  is 
channeled  ;  the  superior  oblique  processes  are  slightly  con- 
vex, nearly  horizontal,  and  look  a  little  outwards  ;  the  in- 
ferior are  smaller,  flat,  and  look  downwards  and  forwards ; 
the  transverse  processes  are  short,  arise  from  the  outside  of 
the  superior  articular  processes,  are  bent  downwards,  and 
are  not  bifid  ;  the  hole  is  directed  obliquely  upwards  and 
outwards.  This  vertebra  in  the  foetus  has  an  additional  or 
fourth  point  of  ossification  in  the  odontoid  process.  It  is 
articulated  directly  with  the  atlas  and  third  vertebra,  and 
indirectly  with  the  occipital  bone. 

The  seventh  cervical  vertebra  is  large,  its  spine  is  very 
prominent,  and  not  bifid ;  its  transverse  process  is  seldom 
perforated,  as  in  the  other  cervical  vertebra?  ;  when  there 
is  a  foramen  in  it,  it  transmits  the  vertebral  vein  and  not 
the  artery. 

[I  have  repeatedly  examined  the  seventh  cervical  vertebra  with  a 
view  to  this  point,  and  have  always  found  the  transverse  process 
perforated.  The  vertebral  artery  usually  enters  the  foramen  in  the 
transverse  process  of  the  sixth  vertebra,  but  may  enter  that  of  the 
fifth  or  fourth.  I  have  several  times  seen  two  foramina  in  the  trans- 


DUBLIN    DISSECTOR.  421 

verse  processes  of  the  cervical  vertebras,  one  for  the  vertebral  artery 
and  the  oilier  for  the  vertebral  vein.] 

In  this  vertebra  an  additional  point  of  ossification  is 
found  in  the  pedicle  which  connects  the  processes  to  the 
body ;  this  sometimes  increases  beyond  the  transverse  pro- 
cesses of  the  vertebral  column,  so  as  to  resemble  a  super- 
numerary or  a  cervical  rib. 

The  length  of  the  vertebral  column  is  generally  about  a 
third  of  that  of  the  whole  body  ;  the  lumbar  and  cervical 
regions  are  nearly  equal,  and  each  about  half  the  length 
of  the  dorsal,  the  latter  commonly  measures  twelve  inches, 
and  each  of  the  former  about  six.  Its  general  form  is  that 
of  a  pyramid,  the  base  below ;  but  when  accurately  exa- 
mined it  will  be  found  to  represent  three  pyramids;  the 
first  has  its  apex  in  the  third  cervical  vertebra,  surmounted 
by  the  axis  and  atlas,  and  its  base  is  in  the  first  dorsal, 
which  is  also  the  base  of  the  second  pyramid  whose  apex 
is  in  the  fifth  dorsal,  where  also  is  the  apex  of  the  third 
pyramid,  whose  base  is  at  the  sacrum,  the  vertebrae  dimi- 
nishing in  size  about  the  fourth  and  fifth  dorsal.  The  co- 
lumn is  convex  anteriorly  in  the  neck,  concave  in  the  back, 
and  convex  in  the  loins  ;  these  curvatures  are  caused  part- 
ly by  the  different  thickness  of  the  bodies  of  the  vertebra 
before  and  behind,  but  principally  by  that  of  the  interver- 
tebral  ligaments  in  these  three  situations.  A  perpendiculai 
line  passed  through  the  centre  of  the  apex  and  base  of  the 
column  will  be  found  anterior  to  the  dorsal,  and  posterior 
to  the  cervical  and  lumbar  vertebrae.  In  the  dorsal  region 
there  is  generally  a  lateral  curvature  also,  which  is  usually 
concave  to  the  left  side ;  this  direction  of  this  curve  has 
been  by  some  ascribed  to  the  pressure  of  the  aorta  on  the 
left  side,  by  others,  and  with  more  probability,  to  the  effect 
of  muscular  action,  for  as  the  muscles  of  the  right  arm  are 
the  most  used,  the  points  of  the  spine  to  which  these  are 
attached  will  be  drawn  towards  that  side ;  in  the  several 
violent  exertions  also,  such  as  pulling  forcibly,  the  body  is 
usually  bent  to  the  left  side.  The  column  is  covered  ante- 
riorly by  the  anterior  common  ligament,  and  in  the  neck 
by  the  recti  and  longi  muscles,  in  the  back  by  the  last 
named  muscles  above,  and  below,  by  the  vena  azygos. 
aorta,  &c.,  and  in  the  loins  by  the  crura  of  the  diaphragm, 
the  aorta,  vena  cava,  and  sympathetic  nerves;  posteriorly 
the  column  presents  in  the  median  line,  the  spinous  pro- 
cesses short,  horizontal  and  separate  in  the  cervical  and 
lumbar,  but  close  and  bent  over  one  another  in  the  dorsal 
region  ;  on  each  side  of  these  are  the  vertebral  grooves, 
which  are  wide  in  the  neck,  but  deep  and  narrow  in  tho 
back  and  loins;  these  are  filled  by  tho  extensor  muscles: 
30 


422"  DUBLIN    DISSECTOR. 

the  apertures  between  the  laminae  are  closed  by  the  yellow 
ligaments,  and  covered  by  these  muscles;  outside  these 
grooves  in  the  neck  and  loins  lie  the  oblique  or  articular 
processes,  but  in  the  back  the  transverse  processes,  which 
in  this  region  are  on  a  plane  posterior  to  those  in  the  neck 
and  loins :  the  intervertebral  or  the  holes  of  conjunction  in 
the  dorsal  and  lumbar  regions  are  before  the  transverse 
processes,  but  in  the  neck  between  them  ;  in  the  back  they 
are  behind  the  cavities  for  the  heads  of  the  ribs.  The  spine 
supports  the  head  and  chest,  and  combines  strength  with 
lightness  and  flexibility ;  it  serves  as  the  centre  of  all  the 
motions  of  the  trunk,  and  transmits  the  weight  it  bears  to 
the  sacrum  and  pelvis ;  it  gives  insertion  to  numerous 
muscles,  and  lodges  and  protects  the  medulla  spinalis  in 
the  spinal  canal ;  this  canal  is  large  and  triangular  in  the 
neck  and  loins,  round  and  contracted  in  the  back.  The 
spinal  column  is  nearly  straight  or  perpendicular  in  the 
child  ;  in  the  foetus  the  pyramidal  figure  is  reversed,  the 
base  being  in  the  cervical  and  dorsal  vertebree,  the  apex 
in  the  lumbar  and  sacral. 

[There  are  occasionally  varieties  in  the  number  of  the  vertebrae  ; 
(here  may  be  but  six  cervical  vertebras  ;  there  may  be  eleven  or  thir- 
teen dorsal  vertebrae,  and  usually  there  is  a  corre?ponding  difference 
in  the  number  of  the  ribs ;  and  there  may  be  four  or  six  lumbar  ver- 
tebras, of  which  last  variety  I  have  a  specimen,  which  also  exhibits  a 
etrong  lateral  inclination  of  the  spine.  Tine  transverse  processes  of 
the  last  cervical  and  of  the  first  lumbar  vertebras  are  sometimes  very 
much  developed,  and  even  detached  fiorn  the  rest  of  the  bone,  so  as 
to  resemble  supernumerary  ribs.  The  vertebrae  are  sometimes  bifid,,  or 
the  spinous  process  is  entirely  wanting,  so  that  the  interior  of  the  ca- 
nal is  exposed  ;  this  may  occur  in  the  lumbar  region  only  ;  or  in  ace- 
phalous monsters  it  may  involve  a  few  of  the  cervical  vertebrae,  or 
even  the  whole  column ;  this  anomaly  is  called  spina  bifcta. 

The  vertebras  are  sometimes  fractured,  but  usually  by  violence  so 
great  as  to  cause  immediate  death  :  or  death  may  ensue  from  the 
subsequent  inflammation.  The  operation  of  trepaning  has  been  per- 
formed upofi  a  fracture  of  the  posterior  arch  of  a  vertebra  attended 
with  depression.  The  articulation  of  the  first  and  second  vertebras 
is  occasionally  the  seat  of  dislocation. 

A  great  number  of  muscles  are  at'ached  to  the  vertebrae,  for  exam- 
ple, five  pair  arise  from  the  alias,  the  rcctus  capilis  anticus  minor, 
rectus  capitis  lateralis,  obliquus  capitis  superior,  and  lev  a  tor  anguli 
Bcapulas  from  the  transverse  processes,  and  the  rectus  capitis  poslicus 
minor  from  the  spinous  process;  five  pair  also  are  inserted  into  the 
atlas,  the  lungus  colli  into  its  forepart,  obliquus  capitis  inferior,  sple- 
nius  colli,  and  first  intortransvcrse  into  the  Iransvesse  processes,  and 
the  first  intcrspiuous  into  the  spine. 

From  the  axis  arise  six  pair,  the  rectus  capitis  posticus  major,  ob- 
liquus cupitis  inferior,  multifidus  spinas,  and  first  intcrspinous  from 
the  s-pinous  process,  and  the  levator  anguli  scapulas  arid  first  inter- 


DUBLIN    DISSECTOR.  423 

transverse  from  the  transverse  processes :  five  pair  are  inserted  into 
the  axis,  the  longus  colli  into  its  forepart,  the  splcnius  eolli  and  the 
second  interlransverse  into  the  transverse  processes,  spinalis  colli  and 
second  inierspinous  into  the  spine.  The  muscles  connected  with 
the  other  vertebrEe  more  or  less  extensively,  may  be  arranged  under 
three  groups ;  first,  those  which  arise  from  the  vertebrce  to  be  insert, 
ed  into  other  bones  ;  second,  those  which  arise  from  certain  verte- 
brae to  be  inserted  into  others  ;  and  third,  those  which  arise  from 
other  bones  to  bo  inserted  into  the  vertebra?  ;  and  this  arrangement 
may  be  applied  both  to  those  which  are  situated  posteriorly,  and 
those  anteriorly.  Posteriorly,  they  are  first,  the  trapezius,  latissi. 
rnus  dorsi,  levator  anguli  scapula;,  rhomboidei  major  and  minor:  ser 
rati  postici  superior  and  inferior;  splenius  capitis,  sacro-lumbalis, 
longissimus  dorsi,  trachelo-mastoideus,  cotnplexus,  levatores  costa 
rum  ;  second,  the  splenius  colli,  longissimus  dorsi,  spinalis  dorsi  and 
•colli,  semi-spinalis  dorsi,  transversalis  colli,  mulijfidus  spinas,  inter 
and  supra  spinales  arid  intertransversales  ;  third,  the  cervicalis  as. 
cendens  and  lo-ngissimus  dorsi,  which  last  is  common  to  all  three 
groups. 

Anteriorly  they  are  first  the  rectus  capitis  anticus  major,  scaleni 
anticus,  rnedius,  and  posticus,  the  crura  of  the  diaphragm,  the  psoas 
magnus  and  parvus,  obliquus  intcrnus  and  transversalis  abdominis  ; 
second,  the  longus  colli ;  and  third,  the  quad  rat  as  lurnborum. 

Articulations.  The  vertehree  are  articulated  to  each  other,  to  the 
os  occipitis  above,  to  the  ribs  laterally  on  either  side,  and  to  the  sa- 
crum below.] 

THE   THORAX   OR   CHEST, 

Is  formed  by  the  twelve  dorsal  vertebrae,  already  describ- 
ed, by  the  sternum  and  twelve  pair  of  ribs. 

The  sternum  is  situated  at  the  forepart  of  the  chest,  in  the 
median  line,  and  in  a  direction  from  above  downwards  and 
forwards ;  of  a  flat  and  elongated  form,  broad  above,  nar- 
row in  the  middle,  and  pointed  below;  its  anterior  surface 
is  covered  by  the  skin  and  pectoral  aponeurosis,  is  marked 
by  four  transverse  lines  which  indicate  its  original  division 
into  five  pieces,  the  two  upper  lines  are  most  prominent. 
Although  it  can  be  divided  in  the  adult  into  two  pieces  in 
addition  to  the  xiphoid  cartilage,  we  shall  describe  the 
whole  as  one  bone;  its  posterior  surface  is  smooth  and 
concave,  gives  attachment  to  muscles,  and  looks  towards 
the  anterior  mediastinum;  the  edges  are  thick,  and  present 
seven  depressions  for  the  cartilages  of  the  true  ribs ;  the 
superior  of  these  is  round,  and  the  margin  of  it  is  often 
continuous  with  the  first  costal  cartilage ;  the  remaining 
depressions  are  angular,  and  most  of  them  correspond  to 
the  transverse  lines  or  ridges ;  hence  these  sockets  are  more 
distinct  in  the  young  than  in  the  old  ;  they  are  all  covered 
with  cartilage  and  separated  from  each  other  by  notches. 


424  DUBLIN    DISSECTOR. 

The  upper  or  clavicular  end  of  the  sternum  is  broad,  thick, 
and  concave  from  side  to  side,  for  the  lodgment  of  the  in- 
ler-clavicular  ligament,  and  is  hollowed  out  at  each  angle 
for  articulation  with  the  clavicle,  into  a  shallow  sigmoid 
cavity  covered  with  cartilage  and  directed  outwards  and 
backwards;  this  surface  is  slightly  convex  from  before 
backwards  ;  the  inferior  extremity  is  long  and  thin,  and 
ends  in  a  cartilaginous  epiphysis,  the  xiphoid  or  ensiform 
cartilage;  this  is  sometimes  pointed,  sometimes  bifid,  thick 
or  thin,  turned  forwards  or  backwards,  and  sometimes  per- 
forated by  a  central  hole;  it  remains  cartilaginous  to  a 
late  period  of  life ;  to  it  the  abdominal  muscles  and  the 
costo-xiphoid  ligament  are  attached.  The  sternum  in  the 
foetus  is  separable  into  four  or  five  pieces,  in  the  adult  into 
two,  and  the  ensiform  cartilage  which  is  frequently  ossified 
and  continuous  with  the  lower  portion  of  the  sternum.  The 
upper  piece  is  the  larger  and  thicker  of  the  two,  and  some- 
what square,  its  edges  receive  the  clavicles  and  the  carti- 
lages of  the  first  rib,  and  half  of  those  of  the  second  ;  its 
lower  edge  is  nearly  straight,  and  united  to  the  second 
piece  by  a  cartilage  which  sometimes  admits  of  slight  mo- 
tion between  the  two,  but  which  in  old  persons  is  generally 
found  ossified :  a  foramen  is  sometimes  observed  in  this 
piece  of  the  sternum.  The  second  piece  is  longer  and  nar- 
rower than  the  first,  its  edges  are  marked  by  five  depres- 
sions for  the  five  lower  true  costal  cartilages,  and  at  its  su- 
perior angle  by  half  a  notch,  which  joined  to  a  similar 
notch  in  the  first  piece,  formed  the  cavity  for  the  second 
cartilage  :  the  five  lower  notches  approximate,  and  the  last 
is  frequently  completed  by  the  xiphoid  cartilage.  This 
bone  consists  of  a  very  spongy,  cellular,  and  vascular  tis- 
sue, covered  on  each  surface  by  a  compact  layer. 

[The  sternum  is  sometimes  deficient  either  to  a  considerable  ex- 
tent  or  in  circumscribed  points,  forming  foramina.  I  have  a  speci- 
men exhibiting  two  of  these  perforations,  which  were  closed  up  by 
dense  fibrous  tissue.  This  bone  may  be  fractured,  and  if  depressed, 
the  trephine  and  elevator  may  be  used.  In  the  private  collection  of 
Dr.  J.  Kearny  Rodgcrs,  there  is  an  admirable  specimen  of  fracture 
of  the  sternum,  exhibiting  the  efforts  of  nature  to  produce  a  reunion, 
and  her  partial  success. 

Muscles.  Nine  pair  of  muscles  and  a  single  muscle  are  attached 
to  this  bone,  five  pair  and  the  single  muscle  arise  from  it,  the  sterno- 
mastoid,  sterno-hyoid,  and  sterno.thyroid  superiorly  and  posteriorly  ; 
the  pectoralis  major  from  its  anterior  surface,  the  triangularis  sterni 
from  its  posterior  surface,  and  the  diaphragm  from  the  posterior  sur. 
face  of  the  xiphoid  cartilage;  four  pair  are  inserted  into  it,  the  rec. 
tus  abdominis  into  the  front  of  the  xiphoid  cartilage,  and  the  obliqui 
externua  and  internus,  and  transversalis  abdominis  into  its  edge. 


DUBLIN    DISSECTOR.  425 

Articulations.  This  bone  is  articulated  usually  to  sixteen  bones, 
the  clavicles  and  seven  true  ribs  on  either  side.] 

The  ribs  are  twelve  on  each  side ;  they  extend  in  an 
arched  manner  from  the  vertebrae  towards  the  sternum,  to 
which  the  seven  superior  are  attached  by  the  separate  car- 
tilages  ;  these  are  the  true  or  the  sternal  ribs;  the  five  in- 
ferior do  not  form  complete  circles,  and  are  connected  an- 
teriorly to  each  other,  and  to  the  cartilage  of  the  last  true 
rib,  and  are  named  false ;  the  two  last  of  these  are  some- 
times called  the  floating  ribs ;  the  length  of  the  ribs  gradu- 
ally increases  from  the  first  to  the  eighth,  and  then  diminish- 
es to  the  last;  the  breadth  gradually  diminishes  from 
the  first  to  the  twelfth,  but  in  each  rib  it  is  greatest  near  the 
sternum;  the  first  is  nearly  horizontal,  the  succeeding 
gradually  incline  downwards,  so  as  to  be  lower  before  than 
behind  ;  the  external  surface  of  each  is  convex  and  smooth, 
and  gives  attachment  to  different  muscles ;  the  internal  is 
concave,  and  lined  by  the  pleura;  the  upper  border  is 
round  and  smooth,  and  gives  attachment  to  the  intercostal 
muscles;  the  inferior  is  thin,  and  marked  with  a  groove 
for  the  intercostal  vessels,  which  is  deep  posteriorly  and 
superficial  anteriorly  ;  its  edges  also  give  attachment  to 
the  intercostal  muscles.  The  posterior  end  of  the  rib  pre- 
sents a  head,  neck,  and  tuberosity ;  the  head  is  round,  and 
divided  by  a  ridge  into  two  articular  surfaces,  the  inferior 
of  which  is  the  larger,  these  are  received  into  the  depres- 
sions in  the  dorsal  vertebras ;  an  intervertebral  ligament  is 
attached  to  the  middle  ridge.  The  head  is  supported  by 
the  neck,  which  is  narrow  and  round,  and  lies  in  front  of  the 
transverse  process,  to  which  it  is  connected  posteriorly  by 
the  middle  eosto-trans  verse  ligament.  Beyond  or  external 
to  the  neck  is  the  tubercle,  which  looks  backwards  and  down- 
wards, and  is  divided  into  two  portions  :  the  internal  of  these 
is  smooth  for  articulation  with  the  transverse  process  of  the 
inferior  of  the  two  vertebra?,  to  whose  bodies  the  head  of 
the  rib  is  connected  ;  the  outer  portion  is  rough  for  the  in- 
sertion of  the  external  costo-transverse  ligament.  External 
to  the  tubercle  is  a  rough  line,  which  marks  the  turn  or 
angle  of  the  rib  ;  this  ridge  gives  insertion  to  the  tendon  of 
the  sacro-lumbalis  muscle  ;  it  descends  obliquely  forwards ; 
it  is  close  to  the  tubercle  on  the  first,  but  the  distance  be- 
tween these  increases  in  the  succeeding  ribs  to  the  eleventh  ; 
the  angle  is  not  distinct  on  the  twelfth.  The  anterior  or 
sternal  end  is  thin,  broad,  and  hollowed  into  an  oval  pit  for 
the  insertion  of  the  costal  cartilage.  The  first  rib  is  snorter, 
broader,  and  nearer  the  axis  of  the  chest  than  the  others, 
has  no  angle,  and  therefore  is  not  twisted,  but  represents 
nearly  a  horizontal  semi-circle ;  its  external  surface  is  di- 
3  36* 


426  DUBLIN    DISSECTOR. 

reeled  upwards,  and  is  marked  by  two  grooves  for  the  sub- 
clavian  vein  and  artery,  into  the  intervening  ridge  the  an- 
terior scalenus  muscle  is  inserted ;  the  head  of  this  rib  is 
undivided,  there  is  no  groove,  the  sternal  end  is  very  strong; 
the  eleventh  rib  has  no  groove  or  tubercle,  its  head  is  also 
undivided :  the  twelfth  has  neither  angle,  tubercle,  or 
groove,  and  is  very  short.  The  ribs  are  formed  of  a  cellu- 
lar structure,  covered  by  compact  and  strong  laminae, 
which  often  present  a  scaly  appearance ;  they  are  hard 
and  elastic.  In  the  foetus  each  rib  presents  three  points  of 
ossification,  one  for  the  head,  another  for  the  tubercle,  and 
the  third  for  the  body  or  shaft. 

The  costal  cartilages  are  twelve  in  number;  the  first  is 
very  broad  but  short,  the  length  increases  in  the  succeeding 
to  the  seventh,  and  then  decreases  to  the  last;  the  first 
descends  a  little,  the  second  is  nearly  horizontal,  the  suc- 
ceeding ascend  more  and  more  ;  the  costal  end  of  each  is 
convex,  and  implanted  in  the  rib;  the  sternal  ends  of  the 
seven  superior  are  also  convex,  and  are  received  into  the 
sternum,  those  of  the  three  superior  false  are  blended 
together,  and  those  of  the  two  last  are  pointed  and  unat- 
tached. The  costal  cartilages  are  the  strongest  and  longest 
in  the  body  ;  they  are  flexible  and  elastic,  and  have  a  great 
tendency,  particularly  the  four  or  five  superior,  to  ossifica- 
tion, the  costal  end  is  more  prone  to  this  change  than  the 
sternal ;  they  then  become  opaque  and  very  compact ;  in 
their  natural  state  they  appear  destitute  of  vessels,  nerves, 
or  any  organic  texture,  but  are  enveloped  by  a  vascular 
membrane. 

[Sometimes  there  are  thirteen  ribs  on  each  side,  and  the  supernu- 
merary may  be  ehher  a  cervical  or  a  lumbar  rib;  in  other  cases, 
there  are  but  eleven  ribs  ;  the  costal  cartilages  also  may  be  but  eleven, 
or  there  may  be  thirteen  on  a  side,  even  though  there  are  but  twelve 
ribs,  and  then  the  supernumerary  cartilage  is  lost  in  the  thickness 
of  the  adjoining  muscles,  sometimes  the  anterior  extremity  of  a  rib, 
and  the  adjoining  extremity  of  its  cartilage  are  bifurcated,  circum- 
scribing a  foramen,  closed  by  dense  fibrous  tissue  ;  sometimes  the 
cartilage  of  the  eighth  rib  on  the  left  side  runs  up  to  the  ensiform 
cartilage,  to  the  side  of  which  it  is  articulated  ;  specimens  of  both,  of 
these  anomalies  may  be  seen  in  the  College  Museum. 

Tiie  ribs  may  be  fractured,  and  the  middle  ribs  from  their  position 
are  most  exposed  to  this  accident ;  the  cartilages  may  be  separated 
from  the  ends  of  the  ribs  by  external  violence,  and  they  are  very 
prone  to  be  converted  into  bone,  particularly  in  advanced  life,  the 
ossification  commencing  at  innumerable  points. 

Muscles.  Thirty-three  pair  of  muscles  and  a  single  muscle  are 
attached  to  the  ribs  and  their  cartilages,  but  the  intercoslals  both 
arise  from  and  are  inserted  into  them  ;  thirty-two  pair  and  a  single 
muscle  arise  from  them,  the  sterno-hyoid,  sterno-thyroid,  and  sub- 


DUBLIN     DISSECTOR.  427 

clavius  superiorly,  peet.orales  major  and  minor  anteriorly,  the  exter- 
nal and  internal  int.ercostals  from  their  inferior  edges,  the  transversa- 
lis  abdominis  and  diaphragm  internally,  serratus  magnus  anticus  and 
obliquus  cxternus  laterally,  and  cervicalis  asceridens  and  latissimus 
d'trsi  posteriorly  ;  forty-rive  pair  are.  inserted  into  them,  the  scaleni  an. 
ticus, meditts  and  posticus  superiorly,  the  rectus  abdominis  anteriorly, 
tiie  obliquus  internus  anteriorly  and  inferiorly,  the  external  and  inte"r- 
nal  intercostals  at  their  superior  edges,  triangularis  sterni  internally, 
quadratus  lumborum  inferiorly  and  posteriorly,  serrati  postici  supe- 
rior and  inferior,  sacro  lumbalis,  longissirnus  dorsi,  and  levatores  cos- 
tarum  posteriorly. 

Articulations.  Each  rib  is  articulated  posteriorly  to  the  bodies 
of  two  dorsal  vertebrae,  except  the  first,  eleventh,  and  twelfth,  and 
sometimes  the  tenth;  and  all  except  the  eleventh  and  twelfth  are 
articulated  to  the  transverse  processes  of  the  vertebras.  Anteriorly 
each  rib  is  attached  to  its  cartilage  ;  the  seven  superior  cartilages  are 
attached  to  the  sternum,  the  three  next  to  the  seventh,  and  the  two 
last  are  free.] 

The  thorax,  which  is  composed  of  the  foregoing  bones  and 
cartilages,  resembles,  when  the  arms  are  detached,  a  trun- 
cated cone,  the  base  below,  the  apex  above,  flattened  before 
and  behind;  in  some,  from  the  effect  of  dress,  it  is  of  an 
ovoid  form,  being  contracted  at  the  lower  part  and  wide  in 
the  middle  ;  the  anterior  wall  leads  obliquely  downwards 
and  forwards,  and  is  shorter  than  the  posterior,  which  is 
more  vertical,  and  rendered  very  irregular  by  the  vertebral 
grooves,  and  the  angles  of  the  ribs ;  the  sides  are  convex, 
particularly  behind:  the  intercostal  spaces  are  short,  but 
wide  above,  long  and  narrow  in  the  middle,  and  again  short 
below  ;  they  are  broader  before  than  behind.  The  apex  is 
small,  transversely  oval,  and  very  oblique  from  behind  for- 
wards and  downwards;  it  is  bounded  by  the  first  ribs, 
sternum,  and  vertebral  column;  the  trachea,  oesophagus, 
and  the  cervical  vessels  and  nerves  pass  through  it;  the 
base  is  very  large,  also  transversely  oval,  and  very  oblique 
from  before  backwards  and  downwards,  it  is  bounded  by 
the  xiphoid  cartilage,  the  conjoined  cartilages  of  the  false 
ribs,  and  the  vertebral  column  ;  it  presents  a  great  notch 
anteriorly,  in  which  the  xiphoid  cartilage  is,  and  posterior- 
ly a  small  notch  on  each  side  for  the  vertebral  column. 
The  axis  of  the  chest  is  oblique  from  above  downwards 
and  forwards,  in  consequence  of  the  oblique  direction  of 
the  sternum,  hence  if  a  line  be  made  to  ascend  perpendic- 
ularly from  the  base,  it  will  pierce  the  upper  part  of  the 
sternum ;  and  not  pass  through  the  apex  of  the  cavity. 
The  dimensions,  and  even  the  form  of  the  chest,  vary  in 
different  individuals  and  at  different  ages. 


428  DUBLIN    DISSECTOR. 


THE    PELVIS. 

The  pelvis  is  the  deep  circular  cavity  at  the  lower  end  of 
the  trunk,  bounded  by  the  sacrum,  coccyx,  and  two  ossa 
innorninata  ;  the  latter  in  the  young  subject,  can  be  separ- 
ated each  into  three,  the.iliurn,  ischium,  and  pubis. 

The  sacrum,  in  the  erect  position  of  the  body,  is  placed  at 
the  upper  and  back  part  of  the  pelvis  between  the  last  lum- 
bar vertebra  above,  the  coney x  below,  and  the  ossa  innorni- 
nata on  either  side ;  of  a  triangular  form,  the  base  resem- 
bles a  vertebra,  looks  upwards  and  forwards,  is  very  broad 
transversely,  and  presents  in  the  middle  an  oval  surface  or 
body  cut  off  obliquely  from  before  backwards  and  upwards, 
and  covered  with  cartilage  for  articulation  with  the  last 
lumbar  vertebra,  its  anterior  edge  is  named  the  promonto- 
ry ;  behind  it,  is  the  triangular  aperture  of  the  sacral  or 
spinal  canal,  and  on  each  side  is  a  smooth  .convex  surface 
(or  transverse  process)  directed  forwards  and  continuous 
with  the  iliac  fossa ;  on  either  side  of  the  spinal  canal  is 
the  oblique  or  articular  process,  concave,  and  looking 
backwards  and  inwards  to  receive  the  articular  processes 
of  the  last  lumbar  vertebra  ;  anterior  to  each  is  a  groove, 
which  contributes  with  the  notch  in  the  last  vertebra  to 
form  the'last  of  the  holes  of  conjunction  for  the  passage  of 
the  last  of  the  lumbar  spinal  nerves,  and  behind  the  oblique 
processes  are  the  lamina?,  which  are  sharp,  and  give  attach- 
ment to  the  last  of  the  ligamenta  flava.  The  inferior  ex- 
tremity or  apex  is  directed  downwards,  and  presents  a 
small  oval  convex  surface  to  articulate  with  the  coccyx,  on 
each  side  of  which  is  a  small  notch  for  the  last  sacral 
nerve ;  the  anterior  surface  is  concave  from  above  down- 
wards, flat  from  side  to  side,  marked  by  four  transverse 
lines,  which  indicate  its  original  division  into  five  pieces 
resembling  so  many  vertebrae,  (hence  sometimes  called 
false  vertebra?;)  the  first  of  these -divisions  is  convex,  the 
remaining  are  concave ;  on  either  side  of  the  median  line 
are  the  four  anterior  sacral  holes,  the  two  upper  large,  the 
two  lower  small ;  they  are  all  round  and  smooth,  commu- 
nicate with  the  sacral  canal,  and  transmit  the  anterior  sa- 
cral nerves  ;  grooves  lead  outwards  from  these  holes,  along 
which  the  nerves  run  ;  these  are  analogous  to  the  inter- 
vertebral  holes,  and  the  'intermediate  grooved  bone  to  the 
transverse  processes  in  the  vertebral  column  above  ;  exter- 
nal to  these  is  a  depressed  surface,  which  gives  attachment 
to  the  pyriform  muscle.  The  posterior  or  spinal  surface 
is  convex  and  very  rough,  presenting  in  the  median  line 
four  horizontal  eminences  analogous  to  the  spinous  pro- 
cesses, which  are  often  united  into  one  ridge ;  inferior  to 


DUBLIN    DISSECTOR.  429 

these  the  sacral  canal  ends  in  a  triangular  channel,  which 
is  only  closed  behind  by  ligament  and  bounded  on  each 
side  by  two  tubercles  or  cornua,  beneath  which  is  a 
notch  for  the  last  of  the  sacral  nerves;  these  cornua  are 
sometimes  joined  to  the  base  of  the  coccyx ;  at  either 
side  of  the  median  spine  are  the  four  posterior  holes, 
smaller  and  more  irregularly  formed  than  the  anterior; 
they  transmit  the  posterior  sacral  nerves  ;  external  to  these 
are  a  range  of  tubercles  analogous  to  the  oblique  processes  ; 
the  sides  or  iliac  surfaces  are  uneven,  triangular,  broad 
above,  and  consisting  of  two  portions,  one  superior,  broad 
and  irregular,  covered  with  cartilage  for  articulation  with 
the  ilium ;  the  other  inferior,  thin,  and  attached  to  the  sa- 
cro-sciatic  ligaments.  The  sacrum,  though  very  thick,  is 
yet  light  and  spongy,  and  covered  by  a  thin  lamina  of 
compact  substance  ;  it  is  long  and  narrow  in  the  male, 
broad  and  short  and  more  curved  in  the  female;  in  the 
latter  it  is  about  four  inches  and  a  half  long,  its  breadth 
above  is  nearly  the  same,  but  below  only  half  an  inch;  in 
the  foetus  it  is  nearly  straight,  and  consists  of  five  pieces, 
in  each  of  which  ossification  commences  in  several  points. 

[The  sacrum  is  sometimes  affected  with  spina  bifida ;  it  is  occa- 
sionally contorted  or  twisted,  so  as  to  give  the  spine  a  strong  lateral 
inclination,  and  has  on  one  side  four  and  on  the  other  five  anterior  sa- 
cral foramina,  as  in  a  specimen  belonging  to  Dr.  J.  K.  Rodgers. 
This  bone  may  be  broken,  but  only  by  such  violence  as  usually  to 
cause  death ;  both  this  bone  and  the  vertebrae  are  the  common  seat 
of  caries. 

Muscles.  Seven  pair  are  attached  to  this  bone  ;  five  pair  arise 
from  it,  the  pyriformis  anteriorly,  the  glutens  maximus,  latissimus 
dorsi,  longissirnus  dorsi,  and  sacro-lumbalis  posteriorly  ;  two  pair  are 
inserted  into  it,  multifidus  spinaj  behind,  and  coccygeus  laterally 
and  interiorly. 

Articulations.  The  sacrum  is  articulated  to  four  bones,  the  last 
lumbar  vertebra  above,  the  coccyx  below,  and  the  ossa  innominata 
laterally.] 

The  ossa  coccygis  are  placed  at  the  extremity  of  the  sa- 
crum, and  consist  of  three  or  four  pieces,  which  in  the  old 
are  often  united  into  one  or  two,  but  in  the  young  and  adult 
are  always  distinctly  divisible  into  three  parts,  we  may 
describe  these,  however,  as  forming  a  single  bony  piece 
which  in  the  adult  is  triangular,  and  serves  to  prolong  the 
curve  of  the  sacrum  anteriorly,  the  base  is  above,  with  a 
smooth  oval  surface  adapted  to  the  sacrum,  and  on  either 
side  of  this  posteriorly  is  a  small  horn  or  process  which  is 
also  connected  to  the  sacrum  by  bone  or  ligament ;  beneath 
this  is  a  notch  for  the  last  sacral  nerve ;  the  apex  is  irregu- 
larly tubercular,  and  gives  attachment  to  the  muscles  of 
the  rectum ;  the  anterior  or  pelvic  surface  is  smooth,  sup- 


430  DUBLIN    DISSECTOR. 

ports  the  rectum,  and  is  marked  by  two  or  three  transverse 
lines,  which  indicate  its  original  division  into  distinct  pieces ; 
the  posterior  or  spinal  surface  is  rough  for  the  attachment 
of  muscles ;  it  is  soft  and  spongy,  its  ossification  com- 
mences by  four  or  five  points,  it  becomes  united  to  the  sa- 
crum earlier  in  the  male  than  in  the  female,  and  is  longer 
in  the  former  than  in  the  latter. 

[This  bone  is  analogous  to  the  caudal  vertebras  of  inferior  animals, 
it  sometimes  consists  of  five  pieces.  In  the  adult  it  usually  consists 
of  two  pieces,  th-s  upper  immoveably  fixed  to  the  sacrum,  and  the 
other  moving  upon  the  first,  so  as  to  enlarge  the  antero-posterior 
diameter  of  the  inferior  strait  of  the  pelvis;  this  motion  is  lost  in 
afler  life,  but  is  said  to  exist  donger  in  the  female  than  in  the  male. 
Thjs  bone  may  be  fractured 'by  external  violence,  or  by  internal  pros- 
sure,  as  in  females  who  become  parturient  for  the  first  time  at  a  late 
period  of  life. 

Muscles.  Three  pair  and  a  single  muscle  are  attached  to  this 
bone  ;  the  gluteus  niaximus  and  sphincter  arii  arise  from  it,  and  the 
coccygeus  and  levator  ani  are  inserted  into  it. 

Articulation.     It  is  articulated  to  the  sacrum  only.] 

OSSA  JNNOMINATA. 

As  each  os  innominatum  is  divisible  in  early  life  into  three 
bones,  the  ilium,  ischium,  and  pubis,  it  will  be  found  more 
convenient  to  describe  each  of  these  separately,  in  prefer- 
ence to  considering  the  os  innominatum  as  a  single  bone, 
which,  however,  it  really  becomes  after  puberty. 

The  os  ilium  is  situated  at  the  upper  and  outer  part  of 
the  pelvis,  and  forms  that  projection  commonly  called  the 
hip ;  it  is  broad,  flat  and  triangular,  the  base  above,  and 
semicular,  the  apex  below  forming  the  upper  and  outer 
part  of  the  acetabulum ;  it  may  be  divided  into  the  body, 
ala,  and  processes.  The  body  is  the  inferior  constricted 
portion  which  presents  three  surfaces,  one,  external,  smooth 
and  concave,  forms  the  upper  and  outer  side  of  the  aceta- 
bulum ;  the  second  is  anterior,  small,  triangular,  and  uni- 
ted to  the  pubis;  the  third  is  posterior  and  joined  to  the 
ischium.  The  ala  is  the  broad  fan-like  portion  which  as- 
cends, inclines  outwards  and  a  little  forwards  ;  its  external 
surface  or  dorsumis  irregularly  convex,  rough,  and  marked 
by  two  curved  lines  from  which  the  glutens  rnedius  and 
minimus  arise;  above  and  'behind  the  upper  line  the  bone 
is  rough  for  the  origin  of  the  glutseus  maximus  ;  this  sur- 
face is  also  irregularly  convex,  being  a  little  hollowed 
anteriorly,  it  is  next  much  raised,  it  then  becomes  very 
concave,  and  lastly,  it  is  convex  as  far  as  its  posterior  bor- 
der. The  internal  surface  of  the  ala  is  divided  into  three 
parts;  one  superior  and  anterior,  is  the  iliac  fossa,  which 
gives  origin  to  the  internal  iliac  muscle  ;  the  second  is  pos- 


DUBLIN    DISSECTOR.  431 

terior,  rough,  and  united  to  the  sacrum,  and  the  third  is 
smooth  and  small,  and  is  the  only  portion  of  the  ilium  that 
enters  into  the  side  of  the  true  pelvis;  this  pelvic  portion 
of  the  ilium  is  above  the  sacro-sciatic  notch,  and  is  separ- 
ated from  the  iliac  fossa  by  an  obtuse  ridge  which  is  con- 
tinuous behind  with  the  promontory  of  the  sacrum,  and 
before  with  a  similar  ridge  of  the  pubis  ;  this  line  is  named 
ilio-pectinea,  and  into  the  iliac  portion  of  it  the  tendon  of 
the  psoas  parvus  and  the  iliac  fascia  are  inserted.  The 
processes  are,  first  the  crest,  which  in  the  young  subject  is 
an  epiphysis,  it  forms  the  upper  border  of  the  ala,  it  is 
curved  inwards  before  and  outwards  behind,  and  gives  at- 
tachment to  the  three  layers  of  abdominal  muscles.  Sec- 
ond, anterior  superior  spine,  is  that  prominent  projection  at 
the  upper  and  forepart  of  the  crest  and  ala,  it  gives  attach- 
ment to  the  muscles  and  to  Poupart's  ligament ;  between 
this  and  the  next  process  is  a  notch ;  third,  anterior  inferior 
spine  is  above  the  outer  part  of  the  acetabulum,  it  gives  at- 
tachment to  one  head  of  the  rectus  femoris  muscle ;  the 
notch  between  these  two  spinous  processes  is  filled  by  the 
sartorius  and  iliacus  muscles  ;  internal  to  the  inferior  spine 
is  a  superficial  groove  along  which  the  psoas  and  iliac 
muscles  pass ;  this  groove  is  bounded  internally  by  the 
ilio-pectineal  eminence,  which  is  common  to  the  ilium  and 
pubis  ;  fourth,  the  posterior  superior  spine  is  the  posterior 
termination  of  the  crest,  below  which  is  a  notch  ;  and  fifth, 
the  posterior  inferior  spine ;  these  two  processes  give  attach- 
ment to  ligaments  and  muscles,  beneath  the  inferior  is  the 
commencement  of  the  sacro-sciatic  notch. 

The  ischium  is  placed  at  the  lower,  outer,  and  back  part 
of  the  pelvis,  and  presents  a  body  and  processes ;  the  body 
forms  the  outer,  lower,  and  back  part  of  the  acetabulum, 
more  than  two-fifths  of  which  it  forms,  and  presents  a  pro- 
minent line  or  border ;  beneath  this  is  a  horizontal  groove, 
which  lodges  the  tendon  of  the  obturator  extern  us,  and 
from  this  a  rough  ridge  leads  down  to  the  tuber  of  the  bone, 
and  gives  attachment  to  the  quadratus  femoris  muscle  ;  the 
anterior  part  of  the  body  is  thin  and  sharp,  and  bounds  the 
obturator  or  thyroid  hole  ;  the  posterior  part  joins  the  ilium, 
and  bounds  the  sacro-sciatic  notch.  The  processes  are, 
first  the  spine,  which  arises  from  its  posterior  part  just  be- 
low the  sacro-sciatic  notch;  it  projects  backwards  and  in- 
wards, gives  attachment  to  the  superior  gemellus  and  the 
lesser  sciatic  ligament,  and  bounds  the  great  sciatic  notch 
inferiorly  ;  below  the  spinous  process,  between  it  and  the 
following,  is  the  smooth  pulley  round  which  the  tendon  of 
the  obturator  internus  muscle  turns ;  second,  the  tuberosity 
is  beneath  this  pulley,  and  the  lesser  sacro-sciatic  notch, 


432  DUBLIN    DISSECTOR. 

on  this  process  the  body  rests  in  the  sitting  posture,  it  is 
broad  behind  and  covered  with  cartilage,  it  gives  attach- 
ment to  the  adductor  magnus  and  to  the  hamstring  mus- 
cles ;  on  its  internal  side  is  a  groove  for  the  tendon  of  the 
obturator  externus  ;  third,  the  ramus  ascends  from  the  tuber 
forwards  and  inwards,  and  joins  that  of  the  pubis;  it  is 
thin  and  flat,  one  border  is  thin  and  bounds  the  thyroid 
hole,  the  other  is  thick  and  in  part  bounds  the  low  aperture 
of  the  pelvis ;  to  it  are  attached  the  crus  penis,  and  the 
compressor  penis  muscle. 

The  os  pubis  is  situated  at  the  forepart  of  the  pelvis,  and 
internal  part  of  the  acetabulum  ;  it  may  be  divided  into  its 
body  and  processes  ;  the  body  is  the  most  external,  it  is 
thick,  and  forms  the  internal  and  superior  part  of  the  ace- 
tabulum, above  which  it  joins  the  ilium  in  the  ilio-pectineal 
eminence,  and  below  it  is  united  to  the  body  of  the  ischi- 
um ;  from  this  the  first  process  proceeds,  the  horizontal  ra- 
OTTOS,  forwards  and  inwards,  smooth  and  flat  superiorly,  and 
covered  by  the  pectinosus,  smooth  also  posteriorly  towards 
the  cavity  of  the  pelvis,  and  grooved  beneath  for  the  obtu- 
rator foramen  ;  a  sharp  ridge  separates  its  superior  from 
its  posterior  surface ;  this  ridge  is  the  anterior  part  of  the 
linea  innominata  or  ilio-pectinea,  into  it  the  pectinaeus  mus- 
cle, Gimbernaut's  ligament,  and  the  fascia  lata  are  insert- 
ed ;  at  the  internal  extremity  of  this  ramus  and  of  this  line 
is  the  second  process,  the  tuberosity  or  spine;  this  is  a  pro- 
minent tubercle  into  which  Poupart's  ligament  is  inserted ; 
from  this  spine  the  third  process,  the  crest,  leads  transverse- 
ly inwards  ;  it  is  about  an  inch  in  length  ;  the  rectus  abdo- 
minis  and  pyramidalis  muscles  arise  from  it;  at  its  inter- 
nal end  is  the  fourth  process,  the  symphysis ;  this  descends 
nearly  vertical,  and  is  joined  to  the  opposite  one  by  an  in- 
tervening cartilage  ;  as  the  symphisis  turns  down  from  the 
transverse  crest  there  is  the  angle  of  the  pubis ;  from  the 
lower  part  of  the  symphysis  descends  the  fifth  process,  the 
inferior  or  descending  ramus,  in  an  oblique  direction  back- 
wards and  outwards,  to  meet  the  ramus  of  the  ischium  ; 
this,  with  the  ramus  of  the  opposite  pubis,  forms  the  arch 
af  the  pubis,  its  outer  edge  assists  in  bounding  the  thyroid 
hole. 

The  acetabulum,  or  articular  cavity  for  the  head  of  the 
thigh  bone,  is  formed  by  the  junction  of  the  bodies  of  these 
three  bones  in  different  proportions;  the  ischium  consti- 
tutes a  little  more  than  two-fifths,  the  ilium  somewhat  less 
than  two-fifths,  and  the  pubis  the  remainder  ;  it  is  sur- 
rounded by  a  prominence  which  is  deficient  or  notched 
at  only  one  point,  this  notch  in  the  border  is  opposite  the 
thyroid  hole,  between  the  ischium  and  pubis,  but  chiefly 


DUBLIN    DISSECTOR.  433 

in  the  former  bone,  it  is  situated  at  the  anterior  and  inferior 
part,  it  may  serve  to  admit  of  more  free  adduction  of  the 
limb,  and  it  also  allows  the  articular  vessels  to  enter  the 
joint ;  a  rough  surface,  the  only  part  uncovered  by  carti- 
lage, leads  from  it  to  the  centre  of  the  cavity,  to  this  the 
articular  ligament  and  a  quantity  of  adipose  membrane  are 
connected ;  this  cotyloid  cavity  looks  outwards,  downwards, 
and  forwards,  the  upper  and  outer  portion,  by  which  the 
weight  of  the  head  and  trunk  are  transmitted  to  the 
thigh,  is  the  deepest,  it  is  shallow  at  the  lower  and  internal 
part. 

The  pehis,  which  is  thus  made  up  of  the  ossa  innominatu, 
the  sacrum,  and  ossa  coccygis  may  next  be  examined  as 
one  great  portion  of  the  skeleton,  both  on  its  external  and 
internal  surfaces ;  externally  it  presents  in  front  the  sym- 
physis  and  crests  of  the  pubes ;  the  ilio-pectineal  emi- 
nences, and  beneath  these  the  acetabula  and  the  thyroid 
holes,  more  laterally  is  the  dorsum  of  the  ilium,  marked  by 
its  curved  lines,  posteriorly  the  sacral  spines  occupy  the 
median  line  ;  external  to  these  are  the  sacral  foramina,  be- 
yond these  on  each  side  is  a  rough  surface  for  the  attach- 
ment of  ligaments  and  muscles;  and  lastly,  the  great  sacro- 
sciatic  notches,  which  are  bounded  by  the  sacrum,  ilium, 
and  ischium.  The  superior  circumference  or  base  of  the 
pelvis  which  is  inclined  upwards  and  forwards,  is  formed 
on  each  side  by  the  crest  of  the  ilium,  posteriorly  by  the 
promontory  of  the  sacrum,  on  each  side  of  which  is  a  deep 
notch,  which  is  rilled  by  muscles,  anteriorly  by  the  iliac 
spines,  ilio-pubal  eminences,  the  intervening  grooves,  and 
by  the  ossa  pubis.  ^he  loiver  or  perinatal  circumference  or 
strait  or  apex  of  the  pelvis,  is  directed  downwards  and 
backwards,  and  bounded  by  the  rami  of  the  pubes,  the  ra- 
mi  and  tubera  ischii,  the  sacrum  and  coccyx,  and  in  the 
recent  state  by  the  sacro-sciatic  ligaments  of  each  side,  but 
when  the  latter  have  been  removed  as  in  the  artificial  ske- 
leton, then  this  strait  presents  three  great  notches :  first, 
the  arch  of  the  pubis,  triangular,  and  placed  beneath  the 
symphysis,  the  second  and  third  are  placed  between  the  sa- 
crum and  os  innominatum  of  each  side,  very  large  in  the 
dried  bones,  but  in  the  recent  state  they  are  divided  by  the 
sciatic  ligaments,  each  into  two,  viz.  the  great  or  superior, 
the  lesser  or  inferior  sacro-sciatic  notch  ;  the  former  trans- 
mits the  pyriform  muscle,  the  glutseal,  sciatic,  and  pudic 
vessels  and  nerves,  the  latter  the  tendon  of  the  internal  ob- 
turator muscle,  and  the  pudic  vessels  and  nerves.  The  in- 
ternal surface  of  the  pelvis  is  divided  into  two  by  the  pro- 
minent line  before  mentioned,  the  linea  ilio-pectinea,  which 
leads  from  the  spine  of  the  pubis  to  the  promontory  of  the 
37 


434  DUBLIN    DISSECTOR. 

sacrum,  below  this  line  is  the  true  pelvis,  above  it  is  the 
false  pelvis,  which  is  rather  a  portion  of  the  abdomen ;  this 
line  is  more  distinct  posteriorly  than  anteriorly  ;  this  abdo- 
minal or  upper  strait  of  the  pelvis  is  somewhat  elliptical, 
the  greatest  diameter  being  transverse ;  it  is  measured  by 
four  lines  or  diameters  ;  first,  the  antero-posterior  or  sacro- 
pubic  is  smaller  on  account  of  the  projection  of  the  sa- 
crum ;  second,  the  transverse  or  iliac,  which  crosses  the 
first  at  right 'angles,  and  is  the  greatest;  third  and  fourth, 
the  oblique,  which- leads  from  one  ilio-sacral  articulation  to 
the  opposite  ilio-pubal  eminence,  or  the  cotyloid  wall. 
Above  this  strait  the  great  or  false  pelvis- expands  and  is 
deficient  in  bone  anteriorly,  being  only  closed  by  the  abdo- 
minal muscles.  Beneath  this  strait  is  the  true  pelvis,  which 
is  a  sort  of  curved  canal,  longer  than  the  false  pelvis  and 
wider  about  the  centre  than  at  either  strait,-  with  smooth 
walls,  concave  posteriorly  from  above  downwards,-  concave 
anteriorly  in  the  transverse  direction,  and  on-  either  side 
nearly  plane  :  the  sacrum  and  coccyx  bound  it  posteriorly, 
the  pubes  and  thyroid  foramina  anteriorly,  and  on  either 
side  a  portion  of  the  ilium-  and  ischium,  the  sciatic  notches 
and  ligaments.  The  true  pelvis  is  placed  in  an  oblique  di- 
rection, its  upper  orifice  looking  forwards,  so  that  if  a  line 
be  passed  horizontally  from-  the  upper  border  of  the  sym- 
physrs  pubis  backwards,  it  will  meet  the  middle  or  rather 
the  lower  end  of  the  sacrum4.  The  lower  orifice  looks 
backwards  aud  downwards,  the  axis  of  the  two  orifices 
therefore  is  not  the  same,  that  of  the  superior,  if  produced, 
would  pass  anteriorly  through  the  abdominal  muscles,  be- 
tween the  pubis  and  umbilicus,  and  posteriorly  it  would 
rest  against  the  lower  third  of  the  sacrum  ;  the  axis  of  the 
lower  strait,-  if  produced  from  below  directly  upwards, 
would  touch  the  promontory  of  the  sacrum,  these  lines 
therefore  wilt  decussate  near  the  centre  of  the  pelvis,  and 
form  an  obtuse  aiTgle  forwards.  The  axis  of  the  false  pel- 
vis is  nearly  vertical1,  while  that  of  the  true  cavity  is  ob- 
lique from  above  and  from  before  downwards  and  back- 
wards. The  female  pelvis  differs  from  that  of  the  male  in 
several  circumstances,  it  is  wider  and  larger,  but  not  so 
deep,  the  alee  of  the  ilium  are  more  expanded,  the  promi- 
nence of  the  sacrum  is  less,  the  upper  strait  is  rounder  and 
wider,  the  sacrum  is  broad  and  more  concave,  the  pubic 
arch  more  round  and  open,  the  symphisis  pubis  is  not  so 
deep,  the  sciatic  tuberosities  are  directed  more  outwards, 
and  the  acetabula  are  more  distant  from  each  other ;  the 
male  pelvis  is  deeper,  narrower,  and  stronger.  The  dimen- 
sions of  the  male  and  female  pelvis  are  given  by  Meckel, 
as  follows,  torn.  i.  p.  473. 


DUBLIN    DISSECTOR.  435 


In  the  Male. 
Inches.  Lines. 

The  transverse  diameter  of  the  great  pelvis  be-  1 
tween  the  anterior  superior  spinous  processes  >      7  8 

of  the  ilia,        -  -     ) 

Distance  between  the  crisis  of  the  ilia,    -  8  3 

Transverse  diameter  of  the  superior  strait,  4  6 

Oblique  do.       of  do.  -  -      4  5 

Antero-postefior    do.    of          do.  4  0 

Transverse  diameter  of  the  cavity,  -  -      4  0 


In  the  Female. 
Inches.  Lines. 


9  4 

5  0 

4  5 

4  4 

4  8 


Oblique  do.        of        do.  -  5  0  5 

Aiitero-posterior  ,  do.    of    do.  -  -      5  0  4 

Transverse  diameter  of  the  lower  strait  or  outlet       3045 
Antero-posterior    do.      of  do.        -  -      3  3  44 

The  latter  may  be  increased  to  5  inches,  from  the  mobility  of  the  coccyx. 

The  ossa  innominata  are  composed  of  two  thin  but  com- 
pact laminae  with  an  intervening  diploe,  the  latter  is  nearly 
wanting  in  the  iliac  fossa,  where  the  bone  is  transparent, 
as  well  as  in  the  cotyioid  cavity.  In  the  foetus  each  os  in- 
nominatum  is  developed  from  three  points  of  ossification, 
one  in  the  iliac  fossa,  one  in  the  sciatic  tubercle,  and  ono 
near  the  spine  of  the  pubis ;  these  three  soon  unite  in  the 
cotyioid  cavity.  Some  years  after  birth  the  iliac  crest  is 
developed  as  a  distinct  epiphysis,  the  sciatic  tubercle  and 
anterior  inferior  spine  of  the  ilium  are  also  covered  by  dis- 
tinct plates  of  bone,  and  in  some  the  angle  of  the  pubis; 
in  some  females  also,  a  plate  of  bone  or  epiphysis  consti- 
tutes the  spine  of  the  pubis,  and  occasionally  grows  so 
large  and  remains  so  moveable,  as  to  resemble  the  rudi- 
ments of  a  marsupial  bone.  Jn  .the  fretus,  the  pelvis  is 
very  small  and  deep,  and  narrow  transversely  ;  the  true 
and  false  are  nearly  in  the  same  perpendicular  line,  the 
acetabula  are  nearer  the  middle  line  and  look  more  out* 
wards,  they  are  not  beneath  the  pelvis  as  in  the  adult* 
hence  the  thigh  bones  in  the  infant  cannot  support  or 
balance  the  weight  of  the  trunk. 

[The  os  innominatum  is  sometimes  fractured  by  great  external 
violence,  and  severe  inflammation  of  the  soft  parts  will  ensue  :  some- 
times the  bone  is  perforated  at  the  bottom  of  the  iliac  fossa  which  is 
by  some  supposed  to  be  natural,  by  others  to  result  from  absorption 
of  the  bone.  The  articulation  at  the  symp!iy.<is  pubis  is  relaxed  in 
some  inferior  animals  during  parturition,  but  no  such  relaxation  takes 
place  in  the  human  female  ;  or  if  it  does  occur,  it  is  morbid,  and  fol- 
lowed by  serious  consequences. 

Muscles.  Thirty-two  pair  of  muscles  are  attached  to  this  bone; 
thirty  pair  arise  from  it ;  the  latissimus  dorsi,  internal  oblique,  trans, 
versalis  abdominis,  and  quadratus  femoris  from  the  crest  of  the 
ilium ;  the  tensor  vagina  femoris  and  sartorius  from  its  anterior  su- 
perior spine;  the  rectus  femoris  from  its  anterior  inferior  spine  ;  the 
pectineus,  adductor  longus,  adductor  brevis  and  gracilis,  from  the 
upper  and  fore  part  of  the  pubis  ;  the  pyramidalis,  and  reclus  abdo. 
minis  from  its  crest ;  erector  penis  and  adductor  magnus  from  the 
rami  of  the  pubis  and  ischium ;  the  biceps  flexor  cruris,  semitendino- 


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DUBLIN    DISSECTOR.  437 

spine  or  process,  which  supports  the  nasal  bones  before,  mid 
tnO  ethmoid  bone  behind,  on  each  side;  of  this  is  a  groove 
Which  forms  part  Of  tho  superior  nasal  fossa1.  On  i -ithcr 
side  of  the  median  line  of  the  frontal  hour,  and  proceed- 
ing from  above  downwards,  we  observe,  first,  a  smooth 
surface,  covered  by  the  occipito-frontalis  muscle  ;  second, 
the  frontal  eminence,  which  is  particularly  prominent  in 
the  young;  beneath  this  is  a  slight  depression,  bounded 
below  by  the  superciliary  arch,  towards  the  inner  third  of 
which  is  the  supra-orbital  hole,  or  notch,  which  is  com- 
pleted into  a  hole  by  a  ligament,  and  which  transmits  tho 
supra-orbital  nerve  and  vessels;  from  this  notch  a  small 
foramen  leads  obliquely  into  tin;  diploe  of  tin:  bone;  im- 
mediately above  the  internal  third  of  this  arch  is  the  pro- 
minence of  the  frontal  sinus,  and  below  it  is  the  edge  of 
the  orbit,  at  each  extremity  of  which  are  the  angular  pro- 
cesses; the  external  is  prominent  and  joins  the  malar  bone, 
the  internal  is  thin  and  broad,  covers  some  cells,  and  joins 
the  unguis  ;  above  and  outside  the  external  is  the  temporal 
ridge  or  process,  which  is  prominent  below  and  leads  up- 
wards and  backwards  to  join  a  similar  ridge,  on  the  parietal 
bone,  this  separates  the  forehead  from  the  temple,  and 

gives  attachment  to  the  temporal  muscle  and  fascia.  On 
the  cerebral  or  internal  surface  of  this  portion  of  the 
frontal  bone,  we  observe  in  the  median  line  a  groove;  for 
the  longitudinal  sinus  ;  interiorly  tin-  edges  of  tins  groove 
unite  into  a  ridge  to  which  the  falx  adheres,  and  which  ex- 
tends down  to  a  small  hole,  the  foramen  ca'cum,  which  is 
between  this  bone  and  the  ethmoid  ;  on  either  side  of  this 
median  lino  are  numerous  irregularities,  corresponding  to 
the  convolutions  of  the  brain,  in  general,  but,  not  uniformly, 
for  occasionally  a  prominent  part  of  the  bone  is  opposed 
to  an  eminence  of  the  brain  ;  these  are  named  the  marn- 
millary  eminences,  and  the  digital  impressions,  in  some  of 
the  latter  the  bone  is  often  very  thin.  The  circumference 
of  the  os  frontis  is  thick,  rough,  and  serrated  to  join  tho 
parietal  bones;  the  tables  are  cut  unequally,  the  internal 
being  deficient  above,  the  external  below,  so  that  it  rest;* 
on  or  binds  down  the  two  parietal  bones  abov,  and  sup- 
ports or  is  overlapped  by  these  below;  below  the  temporal 
process  it  is  bevelled  otf  thin  arid  rough,  and  is  inserted 
under  and  between  the  laminae  of  the  ala  of  the  sphenoid 
bone.  The  inferior  portion  of  the  frontal  bone  presents  the 
deep  ethmoidal  notch  in  the  centre,  in  front  of  which  is  tho 
nasal  spine  and  the  orifices  of  the  frontal  sinuses,  its  edges 
are  cellular  to  unite  to  and  communicate  with  the  colls  of  the 
ethmoid  bone  ;  along  its  margins  are  two  foramina,  the 
anterior  and  posterior  orbital,  they  arc  common  to  this 
37* 


438  DUBLIN    DISSECTOR. 

and  to  the  ethmoid  bone,  the  anterior  transmits  the  nasal 
twig  of  the  ophthalmic  nerve  and  anterior  ethmoidal  ar- 
tery, the  posterior,  the  posterior  ethmoidal  artery ;  on 
cither  side  are  the  orbital  processes,  smooth,  concave,  and 
triangular,  the  apex  behind  presenting  near  the  external 
angular  process  a  deep  pit  for  the  lachrymal  gland,  and 
near  the  internal  a  slight  depression  for  the  cartilaginous 
pulley  of  the  superior  oblique  muscle  of  the  eye,  instead 
of  a  depression  there  is  sometimes  a  small  spine  ;  the  cere- 
bral surface  of  these  processes  is  convex,  but  very  uneven, 
marked  by  the  brain  and  vessels ;  their  posterior  margins 
are  thin,  and  cut  obliquely  to  support  the  lesser  wings  of 
the  sphenoid  bone.  The  processes  of  this  bone,  enume- 
rated by  anatomists,  are  eleven,  viz.,  two  orbital,  four  an- 
gular, two  superciliary,  two  temporal,  and  one  nasal ;  the 
foramina  are  nine,  viz',  one,  the  foramen  coecum ;  two  and 
three,  the  frontal  sinuses,  between  the  nasal  and  internal 
angular  processes ;  four  and  five,  the  supra-orbital ;  six 
and  seven,  the  anterior;  and  eight  and  nine  the  posterior 
orbital ;  these  last,  as  well  as  the  foramen  coacum,  are 
often  common  to  this  and  the  ethmoid  bone.  The  os  frontis 
is  joined  to  four  bones  of  the  cranium,  viz.,  the  two  parie- 
tal, the  sphenoid  and  ethmoid,  and  to  eight  bones  of  the 
face,  viz.,  the  nasal,  superior  maxillary,  lachrymal,  and 
malar.  The  structure  is  thick  towards  the  nasal  protu- 
berance and  superciliary  ridges,  but  very  thin  in  the  or- 
bital plates ;  it  is  composed  of  two  compact  laminae  and 
an  intervening  diploe,  by  the  absorption  of  the  latter  and 
the  greater  separation  of  the  plates,  the  cavities  called  the 
frontal  sinuses  are  formed ;  these  do  not  exist  in  childhood, 
and  in  the  adult  their  extent  is  very  variable ;  they  gene- 
rally extend  from  the  ethmoid  notch  upwards  and  outwards 
for  one-third  of  the  superciliary  arch,  sometimes  much 
further  ;  they  are  generally  separated  by  a  septum  ;  their 
use  is  not  fully  ascertained.  This  bone  is  developed  from 
two  points  of  ossification,  one  in  each  frontal  prominence  ; 
from  this,  ossification  extends  in  rays  which  unite  in  the 
middle  line,  but  occasionally  a  suture  remains  between 
them ;  this  has  been  said,  but  without  sufficient  foundation, 
to  be  more  frequent  in  women  than  in  men. 

[The  os  frontis  is  sometimes  developed  by  three  pieces,  which  arr 
distinct  at  the  time  of  birth,  the  third  piece  being  situated  upon  the. 
median  line,  ovoid  in  form,  and  separating  the  two  lateral  parts ;  of 
this  there  is  a  specimen  in  the  Museum.  The  frontal  suture  is  rather 
rare,  I  have  seen  six  or  eight  specimens  of  it.  The  frontal  sinuses* 
sometimes  spread  over  a  large  portion  of  the  orbit,  and  one  case  is 
recorded  in  which  they  extended  upwards  and  backwards,  beyond 
the  coronal  or  temporo-frontal  suture  ;  they  are  lined  with  mucous 


DUBLIN    DISSECTOR.  439 

membrane,  which  is  sometimes  the  seat  of  inflammation  ;  they  com- 
municate  with  the  anterior  ethmoiclal  cells. 

Muscles.  Four  pair  arc  attached  to  this  bone ;  three  pair  arise 
from  it,  the  temporal  from  its  temporal  ridge  and  surface;  the  orbi- 
cularis  palpebrarum  and  corrugalor  supercilii  from  its  internal  angu- 
lar processes ;  and  the  occipito  frontalis  is  inserted  into  the  integu- 
ments over  its  front  and  lower  part.] 

The  parietal  bones  are  symmetrical,  and  form  the  upper 
and  lateral  parts  of  the  cranium  ;  each  is  nearly  square, 
convex  and  smooth  externally,  about  the  centre  is  the  pro- 
tuberance, which  is  better  marked  in  children,  below  this 
is  the  curved  temporal  ridge  continuous  with  the  pro- 
cess of  that  name  on  the  os  frontis,  to  this  the  temporal 
aponeurosis  adheres ;  below  this  it  is  rough  for  the  attach- 
ment of  the  temporal  muscle;  of  the  four  edges,  the  upper 
or  perietal  is  the  longest,  it  is  serrated,  and  with  the  oppo- 
site bone  forms  the  sagittal  suture  ;  the  anterior  or  frontal 
edge  is  also  serrated  to  join  the  os  frontis  in  the  coronal 
suture;  the  posterior  or  occipital  edge  is  very  irregular, 
and  joins  the  occipital  bone  in  the  lambdoid  suture  :  in  this 
suture  small  bones  called  ossa  Wormii  or  triquetra  are 
often  found  ;  the  inferior  or  temporal  edge  is  the  shortest, 
it  is  concave,  and  joins  the  temporal  bone  by  the  squamous 
suture ;  of  its  four  angles  the  anterior  superior  is  nearly 
right,  in  the  child  this  is  deficient  and  the  fontanelle  exists ; 
the  superior  posterior  angle  is  somewhat  rounded;  near 
this  in  general  is  a  foramen  [parietal]  which  transmits  small 
vessels  from  the  pericranium  to  the  dura  mater,  the  inferior 
anterior  is  long  and  curved,  and  joins  the  sphenoid  bone, 
the  inferior  posterior  is  very  irregular  and  joins  the  mastoid 
portion  of  the  temporal  bone  :  the  cerebral  surface  is  mark- 
ed by  the  convolutions  of  the  brain,  and  by  the  branches 
of  the  middle  artery  of  the  dura  mater;  this  vessel  is  in  a 
groove,  sometimes  in  a  perfect  canal  or  tube  in  the  anterior 
inferior  angle,  and  from  this  the  branches  pass  upwards 
and  backwards,  a  large  one  ascends  a  little  posterior  to  the 
coronal  edge ;  along  the  parietal  border  is  half  a  groove, 
which  with  that  in  the  opposite  bone,  lodges  the  longitudi- 
nal sinus;  and  near  this  in  the  adult  skull  are  irregular 
depressions  for  the  glandular  Pacchioni  or  the  granulations 
of  the  dura  mater  ;  the  posterior  inferior  angle  is  grooved 
and  lodges  part  of  the  lateral  sinus :  the  structure  of  the 
perietal  bone  is  similar  to  that  of  the  frontal ;  it  is  devel- 
oped from  one  point  of  ossification,  which  is  in  the  parietal 
prominence;  it  is  joined  to  five  bones,  viz.  the  frontal, 
sphenoid,  temporal,  occipital,  and  to  its  fellow. 

Muscles,    One  muscle  only  is  attached  to  this  bone,  the  temporal, 


440  DUBLIN    DISSECTOR. 

which  arises  from  it ;  the  occipito-frontalis  slides  over  it  to  some  ex- 
tent.] 

The  occipital  bone  is  curved  and  of  a  rhomboidal  figure, 
placed  at  the  posterior  and  inferior  part  of  the  cranium ; 
it  presents  two  surfaces,  the  external  or  posterior,  or  basi- 
lar,  is  convex,  smooth  above,  presents  near  the  centre  the 
great  protuberance  to  which  the  cervical  ligament  is  connect- 
ed ;  from  each  side  ,of  this  leads  the  superior  transverse 
ridge,  to  which  the  occipito-frontales,  trapezii,  and  complex i 
muscles  are  attached  ;  midway  between  this  and  the  fora- 
men magnum,  is  the  inferior  transverse  ridge,  to  which  the 
splenii,  recti.majores  and  obliqui  superiores  are  attached  ; 
from  the  tuberosity  a  spine  leads  down  vertically  in  the 
median  line  as  far  as  the  foramen  magnum ;  this  latter  is 
of  an  oval  figure,  and  transmits  the  medulla  spinalis,  the 
vertebral  vessels,  and  the  sub-occipital  nerves-;  it  is  larger 
internally  than  externally,  in  .front  of  this  is  the  -basilar 
process,  which  is  very  thick  and  strong,  it  passes  forwards 
and  a  little  upwards  .into  the  base  of  the  skull  to  join  the 
sphenoid  bone.;  its  sides  are  rough  and  contiguous  to  the 
petrous  bones;  it , is  also  rough  inferiorly,  for  the  attach- 
ment of  muscles  and  the  mucous  membrane  of  the  pharynx. 
Near  the  forepart  of  the  foramen  are  the  condyles,  smooth 
and  oblong,  covered  with  cartilage,  looking  downwards, 
outwards,  and  backwards,  and  converging  anteriorly  ;  their 
anterior  and  inner  edges  are  the  deepest,  their  long  axis  is 
from  before  backwards,  in  which  direction,  as  also  from  side 
to  side  they  are  convex,  they  are  uneven  internally  near 
their  centre,  for  the  insertion  of  the  lateral  ligaments  from 
the  odontoid  process ;  they  are  articulated  to  the  atlas ; 
behind  these  is  a  fossa  in  which  there  is  generally  a  small 
foramen  through  which  a  vein  and  small  artery  pass,  and 
before  them  is  another  fossa  in  which  there  is  always  a 
foramen  for  the  ninth  pair  of  nerves,  [the  posterior  and 
anterior  condylaid  foramina.']  External  to  each  condyle  is 
the  jugular  eminence,  semilunar,  bounding  posteriorly  the 
foramen  lacerum  posterius  in  the  base  of  the  cranium  and 
giving  attachment  to  the  rectus  lateralis  muscle.  The  up- 
per angle  is  acute ;. -the  edges  very  irregular  as  also  along 
the  sides ;  ossa  triquetra  are  often  entangled  in  the  notches. 
The  internal  or  .cerebral  surface  is  concave,  and  marked 
by  two  lines  which  cross  about  the  centre,  or  opposite  the 
tuberosity,  these  bound  four  fossce,  the  two  superior  receive 
the  posterior  lobes  of  the  cerebrum,  and  are  marked  by  their 
convolutions,  the  inferior  are  smooth,  and  lodge  the  hemis- 
pheres of  the  cerebellum,  to  the  vertical  ridge  is  attached 
the  falx  cerebri  above  and  falx  cerebelli  below ;  the  lower 
extremity  of  the  latter  is  bifurcated,  the  upper  half  is 
grooved  for  the  longitudinal  sinus;  to  the  transverse  ridge 


DUBLIN    DISSECTOR.  441 

the  tentorium  is  attached,  it  is  grooved  for  the  lateral  sinus ; 
the  basilar  process  is  concave  from  side  to  side,  to  support 
the  pons  Varolii  and  the  basilar  artery  ;  on  either  margin 
of  it  is  a  slight  groove  for  the  inferior  petrosal  sinus :  on 
each  side  of  the  foramen  magnum  above  the  jugular  pro- 
cesses is  a  groove  for  the  lower  extremity  of  the  lateral 
sinus.  This  bone  is  joined  to  six  bones,  viz.  the  two  parie- 
tal, two  temporal,  the  sphenoid,  and  the  atlas.  Its  process- 
es are  six,  namely,  two  condyles,  two  jugular,  the  basilar, 
and  the  tuberosity.  Its  foramina  are  five  proper  and  two 
common ;  the  proper  are,  the  magnum,  the  two  anterior 
and  two  posterior  condyloid  ;  the  common  are,  the  forami- 
na lacera  postica  basis  cranii,  these  foramina  are  comple- 
ted by  the  petrous  bone,  each  is  imperfectly  divided  into 
two,  a  small  anterior  portion  which  transmits  the  eighth 
pair  of  nerves,  and  a  large  posterior  one,  or  thimble-like 
fossa,  which  lodges  the  lateral  sinus  as  it  ends  in  the  jugular 
vein.  This  is  a  very  hard  bone,  although  thin  throughout 
except  at  the  ridges  and  processes ;  it  is  developed  from 
four  points,  one  for  the  basilar  process,  one  for  each  con- 
dyle,  and  one  for  the  upper  and  back  part. 

[The  whole  of  this  bone  above  the  superior  transverse  ridge  is 
sometimes  composed  of  three  or  four  large  ossa  triquetra ;  this  bone 
and  the  sphenoid  become  inseperably  united  in  the  adult  subject, 
which  is  also  true  of  some  inferior  animals,  hence  the  two  are  de- 
scribed as  a  single  bone  by  some  anatomists  under  the  name  of  oa 
basilare  ;  the  groove  for  the  right  lateral  sinus  is  usually  larger  and 
deeper  than  that  for  the  left,  and  sometimes  it  is  continued  almost 
vertically  from  the  longitudinal  sinus  towards  the  foramen  magnum, 
near  which  it  diverges  to  reach  the  foramen  lacerum  posterius. 

Muscles-  Thirteen  pair  are  attached  to  this  bone;  two  pair  arise 
from  it,  the  occipito-frontalis  and  trapezius  from  the  superior  trans- 
verse ridge  ;  eleven  pair  are  inserted  into  it;  the  sterno-mastoid  into 
the  superior  transverse  ridge,  the  splenius  capitis  externally  and  the 
complexus  internally  into  the  space  between  the  two  transverse 
ridges  ;  recti  capitis  postici  major  and  minor,  and  obliquus  capitis  su- 
perior, between  the  inferior  transverse  ridge  and  the  foramen  mag- 
num ;  the  rectus  capitis  lateralis  into  the  jugular  process;  the  recti 
capitis  antici  major  and  minor,  and  superior  and  middle  constrictor 
muscles  of  the  pharynx  into  the  basilar  process.] 

The  temporal  bones  are  situated  at  the  lateral,  middle,  and 
inferior  parts  of  the  skull,  of  a  very  irregular  shape,  thin 
above  and  before,  and  thick  behind  and  below  ;  each  may 
be  divided  into  three  portions,  the  squamous,  the  mastoid, 
and  the  petrous.  The  pars  squamosa  is  the  superior  divi- 
sion, it  is  flat,  thin,  and  scaly,  forms  part  of  the  temporal 
fossa,  is  bounded  above  by  a  semicircular  edge,  and  below 
by  the  zygomalic  process,  which  is  horizontal  and  arises  by 
two  roots,  one  anterior  covered  by  cartilage,  narrow  exter- 


442  DUBLIN    DISSECTOR. 

nally,  broad  internally,  runs  transversely  in  front  of  the 
glenoid  cavity,  the  other  passes  horizontally  backwards, 
and  bifurcates,  one  portion  turns  in  to  the  glenoid  fissure, 
the  other  is  gradually  lost  above  the  mastoid  process  ;  where 
these  two  roots  of  the  zygoma,  the  one  transverse,  the  other 
horizontal,  unite,  there  is  a  small  tubercle  to  which  the  ex- 
ternal lateral  ligament  of  the  lower  jaw  is  attached  ;  the 
zygoma  thence  bends  forwards  and  downwards,  slightly 
curved,  convex  outwards,  and  ends  in  a  serrated  edge  which 
joins  and  rests  on  the  malar  bone  ;  between  the  root  of  this 
process  and  the  squamous  plate  there  is  a  smooth  trochlea, 
over  which  the  posterior  part  of  the  temporal  muscle  moves ; 
behind  the  transverse  root  of  this  process  is  the  articular  or 
glenoid  cavity,  which  is  crossed  by  the  Glasserian  fissure ; 
this  leads  inwards  and  forwards,  into  it  the  capsular  Liga- 
ment is  inserted,  and  near  its  centre  is  a  small  hole  through 
which  the  corda  tympani  nerve  and  the  laxator  tympani 
muscle  pass;  to  this  fissure  also,  the  processus  gracilis  of 
the  malleus  is  attached  ;  the  anterior  part  only  of  this  ca- 
vity enters  into  the  maxillary  articulation,  the  posterior  is 
filled  by  the  parotid  gland,  and  is  bounded  by  the  auditory 
process ;  this  leads  inwards  and  forwards  behind  the  glenoid 
cavity  from  the  external  auditory  hole,  which  is  between  the 
two  divisions  of  the  outer  root  of  the  zygoma;  this  process 
or  meatus  is  a  twisted  plate  of  bone,  united  above  to  the 
squamous  plate,  but  presenting  below  a  rugged  edge  to 
which  the  cartilage  of  the  ear  is  attached ;  the  meatus  takes 
a  direction  forwards,  inwards,  and  a  little  downwards,  it  is 
narrower  about  the  centre  than  at  the  extremities,  it  leads 
to  the  membrana  tympani.  The  squamous  plate  internally 
is  marked  by  vessels  and  by  the  convolutions  of  the  brain, 
like  the  other  bones  of  the  cranium;  its  upper  edge  is 
bevelled  off  and  is  very  rough  to  overlap  the  parietal  bone. 
The  mamillary  or  mastoid  is  the  posterior  inferior  portion,  it 
is  joined  to  the  parietal  bone  above,  and  to  the  occipital  be- 
hind, by  a  very  deeply  serrated  edge,  inferiorly  it  is  pro- 
longed into  a  rough  nipple-like  process,  the  mastoid,  internal 
to  which  is  a  groove  for  the  occipital  artery,  and  another 
partly  behind  it  for  the  digastric  muscle,  above  and  behind 
it,  is  a  hole  [the  mastoid  foramen]  through  which  a  vein 
and  small  artery  pass;  this  process  is  hollowed  out  into 
cells  which  communicate  with  the  tympanum,  it  gives  at- 
tachment to  the  sterno-mastoid  muscle ;  the  cerebral  sur- 
face is  deeply  grooved  for  the  lateral  sinus.  The  petrous 
portion  passes  from  the  junction  of  the  mastoid  and  squamous 
forwards  and  inwards  into  the  base  of  the  skull,  it  is  of  a 
triangular  form,  the  base  behind  and  very  irregular,  with  a 
deep  notch  which  assists  the  occipital  bone  in  forming  tha 


DUBLIN    DISSECTOR.  443 

foramen  lacerum  posterius ;  the  apex  is  anterior^ contiguous 
to  the  body  of  the  sphenoid  bone,  and  completing  with  it 
the  foramen  lacerum  anterius,  which  in  the  recent  state  is 
filled  up  with  cartilage  ;  this  bone  is  peculiarly  hard  and 
rugged  ;  on  its  inferior  surface  we  remark  in  front  of  the 
foramen  lacerum  posterius  a  minute  hole  which  leads  to 
the  cochlea,  and  is  named  the  aqueduct  of  the  cochlea  ; 
more  anteriorly  and  externally  is  the  styloid  process  which 
descends  obliquely  inwards  and  forwards,  and  gives  attach- 
ment to  three  muscles ;  it  is  surrounded  at  its  base  or  root 
by  a  plate  of  bone  most  prominent  anteriorly  and  exter- 
nally, this  is  named  the  vaginal  process;  it  separates  the 
glenoid  fossa  from  the  carotid  foramen  ;  behind  and  out- 
side the  styloid  process,  between  it  and  the  mastoid,  is  the 
stylo-mastoid  hole  or  the  lower  end  of  the  aqueduct  of  Fallo- 

Eius,  this  transmits  the  portio  dura  or  the  facial  nerve;  irt 
*ont  of  the  styloid  process,  and  a  little  internal  to  it-,  is  the 
carotid  hole  which  leads  into  a  canal  that  winds  forwards,- 
upwards,  and  inwards,  and-  which  opens  within  the  cranium 
above  the  foramen  lacerunr  anterius  by  the  side  of  the  body 
of  the  sphenoid  bone,  it  transmits  the  carotid  artery  and 
branches  of  the  sympathetic  nerve  :  in  front  of  the  carotid 
hole  is  a  flat  rough  surface  to  which  the  muscles  of  the 
palate  are  attached.  The  apex  of  the  petrous  bone  is  very 
irregular,  it  lies  in  the  foramen  lacerum  anterius,  the  inter- 
nal opening  of  the  carotid  canal  is  in  it ;  into  the  angle  be- 
tween the  petrous  and  squamous  portions  the  spinous  part 
of  the  sphenoid  bone  is  wedged  ;  in  this  angle  there  are  two 
holes  separated  by  a  thin  lamina  of  bone,  the  upper  trans- 
mits the  teasor  tympani  muscle,  the  lower  is  the  extremity 
of  the  bony  part  of  the  Eustachian  tube.  The  superior  or 
cerebral  surface  presents  a  prismatic  form,  a  sharp  angular 
ridge  to  which  the  tentorium  cerebelli  is  attached,  separates 
its  two  surfaces,  one  looks  forwards  and  upwards,  the  other 
backwards  and  inwards ;  on  the  superior  we  observe  ante- 
riorly a  slight  depression  which  corresponds  to  the  Casse- 
rian  ganglion  of  the  fifth  pair  of  nerves;  leading  from  this 
is  a  delicate  groove  which'  conducts  to  a  small  opening,  the 
hiatus  Fallopii.  through  which  the  superior  branch  of  the 
Vidian  nerve  passes  in  order  to  enter  the  aqueduct  of  Fallo- 
pius  ;  the  remainder  of  this  surface  is  marked  by  the  con- 
volutions of  the  brain,  and  by  the  eminence  of  the  superior 
semicircular  canal ;  on  the  posterior  surface  is  the  mealus 
auditorius  interims,  through  which  pass  the  two  portions  of 
the  seventh  pair  of  nerves,  it  is  directed  forwards,  and  out- 
wards, is  lined  by  dura  mater,  and  is  terminated  abruptly 
by  a  vertical  bony  process,  beneath  which  is  a  sort  of  crib- 
riform plate,  through  this  the  auditory  nerves  pass,  and 


444  DUBLIN    DISSECTOR. 

above  this  the  portio  dura  enters  the  aqueduct  of  Fallopius ; 
the  latter  is  a  very  long  canal,  which  leads  outwards  and 
downwards  behind  the  tympanum  ;  the  hiatus  Fallopii  and 
some  canals  from  the  tympanum  open  into  it,  it  ends  in  the 
stylo-mastoid  foramen ;  behind  the  meatus  is  a  small  de- 
pression lined  by  the  dura  mater,  and  posterior  to  this  is  a 
narrow  short  slit  in  which  the  canal  of  the  vestibule  ends, 
from  this  slit  a  groove  descends  to  the  jugular  opening. 
The  petrous  bone  contains  within  it  the  complicated  appa- 
ratus of  the  organ  of  hearing  which  has  been  already  de- 
scribed, (page  89.)  The  temporal  bone  is  connected  to  five 
bones,  the  parietal,  malar,  sphenoid,  occipital,  and  inferior 
maxillary,  and  in  some  to  the  os  hyoides.  In  the  foetus  it 
consists  of  two  portions,  the  squamous  and  petrous,  the  lat- 
ter is  large  and  well  developed,  and  the  ossicula  auditus 
which  it  contains  are  perfect,  and  nearly  as  large  as  in  the 
adult,  the  mastoid  portion  is  not  formed,  the  styloid  process 
is  cartilaginous,,  and  is  distinct  from  the  rest  of  the  bone, 
the  external  auditory  meatus  is  wanting,  a  bony  ring  sup- 
plies its  place  and  encircles  the  tympanum.  The  processes 
enumerated  are  five,  viz.  the  mastoid,  auditory,  zygomatic, 
styloid,  and  vaginal ;  the  holes  are  ten  proper  arid  two  com- 
mon ;  the  proper  are,  the  external  auditory,  glenoidal,  stylo- 
mastoid,  aqueductus  cochlea?,  carotid,  Eustachian,  hiatus 
Fallopii,  internal  auditory,  and  aqueductus  vestibuli ;  the 
common  are  the  foramen  lacerum  anticum,  and  posticum 
or  jugular. 

[The  mastoid  foramen  may  be  wholly  in  the  mastoid  portion,  or 
wholly  in  the  os  occipitis,  or  common  to  the  two. 

Muscles.  Fourteen  muscles  are  attached  to  the  bone  of  each  side ; 
eleven  arise  from  it ;  the  temporal  from  the  squamous  plate  ;  the 
inasseter  from  the  zygoma ;  the  occipito-frontalis,  digastricus  and  re- 
trahens  aurem  from  the  mastoid  process ;  the  stylo-hyoideus,  stylo- 
glossus,  and  stylo-pharyngeus  from  the  styloid  process ;  the  levator 
palati,  tensor  tympani  and  stapedius  from  the  petrous  portion  :  three 
are  inserted  into  it  the  splenius  capitis^  sterno-mastoid  and  trachelo- 
mastoid  into  the  mastoid  portion.] 

The  ethmoid  bone  is  situated  in  the  notch  between  the  or- 
bital plates  of  the  frontal  bone,  and  forms  the  roof  of  the 
nostrils;  it  is  so  named  from  its  cribriform  or  sieve-like 
appearance,  it  is  of  a  cuboid  figure,  and  composed  of  many- 
thin,  brittle,  semi-transparent  laminae,  placed  in  every  di- 
rection so  as  to  form  cells,  these  enlarge  the  surface  of  the 
nose  without  increasing  the  size  or  weight,  for  this  bone  is 
remarkably  light.  It  consists  of  a  middle  perpendicular 
lamina  and  two  symmetrical  portions,  its  superior  or  cere- 
bral surface  is  broad  and  covered  by  the  dura  mater,  in  its 
posterior  edge  is  a  notch  which  receives  a  process  of  the 


DUBLIN    DISSECTOR.  445 

sphenoid  bone,  along  the  middle  line  is  a  hard  ridge,  which 
anteriorly  rises  into  a  remarkable  process,  the  crista  galli^ 
to  which  the  beginning  of  the  falx  is  attached,  this  process 
ends  before  in  two  short  wings  which  join  the  os  frontis, 
and  which  often  assist  in  bounding  the  foramen  ccecum ; 
on  either  side  of  this  process  is  a  channel  deeper  before 
than  behind,  these  lodge  the  olfactory  nerves ;  anterior  to 
each  of  these,  and  nearer  to  the  process,  is  a  small  slit 
[the  foramen  ovale]  which  transmits  the  nasal  branch  of 
the  ophthalmic  nerve ;  this  entire  surface  is  perforated  by 
numerous  holes,  about  ten  or  twelve  of  these  are  large,  and 
are  placed  over  the  lateral  parts  of  the  bone,  the  remainder 
are  very  small  and  are  on  either  side  of  the  median  line, 
they  each  lead  into  a  small  vertical  canal  lined  by  dura 
mater ;  from  the  inferior  surface  of  this  plate,  there  de- 
scends the  nasal  lamella  in  the  middle  and  a  large  spongy 
cellular  mass  on  either  side  ;  the  nasal  lamella  is  in  the  me- 
dian line,  it  is  thick  above  and  behind  where  it  joins  the 
sphenoid,  thin  below  where  it  joins  the  vomer  and  nasal 
cartilage,  and  very  thick  before  where  it  unites  to  the  nasal 
process  of  the  os  frontis  and  to  the  nasal  bones,  its  sides 
are  marked  with  the  canals  for  the  olfactory  nerves,  short 
and  oblique  before,  vertical  and  very  long  in  the  middle 
and  behind,  they  descend  for  about  half  the  depth  of  the 
plate,  and  become  converted  into  mere  grooves  ;  on  either 
side  of  this  septum  is  a  deep  channel,  which  forms  the  roof 
of  each  naris,  on  each  side  of  this  we  observe  an  irregular 
long  structure  which  consists  of  three  parts,  an  internal 
curved  lamina,  (the  superior  turbinated  bone,)  a  middle 
range  of  cells,  and  externally  towards  the  orbit  a  smooth 
square  plate,  the  os  planurn.     First,  the  turbinated  or  spongy 
bone  is  a  very  thin  plate  descending  at  first  vertically,  and 
then  bending  outwards,  and  rolled  upon  itself  for  nearly 
half  a  turn  ;  in  the  posterior  extremity  of  this  is  a  depres- 
sion or  sort  of  cleft,  which  is  called  the  superior  meatus  of 
the  nose,  this  channel  or  meatus  extends  along  the  poste- 
rior half  of  the  ethmoid,  it  is  closed  before,  except  in  a 
small  aperture  which  leads  into  the  posterior  ethmoid  cells; 
the  portion  of  the  turbinated  plate  which  extends  below 
this  fossa  is  named  the  middle  spongy  lone,  it  is  larger  than 
the   upper  portion,  more   curved,  and  very  concave  out- 
wardly, beneatb  this  is  a  deep  fossa  named  the  middle 
meatus  of  the  nose ;  second,  the  ethmoid  cells  are  external 
to  the  turbinated  plates,  bounded  above  by  the  cribriform 
plate,  and  externally  by  the  os  planum  and  os  unguis,  the 
cells  are  about  twelve  or  fourteen  in  number,  and  are  di- 
vided by  a  bony  septum  into  an  anterior  and  posterior  set, 
the  posterior  are  small,  and  open  into  the  superior  meatus, 
39 


446  DUBLIN    DISSECTOR. 

and  sometimes  one  of  the  uppermost  communicates  with  the 
sphenoid  sinus  oropens  intothe  fossa  of  its  turbinated  plate ; 
the  anterior  cells  are  larger  and  more  numerous,  they  open 
into  the  middle  meatus,  one  of  the  most  anterior  is  curved 
into  a  sort  of  tube,  the  infundibulum,  into  this  the  frontal 
sinus  opens  above,  and  it  terminates  before  the  orifice  of 
the  great  maxillary  sinus  or  antrum ;  all  these  cells  are 
lined  by  the  pituitary  membrane,  which,  however,  is  less 
vascular  and  thick  than  that  on  the  nasal  lamella  or  turbi- 
nated bones;  on  this  membrane,  particularly  that  covering 
the  superior  spongy  bone,  and  the  square  surface  before  it, 
the  external  olfactory  canals  chiefly  end  ;  from  the  lower 
surface  of  the  ethmoidal  cells  thin  plates  of  bone  often  de- 
scend very  irregularly  to  join  the  superior  maxillary.  Ex- 
ternal to  the  cells  on  each  side  is  the  third  part,  the  os  pla- 
num  or  orbital  plate,  very  smooth  and  polished,  articulated 
above  to  the  frontal,  before  to  the  lachrymal,  behind  to  the 
sphenoid,  and  below  tb  the  maxillary  and  palate  bones,  the 
upper  border  has  often  a  notch  or  two  which  assist  the 
frontal  in  forming' the  internal  orbital  holes.  The  ethmoid 
bone  contributes  to  form'the  base  of  the  cranium,  the  nose, 
and  the  orbits;  it  has  little  or  no  cellular  tissue  in  its  com- 
position except  in  the  turbinated  plates  and  the  crista  galli. 
It  is  developed  by  three  points  of  ossification,  one  for  the 
central  lamella  and  one  for  each  side,  the  latter  appear 
first,  the  turbinated  plates  are  not  distinct  until  five  years 
of  age :  it  is  joined  to  two  bones  of  the  cranium,  the  fron- 
tal and  sphenoid,  and  to  eleven  of  the  face,  the  nasal,  su- 
perior maxillary,  lachrymal,  palate,  interior  spongy,  and 
the  vomer. 

[There  are  no  muscles  attached  to  this  bone  ;  its  use  being  to  offer 
in  a  small  space  a  large  surface  upon  which  the  impression  of  odo- 
riferous particles  may  be  received.] 

The  sphenoid  bone  is  so  named  from  the  manner  in  which 
it'  is  wedged  into  the  base  of  the  skull,  in  the  middle  of 
which  it  is  placed,  it  is  articulated  to  all  the  bones  of  the 
cranium,  and  to  many  of  those  of  the  face,  it' is  of  a  very 
irregular  form,  and  has  been  compared  to  a  bat,  to  which 
it  bears  some  resemblance,  particularly  if  the  ethmoid  re- 
main attached  ;  it  may  be  divided  into  a  body  and  proces- 
ses, the  body  is  in  the  centre,  and  resembles  a  square  box; 
from  its  median  line  inferiorly  and  anteriorly  proceeds  the 
azygos  process,  or  the  rostrum,  which  is  received  between 
the  layers  of  the  vomer,  on  each  side  of  this  is  a  small 
groove  for  vessels ;  the  body  is  flat  and  rough  posteriorly 
for  attachment  to  the  basilar  process,  [of  the  os-occipitis] 
its  centre  is  hollowed  out  into  two  cavities  or  sinuses  which 
are  separated  by  a  septum,  which  is  continuous  with  the 


DUBLIN    DISSECTOR.  447 

azygos  process,  anteriorly  it  presents  the  two  small  round 
openings  of  the  sphenoid  sinus,  beneath  which  are  often 
found  two  small  triangular  bones,  the  spongy  or  turbinated 
bones  of  the  sphenoid,  or  of  Berlin;  the  superior  or  cere- 
bral surface  of  the  body  presents  several  remarkable  ap- 
pearances, it  is  hollowed  from  before  backwards  into  the 
deep  depression  called  sella-turcica,  this  lodges  the  pitui- 
tary gland,  and  is  perforated  by  several  holes  through 
which  small  vessels  pass  to  the  nose,  posteriorly  it  is 
bounded  by  a  thin  plate  which  rises  perpendicularly,  and 
has  a  slight  knob  at  each  angle  named  the  posterior  clinoid 
process,  to  each  of  these  the  extremity  of  the  convex  edge 
of  the  falx  is  attached  ;  anterior  to  the  sella  is  the  olivary 
eminence  or  middle  clinoid  process,  on  it  is  a  transverse  de- 
pression for  the  optic  commissure,  on  each  side  of  which 
are  the  anterior  clinoid  processes,  two  thick  tubercles  to  which 
the  extremity  of  the  concave  edge  of  the  tentorium  is  at- 
tached, each  of  these  is  perforated  by  the  optic  foramen, 
which  is  transversely  oval  and  transmits  the  ophthalmic 
artery  and  the  optic  nerve  ;  sometimes  the  anterior  is  uni- 
ted to  the  posterior  clinoid  process  by  bone,  and  somatimes 
to  the  olivary  process;  from  each  anterior  clinoid  process 
there  extends  forwards  and  outwards  a  thin  plate  of  bone, 
the  transverse  spine  or  lesser  win^,  or  wing  of  Ingrassias, 
this  is  united  anteriorly  to  the  frontal  bone,  and  forms  a 
part  of  the  orbit,  it  ends  in  a  point,  its  posterior  edge  is 
thick  and  rounded,  the  sphenoidal  fold  of  the  dura  mater  is 
attached  to  it,  and  botlr  occupy  the  fissure  of  Sylvius  on 
the  base  of  the  cerebrum  between 'its  anterior  and  middle 
lobes ;  each  side  of  the  sella  turcica  is  grooved  by  the  ca- 
rotid artery  ;  from  its  forepart  extends  a  small  plate  to  join 
the  ethmoid  bone,  (elhmoidal  process ;)  from  each  side  of  the 
body  the  ala  is  continued  outwards,  forwards,  and  upwards ; 
it  presents  three  surfaces,  one  anterior,  smooth  and  square, 
forms  part  of  the  outer  wall  of  the  orbit,  and  is  named  or- 
bital process,  another  is  elongated  and  concave,  and  together 
with  the  temporal  bone  supports  the  middle  lobe  of  the 
cerebrum  ;  the  third  or  external  surface  is  named  the  tem- 
poral process,  this  is  divided  into  two  by  a  crest,  the  upper 
part  forms  a  portion  of  the  temporal  fossa,  and  the  lower 
of  the  zygomatic  fossa,  some  fibres  of  the  temporal  and 
external  pterygoid  muscles  are  attached  to  the  crest  itself; 
from  the  posterior  part  of  each  wing  the  spinous  process  ex- 
tends backwards,  and  curves  a  little  downwards  and  out- 
wards, and  occupies  the  angle  between  the  squamous  and 
petrous  portions  of  the  temporal  bone,  it  terminates  in  a 
spine,  the  styloid  process,  on  the  inner  side  of  the  articulation 
of  the  lower  jaw ;  near  this  process  is  a  small  foramen 


448  DUBLIN    DISSECTOR. 

(spinosum)  which  transmits  the  middle  or  spinous  artery  of 
the  dura  mater,  anterior  to  this  is  the  foramen  ovale  opening 
directly  downwards  for  the  passage  of  the  inferior  maxil- 
lary nerve;  still  more  anterior  is  the  foramen  rotundum, 
which  leads  forwards  and  transmits  the  superior  maxillary 
nerve ;  between  the  lesser  and  great  wing  is  a  long  slit, 
the  foramen  lacerum  orbitale,  wide  internally,  narrow  exter- 
nally where  the  frontal  bone  sometimes  assists  in  closing 
it,  it  transmits  the  third,  fourth,  first  branch  of  the  fifth 
and  the  sixth  pair  of  nerves  from  the  cranium  to  the  or- 
bit :  from  the  angle  between  the  body  and  ala,  the  ptery- 
goid  plate  descends  perpendicularly,  internally  it  bounds 
the  posterior  naris,  externally  the  external  pterygoid  mus- 
cle is  attached  to  it,  anteriorly  the  palate  bone  is  con- 
nected to  it,  posteriorly  it  is  hollowed  into  the  pterygoid 
fossa,  which  lodges  the  internal  pterygoid  muscle,  and  in  a 
small  depression  internal  to  this  the  tensor  palati  muscle; 
this  fossa  thus  divides  this  process  into  two  plates,  the  ex- 
ternal is  broad  and  rough,  tho  internal  is  longer  and  nar- 
rower, and  ends  in  the  hamular  process,  a  small  delicate 
hook,  convex  inward?,  concave  outwards,  and  covered  by 
a  bursa,  round  this  the  tendon  of  the  tensor  palati  muscle 
turns:  in  the  inferior  notch  between  these  plates  the  palate 
bone  is  received  ;  above  the  internal  pterygoid  plate  is  the 
Vidian  hole  or  canal,  this  opens  anteriorly  on  the  inner  side 
of  the  foramen  rotundum,  into  the  spheno-maxillary  fossa, 
and  posteriorly  very  small  into  the  foramen  lacerum  ante- 
rius.  it  transmits  the  Vidian  nerve  and  vessels. 

The  structure  of  the  sphenoid  bone  is  very  compact, 
except  the  body  which  is  cellular ;  the  latter  about  ten 
years  of  age  undergoes  the  process  of  absorption,  whereby 
the  cavities  called  the  sphenoid  sinuses  are  formed  ;  these 
open  into  the  upper  and  back  part  of  the  nose  ;  in  front  of 
them  in  the  adult  is  a  small  curved  plate  of  bone,  the 
sphenoidal  turbinated  bone,  it  is  of  a  pyramidal  form,  the 
base  anteriorly  connected  to  the  posterior  ethmoid  cells, 
the  apex  posteriorly,  and  joined  to  the  forepart  of  the 
sinus,  it  lies  above  the  spheno-palaiine  foramen,  a  hole  which 
is  below  the  body  of  the  sphenoid,  and  between  the  orbital 
processes  of  the  palate  bone  ;  this  hole  leads  from  the 
nose  to  the  spheno-  or  ptery  go -maxillary  space  ;  these  su- 
perior spongy  bones  are  wanting  in  the  child  and  some- 
times in  the  adult.  The  sphenoid  is  articulated  to  the 
seven  bones  of  the  cranium  and  to  five  of  the  face,  viz., 
the  two  malar,  two  palate,  and  the  vomer,  and  in  some 
cases  to  the  superior  maxillary  by  the  pterygoid  plates, 
the  palate  bones  however  in  general  intervene ;  the  pro- 
cesses enumerated  are  twenty -seven,  viz.,  five  clinoid,  ono 


DUBLIN    DISSECTOR.  449 

ethmoidal,  two  lesser  wings,  one  vomer  or  azygos,  two 
spongy  or  triangular,  two  great  wings,  two  temporal,  two 
orbital,  two  spinous,  two  styloid,  four  pterygoid,  and  two 
hamular;  the  foramina  are  fourteen  proper  and  eight  com- 
mon ;  the  proper  are,  two  optic,  two  lacerated  orbital,  two 
round,  two  oval,  two  spinal,  two  Vidian,  arid  the  two  si- 
nuses :  the  common  are,  two  foramina  lacera  antica  basis- 
cranii,  two  spheno-maxillary  fissures,  one  in  each  orbit 
bounded  by  the  orbital  plates  of  the  sphenoid,  malar, 
maxillary,  and  palate  bones,  two  spheno-palatine,  and  two 
posterior  palatine  canals  between  the  pterygoid  processes 
and  the  superior  maxillary  tuberosities.  At  birth,  the 
sphenoid  bone  consist  of  three  pieces,  one  is  the  body  to 
which  the  clinoid  processes  and  lesser  wings  are  attached, 
the  lateral  pieces  consist  of  the  pterygoid  processes  and  the 
great  wing  of  each  side. 

[Muscles.  Twelve  pair  are  attached  to  this  bone ;  and  all  arise 
from  it,  the  temporal,  external  and  internal  pterygoids,  constrictor 
pharyngis  superior,  tensor  palati,  laxator  tympani,  levator  palpebroe 
auperioris,  the  superior  oblique  and  four  recti  muscles  of  the  eye.] 

The  bones  of  the  cranium  are  connected  to  each  other 
by  suture,  that  is,  the  edge  of  each  is  serrated  or  cut  into 
irregular  teeth  like  processes,  these  indigitate  or  lock  into 
each  other,  so  as  to  unite  the  two  edges  in  a  very  strong 
and  motionless  manner,  the  indentations  are  irregular  nnd 
oblique  in  very  thick  bones,  but  where  the  edges  are  thin, 
the  suture  is  more  straight  and  regular  ;  they  are  more  dis- 
tinct in  the  young  than  in  the  old,  and  on  the  outer  than 
the  inner  surface  of  the  cranium  ;  there  are  seven  sutures 
noticed  by  most  anatomists,  (some  however  unnecessarily 
enumerate  a  greater  number,)  the  sphenoidal,  ethmoidal, 
coronal,  sagittal,  lambdoid,  and  two  squamous.  The  sphe- 
noidal suture  is  very  extensive,  it  follows  the  irregular  edge 
of  the  sphenoid  bone,  and  connects  it  to  the  occipital,  the 
temporal,  inferior  angle  of  the  parietal,  the  frontal,  and  the 
ethmoid.  The  ellimoidal  suture  in  like  manner  encircles  the 
ethmoid  bone  and  connects  it  to  the  frontal.  The  frontal, 
or  coronal  suture  proceeds  .from  the  upper  extremity  of  the 
sphenoidal  about  an  inch  behind  the  external  angle  of  the 
os  front  is,  ascends  vertically  inclining  a  little  backwards, 
and  then  descends  to  the  same  point  on  the  opposite  side, 
it  connects  the  frontal  and  parietal  bones  in  the  manner  be- 
fore explained.  The  sagittal  suture  leads  from  the  superior 
angle  of  the  occipital  bone  directly  forwards  between  the 
two  parietal  to  the  centre  of  the  coronal  suture,  and  is 
sometimes  continued  along  the  median  line  of  the  frontal 
bone  down  to  the  nose.  The  lambdoid  suture  extends  on 
38* 


450  DUBLIN    DISSECTOR. 

either  side  from  the  posterior  extremity  of  the  sagittal  su- 
ture, downwards  and  forwards  to  the  mastoid  process  of 
the  temporal  bone  ;  a  suture  named  the  additame.ntum  of  the 
lambdoid  continues  down  between  this  process  and  the  occi- 
pital bone  as  far  as  the  foramen  lacerum  posterius;  the 
lumbdoid  suture  is  very  rough,  and  frequently  contains 
ossa  triquetra  of  very  irregular  size,  it  connects  the  occipi- 
tal and  the  two  parietal  bones ;  the  additamentum  is  very 
little  serrated,  but  presents  uneven  thick  edges,  it  connects 
the  occipital  to  the  mastoid  portion  of  the  temporal  bone, 
the  mastoid  hole  is  frequently  in  it,  it  nearly  corresponds 
to  the  lateral  sinus.  The  squamous  suture  on  each  side  is 
continued  from  the  extremity  of  the  sphenoidal  in  an  arched 
direction  upwards  and  backwards,  as  far  as  the  inferior 
angle  of  the  parietal,  it  is  then  continued  under  the  name 
of  additamentum  of  the  squamous  suture,  directly  backwards 
for  about  an  inch  ;  the  structure  of  the  squamous  differs 
from  that  of  the  other  sutures,  the  bones  are  not  serrated 
but  thin  and  scaly,  and  overlap  each  other,  it  unites  the 
temporal  to  the  parietal;  the  additamentum  is  serrated  and 
connects  the  inferior  angle  of  the  parietal  to  the  upper  part 
of  the  mastoid  portion  of  the  temporal  bone,  it  corresponds 
to  the  course  of  the  lateral  sinus  internally ;  a  small  os 
triquetrum  is  sometimes  found  at  the  anterior  part  of  this 
suture,  and  seldom  in  any  other  situation. 

[The  bones  of  the  cranium  belong  for  the  most  part  to  the  class 
of  flat  bones,  and  are  developed  by  fibres  radiating  from  a  centre. 
In  the  adult,  the  flat  bones  of  the  head  consist  of  three  laminae,  an 
external  table  of  compact  tissue,  an  internal  table  of  compact  tissue, 
more  dense  and  brittle  than  the  other,  and  hence  called  the  tabula 
vitrea,  arid  a  middle  lamina  of  spongy  tissue,  the  diploe  ;  this  does 
not  exist  in  the  infant  and  child,  but  subsequently  is  developed,  appa, 
rently  at  the  expense  of  the  contiguous  surfaces  of  the  compact  ta- 
bles, which  seem  to  recede  from  each  other,  so  as  to  form  the  diploe 
and  the  frontal  sinuses.  In  the  old  subject,  the  diploe  is  absorbed, 
and  the  two  compact  tables  fall  together  again  ;  in  advanced  life  the 
sutures  are  liable  to  become  obliterated,  so  that  the  bones  form  a 
solid  inseparable  mass ;  a  suture  may  be  confounded  with  a  fissure. 
All  the  bones  of  the  cranium  may  be  fractured  ;  but  those  parts 
above  a  line  subtending  the  supra-orbital  arches,  the  external  open- 
ings of  the  ears,  and  the  occipital  protuberance  are  of  course  most 
exposed  to  external  violence  ;  those  parts  in  the  base  of  the  cranium 
may  be  fractured  by  very  great  violence,  or  by  a  counter  fissure. 
The  internal  table  may  be  fissured,  the  external  being  entire  ;  and 
both  tables  may  be  driven  in  without  a  division  of  the  soft  parts  over 
them.  There  are  some  situations  in  which  we  are  directed  not  to 
apply  the  trephine,  as  over  the  longitudinal  sinus,  over  the  trunk  of 
the  middle  rneningeal  artery,  &,c. ;  but  under  certain  circumstances 
we  must  operate  in  those  places  ;  the  trephine  cannot  be  applied  be- 


DUBLIN    DISSECTOR.  451 

low  the  superior  transverse  ridge  of  the  occipital  bone.  After  a 
piece  of  bone  has  been  removed  by  the  trephine,  its  place  is  subse- 
quently supplied  by  a  fibro-cartilacrinous  membrane,  of  which  there 
are  some  fine  specimens  in  the  collection  of  Dr.  Sabine.j 

OF    THE    SKULL    IN    GENERAL. 

THE  outer  surface  of  the  skull  presents  four  regions,  the 
superior  is  smooth  and  even,  has  no  remarkable  appearance 
deserving  more  particular  attention  ;  the  lateral  regions  arc 
each  divided  into  two,  anterior  or  temporal,  and  the  poste- 
rior or  mastoid  ;  the  inferior  region  extends  from  the  nasal 
notch  to  the  occipital  protuberance,  and  is  bounded  late- 
rally by  the  zygomatic  arches,  and  by  a  ridge  which  is 
continued  from  these  processes  round  the  skull  with  but 
little  interruption ;  this  region  may  be  divided  into  threo 
portions,  anterior,  middle,  and  posterior ;  the  anterior  ex- 
tends from  the  superciliary  ridges  of  the  os  frontis  to  the 
roots  of  the  pterygoid  processes  of  the  os-sphenoides  ;  it 
presents  the  nasal  spine  and  process  of  the  os  frontis,  the 
ethmoid  bone,  the  orbital  plates  of  the  os  frontis,  bounded 
by  its  angular  processes  before,  and  by  the  orbitar  plates 
of  the  sphenoid  behind ;  in  this  division  are  the  supra-or- 
bital, the  anterior  and  posterior  orbital  holes,  the  openings 
of  the  frontal  and  ethmoid  cells,  the  optic  and  lacerated 
holes  of  the  orbits,  the  Vidian  canals  and  the  foramina  ro- 
tunda. The  middle  division  extends  from  the  roots  of  the 
pterygoid  to  the  styloid  processes  of  the  temporal  bones,  it 
presents  the  azygos  process,  the  basilar  process  of  the  os 
occipitis,  the  anterior  points  of  the  petrous  portions  of  the 
temporal  bones ;  the  spinous  processes  of  the  sphenoid, 
and  the  glenoid  cavities  of  the  temporal  bones.  The  holes 
in  this  division  are  the  oval,  spinous,  carotid,  external,  au- 
ditory, glenoidal,  and  the  Eustachian  tubes.  The  posterior 
division  extends  from  the  styloid  processes  of  the  temporal 
to  the  tuberosity  of  the  occipital  bone  ;  it  presents  the  fo- 
ramen magnum,  the  two  condyles,  the  jugular  ridge,  the 
styloid  processes  of  the  temporal  bones,  surrounded  by 
their  vaginal  processes,  the  mammillary  processes,  the 
digastric  pits,  the  inferior  and  superior  transverse  arches, 
the  spine,  protuberance,  and  pits  of  the  occipital  bono  ; 
the  foramina  in  this  division  are  the  stylo-mastoid,  mas- 
toid, magnum,  lacera  postica,  anterior  and  posterior  con- 
dyloid. 

The  skull  is  divided  internally  into  the  arch  or  vault  and 
the  base  ;  on  the  vault  is  to  be  observed  the  sulcus  for  the 
longitudinal  sinus,  the  frontal  crest,  the  grooves  for  the  mid- 
dle arteries  of  the  dura  mater,  the  depressions  for  the  con- 
volutions of  the  brain,  and  for  the  granulations  or  glandulse 


452  DUBLIN    DISSECTOR. 

Pacchionse ;  the  base  of  the  skull  is  very  uneven,  and  pre- 
sents three  portions,  regions,  or  fossae  on  different  planes, 
the  anterior  or  frontal,  the  middle  or  spheno-temporal,  and 
the  posterior  or  occipital ;  the  first  is  formed  of  the  orbital 
plates  of  the  frontal  bone,  the  cribriform  plate  of  the  eth 
moid,  and  the  lesser  wings  of  the  sphenoid  ;  the  foramina 
in  this  division  are  the  cascum,  olfactory,  and  optic.  The 
second  division  is  bounded  before  by  the  transverse  spinous 
processes  of  the  sphenoid,  on  the  sides  by  the  squamous 
portions  of  the  temporal,  and  behind  by  the  superior  angles 
of  the  petrous  portions  of  the  same  bone,  and  by  the  poste- 
rior clinoid  processes  of  the  sphenoid  ;  in  the  middle  is  the 
sella  turcica,  on  each  side  of  which,  but  below  it,  is  a  groove 
for  the  carotid  artery,  and  for  the  cavernous  sinus,  and  be- 
low this  is  a  shallow  groove  tfor  the  superior  maxillary 
nerve;  further  out  on  each  side,  are  the  cavities  to  lodge 
the  middle  lobes  of  the  brain ;  and  on  the  anterior  surface 
of  the  petrous  bones  are  seen  the  juttings  of  the  vertical 
semicircular  canals.  The  foramina  in  this  .division  are,  the 
foramina  lacera  orbitaria  superiora,  rotunda,  ovalia,  caro- 
tica,  spinosa,  lacera  basis  cranii  anteriora,.  and  innominata 
or  hiatus  Fallopii.  The  third  or  occipital  portion  is  bounded 
before  by  the  basilar  process,  and  by  the  posterior  surface 
of  the  petrous  bones,  and  behind  by  the  occipital,  it  pre- 
sents the  basilar  process,  the  foramen  magnum,  the  perpen- 
dicular ridge  of  the  occipital  crossed  by  the  transverse,  by 
which  this  bone  is  divided  into  four  fossae,  the  superior  an- 
gles of  the  petrous  bones  having  a  shallow  groove  for  the 
superior  petrosal  sinuses,  the  transverse  occipital  ridge,  with 
a  deep  one  for  the  lateral  sinuses,  which  last  are  continued 
over  the  inferior  angles  of  the  parietal  bones,  and  thence 
descend  inwards  along  the  mastoid  portions  of  the  temporal 
bone,  and  then  again  groove  the  occipital  bone,  and  pass 
forwards  on  it  to  the  posterior  foramina  lacera  ;  the  per- 
pendicular ridge  is  grooved  above  for  the  longitudinal  sinus, 
which  terminates  sometimes  in  the  left,  and  at  other  times 
in  the  right  lateral  sinus ;  the  same  ridge  below  the  tento- 
rium  gives  attachment  to  the  falx  minor,  and  is  slightly 
grooved  for  the  occipital  sinuses.  The  foramina  in  thus 
division  are  the  foramina  auditiva,  aqueductus  vestibulo- 
rum,  foramina  lacera  postica,  foramen  magnum,  foramina 
condyloidea  antica  and  postica. 

THE    BONES    OF    THE    FACE. 

THESE  consist  of  six  pair  and  two  single  bones  ;  the  six 
pair  are  the  malar,  superior  maxillary,  lachrymal,  nasal, 
palatine,  and  inferior  spongy  ;  the  two  single  bones  are  the 
vomer  and  the  inferior  maxillary. 


DUBLIN    DISSECTOR.  453 

The  malar  or  cheek  bone  is  placed  at  the  outer  and  under 
part  of  the  orbit,  and  forms  the  prominence  of  the  cheek  ; 
it  is  of  an  irregular  square  form,  convex  externally,  and 
covered  by  the  skin  and  orbicularis  palpebrarum  ;  it  pre- 
sents one  or  two  small  holes  for  vessels  and  nerves;  its 
upper  and  outer  edge  is  named, [superior  or~\external  obital 
procsss,  and  joins  the  frontal  bone  ;  its  inner  end  is  cut  off 
obliquely  and  serrated,  is  attached  to  and  overlaps  the 
maxillary  bone,  this  is  the  maxillary  process;  its  anterior 
edge  between  these  two  processes  is  round,  smooth,  and 
concave,  forms  about  one-third  of  the  base  or  circumference 
of  the  orbit,  and  ends  internally  in  a  long  angle,  named  the 
inferior  orbital  process ;  the  lower  edge  is  thick  and  uneven, 
and  gives  attachment  to  the  masseter  muscle,  it  ends  poste- 
riorly in  the  zygomatic  process,  which  passes  backwards,  and 
terminates  in  a  serrated  edge  which  supports  the  zygomatic 
process  of  the  temporal  bone;  behind  this  the  malar  bone 
is  smooth,  and  forms  part  of  the  temporal  fossa  ;  from  the 
posterior  surface  a  thin  plate  extends  into  the  orbit,  and  is 
named  the  internal  orbital  process  ;  the  posterior  edge  of  this 
is  notched  to  close  the  spheno-maxillary  fissure  anteriorly. 
The  malar  bone  is  thick,  strong,  and  cellular ;  it  is  well 
developed  in  the  foetus.  It  is  joined  to  four  bones,  the 
frontal,  sphenoid,  temporal,  and  superior  maxillary  ;  the 
processes  are  five,  the  superior,  inferior,  and  internal  orbi- 
tal, the  malar,  and  zygomatic ;  the  foramina  are  two  or 
three  proper  and  one  common,  viz.,  the  spheno-maxillary 
fissure,  or  the  foramen  lacerum  orbitale  inferius. 

[Muscles.  Four  muscles  arise  from  this  bone,  the  zygomatici  ma- 
jor and  minor,  the  masseter,  and  the  temporal ;  the  orbicularis  pal. 
pebrarum  spreads  over  it.] 

The  superior  maxillary  Imne  is  of  a  very  irregular  figure, 
and  attached  to  all  the  bones  of  the  upper  jaw ;  it  forms 
part  of  the  front  of  the  face,  a  portion  of  the  orbit,  nose, 
and  palate ;  it  may  be  divided  into  the  body  and  processes. 
The  body  is  concave  anteriorly,  to  form  the  infra-orbital  or 
canine  fossa,  in  the  upper  part  of  which  is  the  infra-orbital 
hole ;  it  is  bounded  externally  and  above  by  a  rough  ser- 
rated surface,  the  malar  process,  which  is  smooth  and  hol- 
lowed out  behind  for  the  temporal  muscle  ;  springing  from 
the  inner  and  upper  part  of  the  body,  is  the  nasal  process 
of  a  pyramidal  form,  perforated  by  one  or  two  small  holes 
for  vessels,  serrated  above  to  join  the  os  frontis,  prominent 
below,  slightly  grooved  anteriorly  to  receive  the  nasal  bone 
and  the  alar  cartilage,  and  deeply  grooved  behind  to  form 
part  of  the  lachrymal  fossa  and  duct:  its  internal  surface 
forms  part  of  the  nasal  fossa,  and  is  connected  to  the  eth- 
moid bone  above,  below  this  is  a  channel  that  leads  to  the 


454  DUBLIN    DISSECTOR. 

middle  meatus,  and  inferior  to  this  is  a  crest  for  the  spongy 
bone ;  between  the  nasal  and  malar  processes  is  the  orbital 
plate,  of  a  triangular  form,  the  base  joined  to  the  ethmoid, 
lachrymal,  and  palate  bones;  this  process  looks  down- 
wards and  forwards;  its  outer  and  posterior  edge  bounds 
the  spheno-maxillary  fissure :  the  infra-orbital  canal,  which 
runs  along  it  in  a  direction  forwards  and  inwards,  lodges 
the  vessels  and  nerves  of  that  name  ;  this  canal  divides 
anteriorly  into  two,  the  smaller  is  the  anterior  dental,  which 
descends  in  the  anterior  wall  of  the  antrum,  where  it  teiv 
minates  by  communicating  with  the  anterior  alveoli,  the 
other  or  the  proper  infra-orhifal  canal  is  wider,  and  ends  in 
the  infra-orbital  hole  ;  the  edge  of  the  bone  above  this  hole 
is  round  to  form  part  of  the  contour  of  the  orbit,  behind 
which  the  inferior  oblique  muscle  of  the  eye  arises ;  behind 
and  below  this  plate  is  the  tuberosity,  this  is  more  prominent 
in  the  young,  as  it  contains  the  last  molar  tooth,  after  the 
protrusion  of  which  it  diminishes,  near  this  are  three  or 
lour  small  holes,  the  posterior  dental  canals,  which  lead  to 
the  posterior  alveoli ;  beneath  the  orbital  plate,  the  body 
of  the  bone  is  excavated  into  a  large  cavity,  the  antrum 
highmorianum,  [or  maxillary  sinus,]  of  somewhat  a  trian- 
gular figure,  the  base  towards  the  nose,  the  apex  towards 
the  malar  process  ;  this  is  the  largest  sinus  connected  with 
the  nose,  it  is  sometimes  divided  by  septa  as  well  as  by 
the  anterior  dental  canal  into  two  or  more  cells  ;  the  infra- 
orbital  canal  runs  along  its  roof,  through  the  floor,  one  or 
two  of  the  molar  alveoli  project  and  sometimes  open,  the 
canine  fossa  is  in  front  of  it,  and  the'tuber  bounds  it  behind, 
this  cavity  is  lined  by  the  membrane  of  the  nose  ;  in  the 
skeleton  the  opening  in  its  base  is  very  large  and  irregular, 
but  in  the  natural  state  it  is  contracted  by  the  ethmoid 
bone  above,  by  the  palate  bone  behind,  and  by  the  inferior 
spongy  bone  below,  also  by  the  lining  membrane  of  the 
nose ;  it  opens  by  one  or  two  small  oblique  openings  into 
the  middle  meatus  of  the  nose,  anterior  to  which  is  the  in- 
fundibulum,  a  deep  groove  leading  downwards,  backwards, 
and  inwards,  from  the  frontal  sinus  and  the  anterior  eth- 
moid cells,  and  opening  into  the  middle  meatus;  the  body 
of  this  bone  is  bounded  below  by  a  strong  horizontal  plate, 
the  palatine  process,  the  upper  surface  of  which  is  smooth 
and  concave,  and  forms  the  floor  of  the  nose,  the  lower  is 
rough,  and  forms  the  roof  of  the  mouth ;  it  is  thick  before, 
thin  and  serrated  behind  to  join  the  palate  bone,  internally 
it  is  thick  and  rough,  and  joins  the  opposite  bone,  by  a  su- 
ture, in  the  anterior  part  of  which  is  the  anterior  palatine 
canal,  which  opens  inferiorly  on  the  palate  by  the  foramen 
incisivum,  and  superiorly  by  two  distinct  holes,  one  in  each 


DUBLIN    DISSECTOR.  455 

nostril ;  this  internal  edge  is  raised  so  as  to  form  the  nasal 
spine  or  crest  to  receive  the  vomer,  anteriorly  this  projects 
so  as  to  form  the  anterior  nasal  spine,  to  which  the  cartila- 
ginous septum  of  the  nose  is  attached;  between  this  and 
the  nasal  process  the  bone  is  very  concave  and  forms  the 
anterior  opening  of  the  nares. 

The  palate  plate  is  bounded  anteriorly  and  externally 
by  the  curved  alveolar  edge  or  process;  this  is  very  thick, 
particularly  behind,  and  is  divided  into  several,  generally 
eight,  conical  cavities  for  the  teeth  ;  the  partitions  between 
these  are  formed  of  dense  cellular  texture  which  is  less 
compact  posteriorly.  The  superior  maxillary  bone  is  con- 
nected to  two  bones  of  the  cranium,  the  frontal  and  eth- 
moid, and  to  seven  bones  of  the  face,  the  nasal,  lachrymal, 
malar,  palate,  inferior  spongy,  vomer,  and  to  its  fellow  of 
the  opposite  side,  also  to  the  teeth  ;  it  is  sometimes  con- 
nected to  the  pterygoid  processes  of  the  sphenoid.  The 
processes  are  eight,  the  nasalr  orbital,  malar,  tuberosity, 
alveolar,  palatine,  nasal  crest,- and  nasal  spine :  the  fora- 
mina are  three  proper  and  four  common  ;  the  proper  are 
the  infra-orbital,  the  foramen  antri,  and  foramen  incisivum  ; 
the  common  are  the  spheno-maxillary  fissure,  the  posterior 
palatine  hole  or  canal,  the  anterior  nares,  and  the  nasal  or 
lachrymal  duct ;  this  bone  is  well  developed  in  the  foetus,. 
with  the  exception  of  the  alveoli  and  sinus,  the  former  com- 
mence about  the  end  of  the  first  year,  the  latter  about  the 
seventh. 

[Muscles.  Eight  are  attached  to  this  bone  ;  seven  arise  from  it;  the 
obliquus  oculi  inferior,  levator  and  depressor  labii  superioris  alseque 
nasi,  levator  anguli  oris,  compressor  nasi,  buccinator  and  masseter ; 
the  orbicularis  palpebrarum  Is  inserted  into  it.] 

The  palate  bone  is  situated' at' the  outer  and  back  part  of 
the  nose,. bet, ween  the  pterygoid  processes  [of  the  sphenoid], 
and  the  superior  maxillary  bone,  it  is  of  a  very  irregular 
figure  and  may  be  divided  imo  four  parts;  first,  the  hori- 
zontal or  palate  plate;  second,  the  nasal  or  perpendicular 
plate,  at  the  lower  and  outer  angle  of  which  is,  third,  the 
pterygoid  process;,  and  fourth,  at  the  upper  extremity  of 
the  nasal  is  the  orbital  portion.-  The  palate  process  or  plate 
is  nearly  square,  flat,  and  rough  below,  smooth  above,  and 
concave  from  side  to  side  to  form  part  of  the  floor  of  the 
nose,  posteriorly  it  has  a  thin  edge  to  which  the  velum 
palati  is  attached ;  its  anterior  border  is  serrated  to  join 
the  palate  plate  of  the  maxillary  bone,  its  inner  edge  rises 
into  a  spine  or  crest  to  support  the  vomer,  and  is  continued 
posteriorly  into  the  posterior  nasal  spine;  its  centre  is  thinner 
than  its  edges.  The  nasal  process  or  vertical  plate  is  broad 
and  thin,  rests  partly  on  the  maxillary  bone,  its  inner  or 


456  DUBLIN    DISSECTOR. 

nasal  surface  forms  part  of  the  nasal  fossa,  and  is  marked 
by  two  depressions  which  assist  in  forming  the  lower  and 
middle  meatus  of  the  nose,  the  ridge  between  these  sup- 
ports the  lower  spongy  bone,  externally  it  is  uneven  and 
grooved  for  the  posterior  palatine  vessels  and  nerves  :  the 
anterior  edge  of  this  plate  is  thin  and  brittle,  and  prolonged 
for  some  way  over  the  antrum,  the  posterior  edge  joins  the 
pteryguid  processes  [of  the  sphenoid.]  The  luberosity  or  the 
pterygoid  process  arises  from  the  lower  and  outer  angle,  is 
thick  and  wedge-shaped,  it  inclines  backwards  and  out- 
wards, and  presents  three  fossae,  one  at  each  side  for  each 
pterygoid  plate  [of  the  sphenoid,]  and  one  in  the  middle 
which  assists  in  forming  the  pterygoid  fossa ;  the  inner- 
most of  these  fossa?  is  the  deepest :  this  process  is  perfo- 
rated by  one  or  two  small  holes  which  lead  from  the  pala- 
tine canal ;  at  the  upper  extremity  of  the  nasal  plate  arc 
the  orbital  and  sphenoidal  processes,  separated  from  each 
other  by  a  deep  notch  :  the  orbital  is  the  larger  and  ante- 
rior of  the  two,  it  is  triangular  and  bent  a  little  outwards, 
it  appears  in  the  most  remote  part  of  the  floor  of  the  orbit, 
where  it  is  joined  to  the  maxillary  bone  by  one  edge,  to  the 
os  planum  by  the  second,  while  the  third  enters  into  the 
spheno-maxiilary  fissure ;  the  sphenoidal  or  posterior  or- 
bital process  is  smaller,  and  is  articulated  to  the  body  and 
spongy  plate  of  the  sphenoid  bone ;  both  these  processes 
are  cellular,  the  cells  communicate  with  those  of  the  eth- 
moid and  sphenoid  bones;  the  notch  between  these  two 
processes  forms  the  spheno-palatine  hole.  The  palate 
bone  is  joined  to  the  maxillary,  inferior  spongy,  vomer, 
sphenoid  and  ethmoid,  and  to  the  opposite  palate  bone ;  it 
is  composed  of  thin  compact  substance,  and  is  well  formed 
in  the  foetus ;  its  processes  are  seven,  palate,  nasal,  ptery- 
goid, orbital,  sphenoidal,  posterior  nasal  spine  and  crest ; 
its  foramina  are  one  proper  and  three  common.  The  pro- 
per is  the  posterior  palatine  hole  or  holes ;  the  common 
are  the  posterior  palatine  or  ptery go-maxillary  canal,  the 
spheno-maxillary  fissure,  or  the  foramen-lacerum  orbitale 
inferius,  and  the  spheno-palatine  hole;  the  latter  is  above 
the  nasal  plate,  below  the  body  of  the  sphenoid,  and  be- 
tween the  orbital  processes  of  the  palate  bone,  it  transmits 
the  nasal  nerve  and  artery  from  the  spheno-maxillary  fossa 
into  the  nose. 

[Muscles.  With  the  exception  of  the  azygos  or  motor  uvulae  no 
muscle  arises  to  any  extent  from  this  bone  ;  the  tensor  palati  and 
pterygoid  muscles  are  slightly  attached  to  it.] 

The  inferior  spongy  or  turbinated  bone,  placed  on  the  lower 
part  of  the  outer  side  of  the  nose,  elongated  from  before 


DUBLIN    DISSECTOR.  457 

backwards,  presents  a  wrinkled  or  a  rugged  surface,  is 
convex  towards  the  nose,  concave  outwards,  its  lower  edge 
is  loose,  spongy,  and  curled  outwards  ;  the  upper  edge  is 
uneven,  thin,  and  joined  to  the  unguis,  and  to  the  maxil- 
lary and  palate  bones  ;  it  is  connected  to  the  unguis  by  a 
thin  pyramidal  process,  which  completes  the  nasal  duct ; 
it  is  also  in  general  united  to  a  descending  oblique  process 
of  the  ethmoid,  it  is  composed  of  very  thin  brittle  sub- 
stance; marked  with  pores  and  little  spines. 

[No  muscles  are  attached  to  this  bone,  or  to  the  vomer,  these  and 
the  ethmoid  being  the  only  bones  of  the  head  and  face  which  have 
no  muscular  relations.] 

The  os  unguis  or  lachrymal  bone  is  placed  at  the  inner  and 
orepart  of  the  orbit ;  below  the  os  frontis,  behind  the 
lasal  process  of  the  superior  maxillary  and  before  the. 
thmoid  bone,  it  is  of  an  oblong  square  shape,  and  very 
hin,  it  covers  the  anterior  ethmoidal  cells ;  externally  it  is 
ivided  by  a  perpendicular  ridge,  which  terminates  below 
n  a  little  hook-like  process,  into  two  unequal  plates,  the 
losterior  or  orbital  plate  is  short  and  broad,  the  anterior 
achrymal  plate  is  concave,  long,  and  narrow,  and  forms  part 
)f  the  lachrymal  or  nasal  fossa  and  duct.  The  os  unguis 
s  joined  above  to  the  internal  angular  and  orbitar  pro- 
:esses  of  the  os  frontis ;  behind  to  the  os  planum  of  the 
'thmoid,  below  to  the  orbitar  plate  of  the  maxillary,  before 
o  the  nasal  process  of  the  same,  and  before  and  below  to 
he  inferior  spongy  bone;  its  structure  is  thin  but  com- 
Dact. 

[This  bone  is  sometimes  wanting,  and  its  place  is  then  supplied 
iy  the  superior  maxillary  and  ethmoid  bones :  this  bone  co-exists 
with  the  lachrymal  secretion,  and  is  said  not  to  be  found  in  those  ani- 
mals, who,  living  in  water,  have  no  lachrymal  gland.  The  tensor 
arsi  arises  from  this  bone.] 

The  nasal  bones  are  situated  beneath  the  nasal  process  of 
he  frontal  and  between  the  nasal  processes  of  the  superior 
maxillary  bones,  they  are  small,  narrow,  and  thick  above, 
hin  and  expanded  below ;  they  form  the  bridge  of  the 
nose ;  the  external  surface  of  each  is  slightly  concave  from 
above  downwards,  convex  from  side  to  side,  and  perforated 
with  one  or  two  small  holes ;  the  internal  surface  is  con- 
cave and  grooved  for  the  nasal  nerves ;  the  superior  mar- 
jin  is  thick  and  deeply  denticulated  to  join  the  nasal 
process  and  spine  of  the  frontal  and  the  nasal  plate  of  the 
ethmoid  bones ;  its  external  edge  is  grooved  and  received 
into  the  nasal  process  of  the  superior  maxillary,  its  inner 
edge  is  flat  to  join  with  its  fellow,  and  its  lower  edge  is  thin 
and  irregular,  joins  the  alar  cartilages,  and  is  notched  for 
39 


458  DUBLIN    DISSECTOR. 

the  passage  of  the  nasal  branches  of  the  ophthalmic 
nerve. 

[Muscles.  No  muscles  are  attached  to  this  bone,  but  the  pyrami- 
dalis  and  compressor  nasi  are  inserted  into  the  integuments  over  it.] 

The  vomer ;  this  azygos  bone  resembles  a  ploughshare; 
it  stands  in  the  median  line,  although  it  often  bends  a  little 
to  one  side,  is  thin  and  flat,  and  covered  by  the  pituitary 
membrane,  it  presents  four  edges ;  the  upper  or  sphenoidal 
is  hollowed  to  receive  the  azygos  process ;  the  anterior  is 
slightly  grooved  to  receive  the  ethmoidal  lamina  and  the 
nasal  cartilage ;  the  posterior  or  pharyngeal  is  round  and 
smooth  and  unattached  ;  the  inferior  or  palatine  edge  is  the 
longest,  and  is  received  between  the  laminae  of  the  nasal 
crest  of  the  maxillary  and  palate  bones ;  it  is  attached  to 
the  maxillary,  palate,  ethmoid,  and  sphenoid  bones,  also  to 
the  turbinated  bones  of  the  latter ;  its  structure  is  compact, 
but  thin  and  transparent :  all  the  bones  of  the  upper  jaw 
are  well  developed  in  the  foetus. 

[The  bones  of  the  upper  jaw  generally  will  only  be  fractured  by 
very  severe  violence  ;  but  the  nasal  bones  are  most  exposed  and 
most  frequently  broken  ^congenital  deficiencies  are  occasionally  met 
with,  as  in  cleft  palate,  in  which  parts  of  the  superior  maxillary  and 
palate  bones  are  wanting,  and  the  vomer  is  either  wanting,  or  bent 
to  one  side.  In  acephalous  monsters  the  bones  of  the  face  may  be 
perfect,  but  there  is  great  deformity  and  deficiency  in  the  cranial 
bones.  Large  masses  of  the  upper  jaw  extending  even  to  the  sinus 
and  orbit  have  been  successfully  removed  on  account  of  malignant 
disease.] 

The  inferior  maxillary  bone,  or  the  lower  jaw,  is  the  largest 
of  the  facial  bones,  it  is  of  a  semicircular  figure  situated 
at  the  lower  part  of  the  face  and  extending  along  its  sides 
and  back  part  to  the  base  of  the  skull ;  it  is  divided  into 
the  body  or  chin,  the  sides,  the  rami,  and  the  processes. 
The  body  is  the  anterior  prominent  portion  with  a  vertical 
ridge  in  the  centre,  the  symphysis,  or  the  line  of  union  of  the 
two  symmetrical  pieces  of  which  this  bone  in  infancy  con- 
sisted ;  inferiorly  the  body  projects  into  the  mental  process 
or  chin,  above  this  on  each  side  is  a  depression  for  the  mus- 
cles of  the  lower  lip,  external  to  which  and  looking  back- 
wards is  the  oval  oblique  opening  of  the  dental  canal,  call- 
ed the  mental  hole,  through  which  a  vessel  and  nerve  of  the 
same  name  pass ;  posteriorly  the  body  of  the  bone  is  con- 
cave, and  lined  above  by  the  mucous  membrane,  in  the 
middle  it  presents,  in  the  line  of  the  symphysis,  a  chain  of 
eminences,  to  the  superior  of  which  the  frasnum  lingua 
adheres,  to  the  middle  the  genio-hyo-glossi,  and  to  the  in- 
ferior the  genio-hyoidsei  muscles  ;  above  and  on  each  side 
Of  these  are  depressions  for  the  sublingual  glands,  and  at- 


DUBLIN    DISSECTOR.  459 

the  lower  border  are  two  depressions  for  the  digastric  mus- 
cles. The  sides  of  the  maxilla  have  a  direction  backwards 
and  outwards,  on  their  outer  surface  is  an  oblique  line  which 
passes  backwards  and  upwards  to  the  anterior  edge  of  the 
coronoid  process,  it  gives  attachment  before  to  the  platys- 
ma  and  depressor  anguli  oris,  and  behind  to  the  buccinator 
muscles  ;  internally  also  is  an  oblique  line,  parallel  to,  but 
more  prominent  than  the  external,  to  this  is  attached  the 
mylo-hyoid  muscle  anteriorly,  and  the  superior  constrictor 
of  the  pharynx  posteriorly ;  beneath  this  line  is  a  slight 
groove  which  contains  the  mylo-hyoid  nerve,  and  below 
this  an  oblong  depression  for  the  submaxillary  gland  ;  the 
lower  edge  or  base  of  the  jaw  is  rounded,  thick  before,  thin 
behind,  and  grooved  opposite  the  second  molar  tooth  for 
the  facial  artery ;  the  upper  or  alveolar  edge  is  broad  pos- 
teriorly and  bent  a  little  inwards  ;  it  has  usually  sixteen 
alveoli,  which,  as  in  the  upper  jaw,  vary  in  form  according 
to  that  of  the  teeth.  The  angle  of  the  jaw  is  more  or  less 
obtuse,  and  often  bent  a  little  outwards;  the  masseter  ad- 
heres to  it  externally,  the  internal  pterygoid  internally,  and 
ther  stylo-maxillary  ligament  to  the  border  of  it.  The  ra- 
mus  ascends  a  little  backwards,  is  thick  and  round  posteri- 
orly, and  is  enveloped  by  the  parotid  gland,  externally  it  is 
covered  by  the  masseter,  internally  it  presents  a  deep  groove 
which  leads  to  a  large  hole,  the  inferior  dental  or  maxillary; 
this  is  situated  near  the  centre  of  the  ramus,  and  is  pro- 
tected internally  by  a  prominent  spine  into  which  the  in- 
ternal lateral  ligament  is  inserted,  a  slight  groove  leads  from 
this  hole  to  the  mylo-hyoid  muscle ;  the  dental  hole  leads 
into  a  canal  which  traverses  the  side  of  the  bone  beneath 
the  alveoli,  with  each  of  which  it  communicates ;  it  con- 
tains the  dental  nerve  and  vessels ;  below  the  incisors  this 
canal  turns  back  a  little,  and  ends  at  the  mental  hole  ;  .his 
canal  is  nearer  the  inner  surface  of  the  jaw  behind,  arid 
the  outer  surface  before ;  the  ramus  ends  above  in  a  notch 
and  two  processes,  the  anterior  or  coronoid,  the  posterior 
Or  condyloid  ;  the  notch  is  traversed  by  the  masseter  nerve 
and  vessels.  The  coronoid  -process  is  triangular,  the  apex  is 
inclined  a  little  outwards,  it  is  embraced  by  the  insertion 
of  the  temporal  muscle.  The  condyle  is  an  oblong  convex 
process  supported  by  a  neck  which  is  most  depressed  an- 
teriorly, for  the  insertion  of  the  external  pterygoid  muscle  ; 
the  condyle  is  curved  forwards  and  most  convex  in  that  di- 
rection ;  it  is  directed  obliquely  backwards  and  inwards, 
so  that  its  internal  extremity  is  posterior,  it  is  also  higher 
than  the  external ;  its  posterior  surface  is  nearly  straight, 
and  almost  free  from  cartilage.  By  these  processes  the 
lower  maxilla  is  articulated  with  the  temporal  bones  ;  on 


460  DUBLIN    DISSECTOR. 

the  external  edge  of  each  is  a  tubercle  for  the  insertion  of 
the  external  lateral  ligament.  The  lower  jaw  in  the  young 
subject  always  consists  of  two  symmetrical  pieces,  each 
angle  is  very  obtuse,  and  the  condyles  are  directed  more 
upwards  than  in  the  adult. 

[In  many  of  the  inferior  animals  this  bone  consists  of  two  pieces 
during  life  ;  and  in  serpents  there  is  motion  at  the  symphysis ;  the 
angle  is  obtuse  in  children,  nearly  right  in  the  adult,  and  obtuse 
again  in  old  age :  fractures  of  this  bone  may  occur  in  the  body  or 
rami ;  and  portions  of  it  have  been  successfully  removed  for  osteo 
sarcoma. 

Muscles.  Fourteen  pair  are  attached  to  this  bone ;  eight  pair  arise 
from  it ;  the  levator  and  depressor  labii  inferioris,  depressor  anguli 
oris  and  buccinator  from  its  anterior  surface ;  the  mylo-hyoideus  and 
constrictor  pharyngis  superior  from  the  mylo-hyoid  ridge ;  and  the 
genio-hyo-glossus  and  genio-hyoideus  from  the  posterior  surface  of 
the  symphysis.  Six  pair  are  inserted  into  it ;  the  rnasseter  at  the  junc- 
tion of  the  body  and  ramus  ;  a  few  fibres  of  the  platysma  myoides ; 
the  digastric  into  the  digastric  fossa ;  the  temporal  into  the  coronoid 
process;  and  the  pterygoidei  internus  and  externus  into  the  internal 
surface  of  the  ramus  and  neck.] 

The  teeth  are  small,  hard  bones,  thirty-two  in  number  in 
the  adult,  sixteen  in  each  jaw ;  their  form  is  generally  co- 
nical, the  apex  in  the  aveoli ;  in  each  tooth  we  distinguish 
the  crown,  neck,  and  root ;  the  crown  is  external  to  the  al- 
veolus, it  has  no  periosteum,  but  is  covered  by  a  firm,  white, 
vitreous  substance,  named  enamel :  the  neck  is  surrounded 
by  the  gum,  and  the  root  is  firmly  held  in  the  alveolus  by  a 
mode  of  connexion  called  gomphosis.  The  teeth  are  di- 
vided into  three  classes,  the  incisores,  the  canini  and  the 
molares :  the  incisores  are  four  in  each  jaw,  the  crown  of 
these  is  sharp  and  wedge-shaped,  convex  before,  and  thick- 
ly covered  with  enamel;  those  in  the  upper  are  stronger 
than  those  in  the  lower  jaw  ;  the  former  are  broader,  their 
edge  is  like  a  chisel,  cut  off  posteriorly,  the  latter  are  more 
vertical,  their  anterior  surface  is  bevelled  off,  but  they  are 
not  so  sharp  as  those  in  the  upper  jaw,  their  roots  are  larg- 
er ;  the  canine  teeth  or  cuspidati  are  two  in  each  jaw,  the 
crown  is  conical,  a  little  blunt,  convex  before,  their  root  is 
single  but  very  long ;  the  grinders  or  molares  are  ten  in  each 
jaw,  the  crown  of  these  is  broad  and  irregular,  the  roots 
'are  rfiore  or  less  divided  ;  the  upper  grinders  are  stronger 
than  the  lower,  the  axis  of  the  former  is  directed  outwards, 
in  the  latter  it  is  vertical ;  the  two  first  molar  are  called 
bicuspidati,  and  are  smaller  than  the  canine  ;  they  have  only 
two  tubercles  on  the  crown  and  the  fang  is  single,  but  some- 
times it  is  double  ;  the  posterior  grinders  are  the  true  molar 
or  multieuspidati,  these  are  large,  the  crown  has  four  or  five 


DUBLIN    DISSECTOR.  461 

tubercles,  the  root  has  three  or  four  divisions,  and  each  is 
perforated  by  a  small  hole.  The  teeth  are  composed  of  a 
very  compact  bone  or  ivory,  less  brittle  than  the  enamel ; 
the  latter  only  covers  the  crown  as  far  as  the  neck ;  the 
ivory  has  no  cells  in  it,  its  fracture  is  silky :  in  addition  to 
the  component  parts  of  bone  it  also  contains  some  fluate 
of  lime  ;  it  possesses  the  power  of  resisting  the  action  of 
the  air  a  long  time  ;  the  enamel  is  very  white,  and  so  hard 
as  to  strike  tire  with  steel ;  it  is  composed  of  fibres  which 
are  perpendicular  to  the  surface  of  the  crown,  it  is  thicker 
where  the  teeth  are  exposed  to  much  friction,  it  does  not 
contain  any  vessels  or  nerves,  and  is  not  regenerated  when 
once  destroyed ;  each  root  is  perforated  with  a  small  hole 
which  leads  into  the  cavity  in  the  crown  ;  this  cavity  con- 
tains a  pulp  which  is  very  vascular  and  nervous. 

[In  the  infant  the  germs  of  fifty-two  teeth  exist ;  of  these  twenty 
make  their  appearance  during  the  period  of  lactation,  and  hence  they 
are  called  the  milk  teeth ;  they  are  also  called  nonpermanent  or  deci- 
duous ;  they  are  divided,  according  to  form  and  function,  into  inci- 
sores,  four  in  each  jaw,  cuspidati,  two  in  each  jaw,  and  molares,  four 
in  each  jaw ;  generally  these  teeth  begin  to  appear  about  the  sixth 
month,  and  are  complete  from  the  twenty-fourth  to  the  thirtieth 
month  ;  at  about  six  years  they  begin  to  give  way  to  the  permanent 
teeth,  which  are  usually  all  complete  about  the  twelfth  year,  except 
the  two  last  molar  of  each  jaw,  the  denies  sapientite,  which  make 
their  appearance  from  the  eighteenth  to  the  twentieth  year.  The 
time  at  which  the  different  teeth  appear,  however,  varies  much  in 
different  subjects  ;  sometimes  children  are  born  with  teeth,  and  some- 
times a  third  set  appears  in  extreme  old  age.  Supernumerary  teeth 
are  not  very  rare,  generally  but  one  or  two  in  number,  occasionally 
more ;  in  the  collection  of  Dr.  J.  K.  Rodgers,  there  is  an  inferior 
maxilla,  which  had  twenty  or  twenty-two  teeth.  Caries  is  the  most 
common  disease  of  the  teeth ;  the  tartar  which  accumulates  round 
the  teeth  is  looked  upon  as  a  secretion  from  the  gums.] 

The  bones  of  the  face  are  connected  by  sutures  in  the 
same  manner  as  those  of  the  cranium,  it  is  unnecessary  to 
describe  these  individually,  as  they  are  all  named  from  the 
particular  bones  they  unite.  The  facial  bones,  in  addition 
to  forming  the  general  outline  of  the  face,  also  bound  seve- 
ral regions,  namely,  the  nose,  orbits,  and  the  palate,  also 
the  temporal,  zygomatic,  and  spheno  or  pterygo-maxillary 
fossse.  The  bones  entering  into  the  nose,  have  been  already 
mentioned  in  the  description  of  the  organs  of  sense  :  on  the 
other  regions  we  shall  make  a  few  remarks. 

The  orbits  are  of  a  pyramidal  figure,  the  base  looking  out- 
wards and  forwards,  the  apex  backwards  and  inwards: 
seven  bones  enter  into  the  parietes  of  each,  the  frontal, 
sphenoid,  ethmoid,  lachrymal,  maxillary,  palate,  and  malar ; 
the  upper  wall  or  the  roof  of  each  orbit  is  formed  by  the 
39* 


462  DUBLIN    DISSECTOR. 

frontal  and  the  lesser  wing  of  the  sphenoid,  it  is  concave, 
and  presents  the  optic  hole  posteriorly  and  the  depressions 
for  the  lachrymal  gland  and  for  the  trochlea  anteriorly ; 
the  floor  is  nearly  plane  and  looks  outwards  and  down- 
wards, it  is  formed  of  the  malar,  maxillary,  and  palate 
bones,  the  infra-orbital  canal  extends  along  it :  the  exter- 
nal wall  is  formed  by  the  sphenoid  and  malar  bones,  and 
the  internal,  which  is  smooth  and  plane,  is  formed  by  the 
lachrymal,  ethmoid,  and  sphenoid  bones.  The  bones  which 
form  the  base  of  the  orbit  are  the  frontal,  malar  and  max- 
illary ;  the  foramina  in  the  base  of  the  orbit  are  four,  viz. 
the  supra-orbital,  the  infra-orbital,  the  malar,  and  the  nasal 
duct ;  within  the  orbit  are  five,  viz.  the  optic,  which  is  in 
the  upper,  inner  and  posterior  part,  the  foramen  lacerum 
superius  which  leads  from  the  apex  upwards  and  outwards, 
the  internal  orbital  holes  which  are  found  in  or  close  to  the 
suture  along  the  internal  wall,  and  the  spheno-maxillary 
fissure  or  the  inferior  lacerated  hole  which  leads  from  the 
back  of  the  orbit  forwards  and  outwards  along  the  floor, 
this  slit-like  opening  is  bounded  by  the  sphenoid,  palate, 
maxillary  and  malar  bones.  The  axes  of  the  two  orbits 
are  oblique  lines,  which,  if  produced  posteriorly,  would  de- 
cussate about  the  sella  turcica,  while  anteriorly  they  would 
diverge. 

The  palatine  region  is  composed  of  the  palate  plates  of 
the  superior  maxillary  and  of  the  palate  bones,  and  is 
bounded  by  the  alveolar  arch,  by  the  pterygoid  processes 
of  the  palate  bones  and  by  the  hamular  processes  of  the 
sphenoid;  to  its  posterior  edge  the  soft  palate  and  uvula 
are  attached  ;  anteriorly  it  presents  the  foramen  incisivum 
or  the  anterior  palatine  canal,  and  posteriorly  the  orifices 
of  the  two  posterior  palatine  canals. 

The  temporal  fossa  is  placed  on  the  side  of  the  cranium 
and  face ;  it  is  bounded  internally  by  the  frontal,  sphenoid, 
parietal  and  temporal  bones ;  its  extent  superiorly  is  defined 
by  the  semilunar  ridge  on  the  side  of  the  cranium,  which 
is  marked  on  the  frontal  and  parietal  bones,  anteriorly  by 
the  malar  bone,  posteriorly  by  the  pulley-like  root  of  the 
zygomatic  process,  and  inferiorly  and  externally  by  the 
zygomatic  arch  which  is  formed  by  the  processes  of  that 
name  from  the  temporal  and  malar  bones ;  this  a  -ch  is 
concave  above  and  internally,  convex  below  and  externally. 

The  zygomatic  fossa  is  continuous  with  the  lower  part  of 
the  last  described  region,  from  which  it  is  distinguished  by 
a  transverse  ridge  or  crest  upon  the  root  of  the  great  wing 
of  the  sphenoid  bone,  from  this  it  extends  to  the  tuberosity 
of  the  maxillary  bone,  and  is  bounded  externally  by  the 
ramus  of  the  lower  jaw. 


DUBLIN    DISSECTOR.  463 

The  pterygo-maxillary  fossa  is  a  very  narrow  space,  is  en- 
closed between  the  pterygoid  processes  behind,  the  tuber- 
osity  of  the  maxillary  bone  before,  and  bounded  internally 
by  the  nasal  lamella  of  the  palate  bone,  which  separates  it 
from  the  nose  ;  it  contains  the  spheno-palatine  ganglion 
and  the  internal  maxillary  artery.  It  is  immediately  below 
and  behind  the  orbit,  with  which  it  communicates  by  the 
spheno-maxillary  fissure,  it  also  communicates  with  the 
palate  by  the  posterior  palatine  canals,  with  the  nose  by 
the  spheno-palatine  hole,  with  the  face  by  the  infra-orbital 
canal,  and  it  also  opens  directly  into  the  temporal  and 
zygomatic  fossae ;  the  branches  of  the  second  division  of 
the  fifth  pair  of  nerves  pass  off  through  these  several  com- 
munications. 

THE   BONES   OF   THE   EXTREMITIES. 

The  extremities  are  two  superior,  and  two  inferior. 

The  inferior  extremity  is  divided  into  three  parts,  the  thigh, 
leg,  and  foot ;  the  latter  is  subdivided  into  the  tarsus,  meta- 
tarsus, and  toes :  the  thigh  has  one  bone,  the  femur ;  the 
leg  three,  the  patella,  tibia,  and  fibula ;  the  tarsus  seven, 
the  astragalus,  calcaneum,  cuboid,  scaphoid,  and  three 
cuneiform ;  the  metatarsus  five,  and  the  toes  fourteen  : 
thirty  bones  in  all,  [exclusive  of  the  two  sesamoid  bones 
of  the  great  toe.] 

The  femur  is  the  longest  bone  in  the  system,  it  consists 
of  the  body  or  shaft  and  two  extremities ;  the  body  is 
slightly  twisted,  thick  above,  very  broad  below,  contracted 
and  nearly  cylindrical  in  the  centre,  arched  and  smooth 
before  and  concave  behind,  with  a  sharp,  rough  ridge  down 
the  centre,  named  the  linea  aspera,  this  extends  along  the 
middle  third  of  the  bone,  parallel  to  its  axis,  and  divides 
above  and  below  into  two  ridges,  these  pass  superiorly  one 
to  each  trochanter,  that  to  the  inner  being  the  shorter  ;  and 
inferiorly  one  to  either  condyle ;  these  inferior  divisions 
separate  further,  and  enclose  a  flat  triangular  space,  the 
popliteal ;  this  line  is  very  prominent  about  the  centre,  and 
presents  two  lips  and  an  interstice,  for  the  attachment  of 
different  muscles :  the  anterior  convex  surface  of  the  fe- 
mur is  broader  towards  either  end  than  in  the  centre,  it  is  a 
little  concave  superiorly,  the  sides  are  slightly  flattened, 
and  the  external  is  somewhat  narrower  than  the  internal, 
particularly  above  ;  above  the  middle  of  the  linea  aspera 
one  or  two  holes  may  be  seen  to  enter  obliquely  upwards, 
these  transmit  the  nutritious  or  the  medullary  vessels  of  the 
bone ;  to  the  linea  aspera  in  the  middle  of  the  thigh,  the 
vastus  externus,  the  adductor  tendons,  and  the  vastus  inter- 
nus,  are  attached ;  to  its  superior  external  branch  which 


464  DUBLIN    DISSECTOR. 

leads  to  the  great  trochanter  and  is  very  long,  the  adductor 
rnagnus,  glutceus  maximus,  and  vastus  externus  are  attached ; 
the  internal  branch  is  short  and  not  very  distinct,  it  leads 
to  the  lesser  trochanter,  and  gives  attachment  to  the  adduc- 
tor brevis,  pectinseus,  vastus  internus,  and  some  fibres  of 
the  iliacus  internus ;  to  the  lower  and  external  branch  of 
the  linea  aspera,  the  vastus  externus  and  short  head  of  the 
biceps  are  attached,  and  to  the  lower  and  internal,  the  vas- 
tus internus  and  adductor  magnus  adhere ;  these  lines  con- 
tinue as  low  as  the  condyles,  the  internal  is  smooth  and 
nearly  obliterated  near  its  middle  for  the  passage  of  the 
crural  artery. 

The  upper  or  pelvic  extremity  of  the  femur  presents 
three  eminences,  the  head  for  articulation  with  the  coty- 
loid  cavity,  and  the  trochanters  for  the  insertion  of  muscles. 
The  head  is  of  a  globular  figure,  and  forms  a  considerable 
segment  of  a  sphere,  it  is  directed  upwards,  forwards,  and 
inwards;  a  little  below  its  centre,  there  is  a  rough  depres- 
sion for  the  insertion  of  the -round  or  articular  ligament; 
with  the  exception  of  this  depression  the  head  is  covered 
throughout  with  cartilage  ;  it  is  supported  by  an  elongated 
process,  the  neck,  which  forms  an  angle,  more  or  less  obtuse, 
with  the  shaft  of  the  bone,  the  direction  of  this  process  is 
upwards,  inwards,  and  a  little  forwards,  it  is  flattened  before 
and  behind,  thicker  at  the  shaft  than  at  the  head,  its  lower 
edge  is  longer  but  smaller  than  the  upper ;  a  rough  irregu- 
lar line  separates  the  head  from  the  neck,  beyond  which 
the  articular  cartilage  does  not  extend,  and  at  its  juncture 
to  the  shaft  two  rough  [intertrochanteric]  lines  extend  in- 
wards and  downwards,  from  the  great  to  the  lesser  trochan- 
ter, one  on  the  fore,  the  other  on  the  back  part  of  the  bone, 
into  these  the  capsular  ligament  is  inserted.  The  great 
trochanter  is  continuous  with  the  external  side  of  the  shaft, 
and  nearly  in  a  line  with  its  axis,  it  is  on  a  little  lower  level 
than  the  head,  it  is  thick,  rough  and  square,  externally  it  is 
broad  and  convex,  the  tendon  of  the  glutseus  maximus  moves 
over  this  surface  and  an  intervening  bursa,  a  prominent  ridge 
bounds  it  below,  to  this  some  fibres  of  the  vastus  externus  are 
attached,  internally  it  presents  a  pit  or  digital  cavity  which 
receives  the  tendons  of  the  external  rotators  of  the  limb, 
namely,  the  pyriform,  gemelli,  and  obturators ;  the  summit 
of  the  trochanter  is  thick  and  rough,  the  glutseus  medius  is 
inserted  into  it,  the  anterior  edge  is  broad,  and  gives  attach- 
ment to  the  glutseus  minimus,  into  the  posterior,  which  is 
round  and  thick  the  quadratus  femoris  is  inserted.  The 
lesser  trochanter  is  a  conical  projection  at  the  posterior  and 
inner  side  of  the  shaft,  and  is  considerably  below  the  great 
trochanter ;  it  looks  backwards  and  inwards,  the  tendons 


DUBLIN    DISSECTOR.  465 

of  the  psoas  and  iliac  muscles  are  inserted  into  it  behind 
its  apex,  a  bursa  is  connected  to  it  anteriorly.  The  inferior 
or  tibial  end  of  the  femur  is  very  large  and  broad,  and  divi- 
ded into  two  eminences  or  condyks  which  are  separated 
posteriorly  by  a  deep  [intercondyliac]  notch ;  the  condyks 
articulate  with  the  tibia  ;  the  external  is  larger,  and  projects 
more  forward  than  the  internal,  its  articulating  surface  is 
also  broader  and  ascends  higher,  externally  it  is  rough  and 
presents  a  tuberosity  which  gives  attachment  to  the  exter- 
nal lateral  ligament  of  the  knee  joint ;  this  is  less  promi- 
nent than  the  internal  tubercle  ;  beneath  this  tubercle  is  a 
groove  which  receives  the  tendon  of  the  poplitseus  muscle 
in  the  flexed  position  of  the  joint :  internally  this  condyle 
presents  a  rough  surface,  towards  the  posterior  part  of 
which  the  anterior  crucial  ligament  is  inserted,  it  is  very 
convex  behind,  flat  before,  and  broad  below.  The  internal 
condyle  is  narrower,  less  prominent  before  but  prolonged  more 
behind  ;  it  is  also  longer  than  the  external,  and  therefore 
descends  lower  when  the  femur  is  vertical,  but  both  are 
nearly  on  a  level  when  the  bone  is  in  its  ordinary  oblique 
direction  ;  on  its  inner  side  is  the  tubercle  for  the  attach- 
ment of  the  internal  lateral  ligament  of  the  knee  and  for 
the  adductor  tendon  ;  to  its  outer  side,  which  is  rough,  the 
posterior  crucial  ligament  adheres ;  both  condyles  are 
more  convex  behind  than  before,  they  are  separated  poste- 
riorly by  a  deep  uneven  notch,  which  lodges  the  crucial 
ligaments  and  is  deprived  of  articular  cartilage ;  anteriorly 
they  are  continued  into  each  other,  and  unite  in  a  pulley- 
like  surface  which  is  convex  from  above  downwards,  and 
concave  from  side  to  side,  higher  externally  than  internal- 
ly ;  this  trochlea  is  chiefly  formed  on  the  external  condyle, 
it  supports  the  patella:  the  femur  is  articulated  superiorly 
with  the  ilium,  inferiorly  with  the  tibia,  and  anteriorly  with 
the  patella;  like  all  long  bones  it  is  composed  of  compact 
tissue  in  the  centre  and  cellular  at  the  extremities,  the  com- 
pact has  a  fibrous  appearance,  the  whole  shaft  is  tra- 
versed by  a  distinct  medullary  canal,  which  is  crossed  by 
numerous  bony  Iamina3  ;  the  femur  is  developed  by  five 
points  of  ossification,  one  for  the  shaft,  one  for  the  tibial 
end,  one  for  the  head,  and  one  in  each  tronchanter. 

[This  bone  is  the  seat  of  various  fractures;  as  fracture  of  the  neck 
within  the  capsular  ligament,  fracturing  off  of  the  trochanter  major, 
fracture  below  the  trochanters,  fracture  at  almost  any  point  of  the 
shaft,  and  fracturing  off  of  one  or  the  other  condyle.  It  is  also  the 
seat  of  several  diseases  affecting  either  the  compact  tissue  of  the 
shaft,  or  the  spongy  tissue  of  the  extremities. 

Muscles.  Twenty. two  muscles  are  attached  to  this  bone  on  each 
side ;  seven  arise  from  it :  the  vasti  externus  and  internus,  and  cm- 


466  DUBLIN    DISSECTOR. 

reus  from  its  surfaces  and  linea  aspera ;  the  short  head  of  the  biceps 
flexor  cruris  from  the  external  lip  of  the  linea  aspera  below  its  mid. 
die  ;  the  gastrocnemius  from  both  condyles  posteriorly  ;  and  the  pop. 
liteus  and  plantaris  from  the  external  condyle :  fifteen  are  inserted 
into  it;  the  glutei  medius  and  minimus  into  the  trochanter  major ; 
the  pyriformis,  two  gemelli,  and  two  obturatores  into  the  digital 
fossa  ;  the  quadratus  femoris  into  the  posterior  intertrochanteric  line  ; 
the  psoas  magnus  and  iliacus  internus  into  the  trochanter  minor; 
the  pectineus  and  three  adductors  into  the  linea  aspera  by  its  internal 
lip;  and  the  glutens  maximus  into  the  superior  half  of  its  external 
lip.] 

The  bones  of  the  leg  are  the  patella,  tibia  and  fibula. 

The  patella  or  rotula  or  knee  cap  is  a  small  bone  in  front 
of  the  knee  joint,  of  a  triangular  figure,  the  base  above, 
the  apex  below,  its  anterior  surface  is  convex  and  covered 
by  skin,  a  bursa,  and  some  tendinous  fibres,  it  is  mark- 
ed by  several  longitudinal  lines,  and  presents  a  very  fibrous 
appearance  ;  the  posterior  surface  is  covered  with  cartilage 
and  divided  by  a  prominent  vertical  line  into  two  lateral 
portions,  of  these  the  external  is  larger  and  deeper  than  the 
internal ;  beneath  these  is  a  small  triangular  depressed 
surface  into  which  the  ligament  of  this  bone  is  insert- 
ed ;  the  upper  edge  is  round  and  cut  oft'  obliquely  back- 
wards and  downwards,  to  it  the  extensor  tendons  are 
attached ;  the  patella  is  of  a  cellular  structure,  and  cover- 
ed by  a  compact  lamina  which  is  very  dense,  and  tra- 
versed by  longitudinal  strice  ;  it  is  developed  from  a  single 
point  of  ossification,  and  remains  for  a  long  time  cartilagi- 
nous ;  .it  is  articulated  with  the  condyles  of  the  femur,  and 
connected  to  the  tibia  by  a  powerful  ligament ;  it  protects 
the  forepart  of  the  knee,  and  serves  as  a  medium  of  con- 
nexion between  the  extensor  tendons  and  the  leg. 

[This  bone  is  the  scat  of  three  fractures,  the  longitudinal,  trans- 
verse, and  stellated.  Four  muscles  are  inserted  into  this  bone,  the 
two  vasti,  the  rectus  femoris  and  crureus.J 

The  tibia,  next  to  the  femur,  is  the  longest  bone  in  the 
skeleton,  it  occupies  the  anterior  and  inner  part  of  the  leg, 
its  upper  extremity  is  thick  and  expanded  from  side  to  side, 
its  circumference  Is  somewhat  circular  or  oval,  convex  on 
the  front  and  sides,  but  slightly  grooved  behind  ;  on  either 
side  is  a  protuberance,  that  on  the  internal  is  the  more  pro- 
minent for  the  insertion  of  the  internal  lateral  ligament 
and  the  tendon  of  the  serni-membranosus  muscle ;  a  little 
behind  the  external  tuberosity  is  a  small  rounded  surface 
looking  downwards,  covered  with  cartilage  for  articulation 
with  the  head  of  the  fibula  ;  on  the  anterior  part  of  the 
head  is  a  convex  triangular  surface  looking  forwards  and 
downwards,  pierced  with  many  vascular  holes,  and  termi- 


DUBLIN    DISSECTOR.  467 

nating  in  a  tubercle,  to  the  upper  part  of  which  a  bursa 
adheres,  and  into  the  lower  the  ligamentum  patellae  is  in- 
serted. The  upper  or  femoral  surface  of  the  tibia  presents 
two  concave  or  articulating  surfaces  or  condyles  covered 
with  cartilage,  for  articulating  with  the  femur,  the  internal 
is  oval  and  the  deeper  of  the  two,  it  is  also  larger  from  be- 
fore backwards ;  the  external  is  nearly  circular,  very  super- 
ficial, and  looks  obliquely  downwards  and  outwards  ;  these 
are  separated  by  a  spine,  which  is  of  a  pyramidal  form, 
inclines  upwards  and  inwards,  and  is  surmounted  by  two 
tubercles ;  it  is  nearer  the  back  than  the  forepart  of  the 
bone  ;  a  large,  flat,  depressed  surface  lies  anterior  to  it,  and 
a  smaller  depression  behind  it ;  the  semilunar  cartilages 
and  the  crucial  ligaments  are  inserted  into  these ;  the  body 
of  the  tibia  is  triangular,  its  size  diminishes  from  its  head 
for  about  two-thirds  down,  it  then  increases  somewhat 
towards  its  lower  end ;  its  inner  side  is  convex  above  and 
a  little  concave  below,  it  is  directed  obliquely  forwards,  is 
covered  superiorly  by  the  tendinous  expansions  of  the  sar- 
torius,  gracilis,  and  semitendinosus,  but  the  remainder  of 
it  is  subcutaneous ;  the  external  side  appears  a  little  twisted, 
it  is  concave  above  to  support  the  tibialis  anticus  muscle, 
but  convex  below  to  support  the  tendon  of  that  muscle,  as 
also  those  of  the  extensors ;  its  posterior  surface,  which  is 
also  broader  above  than  below,  is  slightly  convex ;  it  pre- 
sents superiorly  a  prominent  line  passing  obliquely  down- 
wards and  outwards  for  the  insertion  of  the  popliteeus  and 
the  origin  of  the  solreus  and  the  deep  flexors ;  near  this  line 
is  the  opening  of  the  large  canal  that  leads  the  vessels  to 
the  medullary  membrane,  it  slants  obliquely  downwards 
and  forwards.  The  tibia  presents  three  edges,  one  is  ante- 
rior and  commences  from  the  tuberosity,  it  is  very  promi 
nent  about  the  middle,  but  less  so  above  and  rounded  below, 
this  line  is  subcutaneous,  it  is  twisted  like  the  tibia  itself, 
and  is  commonly  called  the  crest  or  the  shin,  the  inner  edge 
is  thick  and  round,  and  more  distinct  below  than  above, 
the  outer  edge  is  thin,  and  gives  attachment  to  the  interos- 
seous  ligament ;  it  is  less  distinct  and  bifurcated  below. 
The  lower  or  tarsal  end  of  the  tibia  is  somewhat  square, 
presents  an  anterior  convex  edge  covered  by  the  extensor 
tendons,  a  posterior  nearly  smooth  edge  traversed  by  a 
groove  for  the  tendon  of  the  flexor  pollicis  longus  ;  exter- 
nally is  a  concave  triangular  surface,  rough  above  for  liga- 
ments, and  smooth  and  cartilaginous  below  to  receive  the 
lower  end  of  the  fibula  ;  internally  the  tibia  ends  in  a  thick, 
flattened,  perpendicular  process,  the  internal  malleolus  or 
ankle  ;  it  is  convex  and  subcutaneous,  it  lies  anterior  to  the 
superior  internal  tuberosity  or  condyle,  on  account  of  the 


468  DUBLIN    DISSECTOR. 

twisting  of  the  bone ;  the  outer  side  of  this  process  is 
smooth  and  cartilaginous,  and  joined  at  right  angles  to  the 
cavity  at  the  lower  end  of  the  bone;  it  is  articulated  to  the 
side  of  the  astragalus,  its  anterior  edge  is  convex  and  gives 
attachment  to  ligaments,  its  posterior  edge  is  grooved  su- 
perficially for  the  tendons  of  the  tibialis  posticus  and  flexor 
communis;  the  extremity  of  this  process  is  broad  and 
descends  lower  before  than  behind,  it  gives  origin  to  the 
internal  lateral  ligament  of  the  ankle ;  the  lower  surface 
of  the  tibia  is  quadrilateral,  concave  from  before  back- 
wards, and  somewhat  convex  from  side  to  side,  being  tra- 
versed from  before  backwards  by  a  very  superficial  ridge 
or  prominence,  this  surface  is  broader  externally,  it  is 
bounded  internally  by  the  internal  malleolus,  and  exter- 
nally by  the  fibula ;  the  tibia  is  articulated  to  the  femur, 
the  fibula,  and  astragalus,  [and  to  the  patella  by  the  liga- 
mentum  patellae;]  its  ossification  commences  in  three 
points,  one  for  the  shaft,  and  one  for  each  extremity,  the 
tubercle  at  the  upper  end  of  the  crest,  and  the  malleolus 
are  sometimes  found  as  epiphyses. 

[This  bone  may  be  fractured  at  almost  any  point  of  its  shaft,  but 
is  most  liable  to  break  at  the  thinnest  part,  the  junction  of  the  mid. 
die  and  lower  thirds ;  one  of  the  condyles  may  be  fractured  off  ob- 
liquely, and  sometimes  the  malleolus  internus  is  broken  off. 

Muscles.  Ten  are  attached  to  this  bone ;  five  arise  from  it ;  the 
tibialis  anticus  and  extensor  longus  digitorum  from  its  anterior  sur- 
face ;  the  soleus,  tibialis  posticus,  and  flexor  longus  digitorum  from 
its  posterior  surface  :  five  are  inserted  into  it ;  the  sartorius,  gracilis, 
and  semitendinosus  into  the  upper  part  of  its  inner  face ;  the  semi- 
membranosus  and  popliteus  into  its  upper  and  back  part.] 

The  fibula  is  very  slender  and  nearly  as  long  as  the  tibia  ; 
it  is  placed  at  the  side  of  the  leg,  nearly  vertical,  its  lower 
end  inclined  a  little  forwards ;  the  superior  or  femoral  end 
is  small  and  circular,  and  presents  a  slight  cavity  forwards, 
upwards,  and  inwards,  to  articulate  with  the  tuberosity  on 
the  external  condyle  of  the  tibia,  behind  this  is  a  slight  py- 
ramidal projection,  [the  styloid  process,']  its  whole  circum- 
ference is  rough  for  the  insertion  of  ligaments  which 
attach  it  to  the  tibia,  also  for  the  external  lateral  ligament 
of  the  knee  joint,  and  for  the  tendon  of  the  biceps ;  below 
this  the  bone  is  round  and  slender  like  a  neck ;  the  body 
then  becomes  triangular ;  is  a  little  curved  backwards  and 
inwards  above,  but  is  twisted  forwards  below  ;  this  [the  in- 
ternal surface]  is  divided  into  two  portions  by  the  internal 
edge  into  which  the  interosseous  ligament  is  inserted,  the 
anterior  portion  gives  attachment  to  the  extensors,  and  the 
posterior,  which  is  larger,  is  grooved  for  the  tibialis  posti- 
cus, its  external  surface  is  covered  by  the  peronsei  muscles, 


DUBLIN    DISSECTOR.  469 

the  posterior  surface  gives  attachment  to  the  solaeus  above 
and  to  the  flexor  pollicis  below ;  in  this  surface  we  perceive 
the  orifice  of  the  vascular  canal  leading  downwards;  the 
internal  edge,  which  is  turned  a  little  forwards,  gives  at- 
tachment to  muscles  above  and  to  the  interosseous  ligament 
elow,  the  external  edge  is  turned  backwards,  and  gives 
ttachment  to  the  solasus,  flexor  pollicis,  and  peronaei  mus- 
lus ;  and  the  anterior  sharp  edge  to  the  extensor  digitorum 
nd  to  the  peronsei;   inferiorly  this  edge  turns  outwards 
nd  bifurcates,  enclosing  a  triangular  surface,   which  is 
ubcutaneous:   the  lower  or  larsal  end  is  larger  than  the 
ead,  it  is  elongated  into  a  long  oval  process,  the  external 
mlleolus  or  ankle  ;  this  is  larger,  more  prominent  and  pos- 
rior  to  the  inner  ankle,  it  is  convex  and  subcutaneous  ex- 
ernally,  internally  it  is  smooth  and  triangular,  a  little  con- 
ave  from  behind  forwards,  and  convex  in  the  perpendicu- 
ar  direction,  it  articulates  with  the  astragalus  ;  above  this 
3  a  triangular  rough  surface  to  articulate  with  the  tibia, 
nteriorly  this  process  is  rough  but  thin  for  the  origin  of 
gaments,  its  posterior  edge  is  broader  and  grooved  for  the 
eronteal  tendons,  internal  to  which  is  a  depression  for  the 
rigin  of  the  posterior  external  lateral   ligament  of  the 
nkle  joint ;   from  the  point  of  this  process  the  external 
ateral  ligament  arises;    the  fibula  is  articulated  at  both 
nds  to  the  tibia  and  below  to  the  astragalus. 

[This  bone  may  be  broken  either  alone  or  with  the  tibia,  being 
nost  liable  to  fracture  at  the  junction  of  the  middle  with  the  lower 
lird  ;  it  is  often  broken  in  conjunction  with  a  wrench  at  the  ankle 
oint.  The  malleolus  externus  may  be  broken  off. 

Muscles.  Nine  muscles  are  attached  to  this  bone  ;  eight  arise 
•cm  it ;  the  peronei  longus  and  brevis  from  its  external  surface ;  the 
xtensor  longus  digitorum,  extensor  pollicis  proprius,  and  peroneus 
ertius  in  front  of  the  interosseous  ligament ;  the  tibialis  posticus  be- 
ind  it,  all  from  the  internal  surface  :  the  soleus  and  flexor  pollicis 
ongus,  from  its  posterior  surface  ;  one  muscle  only  is  inserted  into 

the  biceps  flexor  cruris  at  its  styloid  process  and  head.] 

The  foot  is  divided  into  the  tarsus,  metatarsus,  and  toes, 
'he  bones  of  the  tarsus  are  seven,  astragalus,  calcaneum, 
lavicular,  cuboid,  and  three  cuneiform. 

The  astragalus  is  next  to  the  calcaneum  in  point  of  size, 
t  is  of  an  irregular  twisted  shape,  somewhat  cubical,  larger 
ibove  and  to  the  outside,  than  internally  or  posteriorly  ;  it 

situated  at  the  upper  and  middle  part  of  the  tarsus,  where 
t  is  wedged  between  the  two  malleoli,  its  superior  surface 
)resents  in  its  two  posterior  thirds  a  large  pulley-like  articu- 
ar  surface,  which  is  convex  from  behind  forwards,  and 
ioncave  transversely,  the  reverse  of  the  form  of  the  end  of 
he  tibia,  it  is  inclined  a  little  backwards,  is  broader  before 
40 


470  DUBLIN    DISSECTOR. 

than  behind,  and  more  prominent  externally  than  inter- 
nally ;  anterior  to  this  surface  is  a  rough  depression,  on  the 
neck  of  the  bone,  for  the  insertion  of  ligaments  ;  inferiorly, 
it  presents  two  articular  surfaces  for  the  os  calcis,  one 'is 
posterior  and  external,  broad  and  concave,  the  other  is  an- 
terior and  internal  and  convex ;  these  surfaces  are  sepa- 
rated by  a  deep  groove,  which  is  narrow  behind,  broad  be- 
fore, and  directed  forwards  and  outwards  ;  strong  ligaments 
pass  from  this  groove  to  the  os  calcis ;  the  posterior  surface 
of  the  astragalus  is  narrow  and  slightly  grooved  in  an  ob- 
lique direction  downwards  and  inwards,  for  the  tendon  of 
the  flexor  pollicis ;  it  also  presents  externally  a  pointed 
eminence  to  which  the  external  lateral  ligament  of  the 
ankle  joint  is  attached' ;  the  anterior  extremity  is  a  smooth 
round  head,  supported  by  a  sort  of  neck,  which  is  perforated 
by  many  small  holes  for  vessels,  it  is  directed  forwards,  in- 
wards, and  downwards,  and  is  articulated  with  the  navicu- 
lar  bone ;  the  external  side  presents  a  triangular,  smooth 
surface,  concave  from  above  downwards,  and  a  little  con- 
vex from  before  backwards,  it  is  articulated  with  the  fibula ; 
the  inner  side  is  rough  for  ligaments,  except  a  cartilaginous 
Surface  near  the  upper  part,  which  is  smaller  than  that  on 
the  outer  side,  and  broader  before  than  behind,  this  is  ar- 
ticulated with  the  internal  malleolus. 

The  calcaneum  or  os  calcis  is  the  largest  bone  in  the  tar- 
sus, at  the  lower  and  posterior  part  of  which  it  is  placed,  it 
is  elongated  posteriorly  into  a  process  called  the  heel,  its 
upper  surface  presents  two  articulating  surfaces  to  sup- 
port the  astragalus  ;  the  posterior  is  convex,  broad,  and  di- 
rected forwards  and  out'wards,  the  anterior  is  internal,  nar- 
row and  concave  ;  these  are  separated  by  a  deep,  rough, 
transverse  groove  into  which  strong  ligaments  are  inserted ; 
internal  to  this  the  bone  is  uneven,  and  projects  into  a  sort 
of  process,  into  which  the  internal  lateral  ligament  of  the 
ankle  joint  is  inserted  ;  the  inferior  surface  is  smaller  than 
the  superior,  and  is  nearly  flat,  it  presents  small  tubercles 
for  the  attachment  of  muscles  and  ligaments  ;  the  posterior 
extremity  is  slightly  convex,  smooth  above  and  covered  by 
a  bursa,  and  rough  below  for  the  insertion  of  the  tendo 
Achillis ;  the  anterior  extremity  is  smaller,  and  presents  an 
articular  surface  for  the  cuboid  bone,  which  is  concave 
from  above  downwards,  and  convex  from  side  to  side  ;  ex- 
ternally it  is  rather  flat,  being  marked  with  two  shallow 
grooves,  for  the  peronrcal  tendons,  a  spine  separates  these, 
into  this  the  external  lateral  ligament  of  the  ankle  joint  is 
inserted,  internally  it  is  broad  and  hollowed  out  into  an 
arch,  inider  which  the  flexor  tendons,  the  tibialis  posticus 
and  the  plantar  vessels  and  nerves  pass,  the  tendon  of  the 


DUBLIN    DISSECTOR.  471 

flexor  pollicis  runs  in  a  distinct  groove  ;  the  os  calcis  is  at- 
tached above  to  the  astragalus  and  before  to  the  cuboid. 

[The  groove  for  the  tendon  of  the  peroneus  longus  is  sometimes 
converted  into  a  large  osseous  pulley,  projecting  about  three  lines  from 
the  body  of  the  bone ;  of  this  I  have  two  specimens  from  the  same 
subject. 

Muscles.  Nine  are  attached. to  this  bone;  six  arise  from  it;  the 
extensor  digitorum  brevis  from  its  upper  and  outer  part;  abductor 
pollicis,  abductor  minimi  digiti,  flexor  brevis  digitorum,  flexor  acces. 
sorius,  and  flexor  brevis  pollicis  infcriorly  from  its  tubercles  and  mar- 
gins;  three  are  inserted  .into  it,  the  gastrocnemius,  soleus,  and  plan, 
taris  posteriorly.] 

The  navicular  or  scaphoid  bone  is  situated  about  the  middle 
of  the  tarsus  and  at  its  upper  and  internal  part ;  of  an  oval 
form,  its  long  axis  directed  downwards  and  inwards,  its 
posterior  surface. is  smooth  and  concave,  to  form  a  sort  of 
superficial  or  glenoid  cavity  for  the  head  of  the  astragalus, 
the  latter,  however,  is  much  larger  and  projects  inferiorly, 
in  which  direction  it  is  supported  by  the  strong  calceo-scap- 
hoid  ligament,  and  by  the  tendon  of  the  tibialis  posticus, 
which  here  generally  contains  a  sesamoid  bone  ;  the  ante- 
rior surface  is  convex,  and  divided  by  two  vertical  ridges 
into  three*  surfaces  for  the  three  cuneiform  bones  ;  the  cir- 
cumference is  irregular  for  the  attachment  of  ligaments,  in- 
ternally it  is  rather  smooth,  but  inferiorly  it  presents  a 
tubercle  into  which  the  tibialis  posticus  is  inserted  ;  on  its 
external  side  there  is  in  general  a  small,  Hat  articular  surface 
for  the  cuboid  bone ;  the  scaphoid  is  connected  to  five  bones, 
viz.  the  astragalus,  the  three  cuneiform,  and  the  cuboid. 

[Muscles.     One,  the  tibialis  posticus  is  inserted  into  this  bone.] 

The  cuboid  bone  is  situated  at  the  outer  and  anterior  part 
of  the  tarsus  external  to  the  navicular,  and  anterior  to  the 
calcaneum  ;  although  of  a  cubical  form,  it  is  yet  thicker 
and  longer  internally  than  externally,  its  upper  surface  is 
flat  and  rough  for  the  attachment  of  ligaments  and  muscles, 
the  lower  surface  is  irregular,  rough,  and  tubercular,  be- 
hind for  the  calceo-cuboid  ligament,  and  grooved  before  for 
the  tendon  of  the  peronoeus  longus,  its  posterior  surface  is 
smooth,  concave  transversely,  but  convex  from  above  down* 
wards,  this  slightly  pulley-like  surface  is  articulated  with 
the  calcaneum,  anteriorly  it  presents  two  articular  surfaces, 
the  internal  is  square  and  supports  the  fourth  met  a  tar  Sal 
bone,  the  external  is  triangular  and  supports  the  fifth  ;  the 
external  side  is  narrow,  the  internal  is  rough  posteriorly, 
but  presents  anteriorly  two  articulating  surfaces,  the  poste- 
rior for  the  scaphoid,  and  the  anterior  for  the  external  cu- 
neiform bone ;  the  cuboid  is  articulated  with  the  calcaneum, 


472  DUBLIN    DISSECTOR. 

the  scaphoid,  the  external  cuneiform,  and  the  two  external 
metatarsal  bones. 

[Muscles.  Several  of  the  small  muscles  of  the  foot,  to  some  extent 
arise  from  this  bone,  as  the  extensor  brevis  digitorurn  superiorly,  and 
the  flexor  brevis  pollicis,  adductor  pollicis,  and  flexor  brevis  minimi 
digiti  inferiorly.] 

The  cuneiform  bones :  these  three  wedge-shaped  bones  are 
situated  at  the  anterior  part  of  the  tarsus,  between  the 
scaphoid  and  the  three  internal  metatarsal  bones ;  the  first 
or  the  internal  is  the  largest  of  the  three,  its  base  is  below, 
and  its  long  axis  is  from  above  downwards,  it  is  articulated 
posteriorly  to  the  scaphoid  bone,  anteriorly  to  the  first  and 
externally  to  the  second  metatarsal  bone,  and  to  the  middle 
cuneiform,  inferiorly  its  presents  a  tubercle  for  the  inser- 
tion of  the  tibialis  anticus,  and  for  a  portion  of  the  tendon 
of  the  tibialis  posticus  ;  the  middle  cuneiform  is  the  smallest, 
and  is  wedged  in  between  the  two  others  ;  it  is  also  articu- 
lated behind  to  the  scaphoid  and  before  to  the  second  me- 
tatarsal bone ;  the  third  or  external  cuneiform  bone  is  situ- 
ated between  the  last  and  the  cuboid  bone,  it  is  articulated 
anteriorly  with  the  third  metatarsal  bone  :  posteriorly  with 
the  scaphoid,  internally  with  the  middle  cuneiform  and 
with  the  second  metatarsal  bone,  and  externally  with  the 
cuboid,  and  with  the  fourth  metatarsal  bone. 

[Muscles.  The  libialis  anticus  and  posticus  are  inserted;  the  first 
internally,  the  second  inferiorly  into  the  internal  cuneiform  bone  ;  and 
the  flexor  brevis  pollicis  arises  somewhat  from  the  others.] 

All  the  bones  of  the  tarsus  are  composed  of  a  soft,  spon- 
gy, vascular  tissue  covered  by  a  compact  but  thin  lamina  ; 
they  are  each  developed  from  one  point  of  ossification,  ex- 
cept the  calcaneum  and  the  astragalus,  which  commence 
each  in  two  points. 

The  metatarsal  bones  are  five  in  number,  the  first  or  inter- 
nal is  the  shortest  and  thickest,  convex  above,  concave  and 
sharp  below,  its  posterior  end  is  oval,  concave,  and  rests 
on  the  internal  cuneiform  bone,  the  anterior  end  round  and 
smooth,  supports  the  first  or  great  toe,  this  extremity  is 
grooved  below,  and  lodges  the  sesamoid  bones,  the  pero- 
na3us  longus  is  also  inserted  into  it ;  the  second  is  the  long- 
est of  the  metatarsal  bones,  its  tarsal  end  is  wedged  in  be- 
tween the  three  cuneiform  bones,  and  is  articulated  to  each 
of  them;  the  outer  side  of  its  base  is  also  joined  to  the  third 
metatarsal  bone,  its  anterior  extremity  or  head  is  round,  and 
supports  the  second  toe,  it  is  marked  internally  and  exter- 
nally by  the  depressions  for  the  lateral  ligaments,  a  groove 
separates  the  head  from  the  body  of  the  bone ;  the  third 
metatarsal  bone  is  a  little  shorter  than  the  second,  but  of  the 


DUBLIN    DISSECTOR.  473 

same  form  ;  its  base  rests  on  the  third  cuneiform  bone  ;  the 
fourth  metatarsal  bone  is  a  little  shorter,  it  rests  on  the  cu- 
boid bone,  and  the  inner  side  of  its  base  also  rests  against 
the  third  cuneiform  bone ;  the  fifth  is  the  shortest  except 
the  first,  it  rests  on  the  cuboid  bone  ;  the  heads  of  all  the 
metatarsal  bones  are  round  like  those  of  the  metacarpus, 
the  bases  flat  to  articulate  with  the  tarsus,  the  sides  of 
their  bases  are  also  flat  to  join  one  another ;  all  these  bones 
possess  a  similar  structure,  and  resemble  the  class  of  long 
bones. 

(  The  toes  are  five  in  number,  the  first  or  the  great  toe  has 
only  two  phalanges,  all  the  others  have  three  ;  there  are, 
therefore,  fourteen  phalanges  in  all ;  \hejirst  phalanges  are 
longest,  they  are  convex  above,  concave  below  ;  their  pos- 
terior end  is  larger  and  presents,  as  in  the  hand,  a  round 
concavity  for  the  head  of  the  metatarsal  bone ;  the  ante- 
rior end  is  convex  from  above  downwards,  and  concave 
from  side  to  side,  so  as  to  form  a  ginglymoid  joint  with  the 
second  phalanx.  The  second  phalanges  are  very  short,  the 
great  toe  has  none,  the  posterior  end  of  each  is  concave 
from  above  downwards,  but  convex  transversely,  being  di- 
vided by  a  vertical  ridge ;  the  anterior  extremity  is  smaller 
than  that  of  the  first  phalanx,  its  condyles  are  less  promi- 
nent. The  third  phalanges  are  all  very  small  except  that  of 
the  great  toe,  they  are  of  a  pyramidal  form,  and  support 
the  nails,  their  posterior  extremity  being  very  large  and 
similar  to  that  of  the  middle  phalanges,  their  anterior  end 
is  tubercular  and  attached  to  the  cellulo-vascular  texture 
at  the  extremity  of  each  ;  at  the  base  of  the  first  phalanx 
of  the  great  toe  there  are  in  general  two  sesamoid  bones  into 
which  the  small  muscles  of  this  toe  are  inserted,  frequently 
also  there  is  another  at  the  base  of  the  second  phalanx, 
sometimes  one  is  found  at  the  first  joint  of  the  second  toe, 
and  another  at  that,  of  the  fifth. 

[Muscles.  All  the  small  muscles  of  the  foot  are  inserted  into  the 
metatarsal  and  phalangeal  bones ;  besides  which  the  peroneus  longua 
is  inserted  into  the  metatarsal  bone  of  the  great  toe,  and  the  peronei 
brevis  and  tertius  into  that  of  the  fifth  toe  ;  the  flexor  longus  digito. 
rum,  flexor  longus  pollicis,  extensor  longus  digitorum,  and  extensor 
proprius  pollicis  are  inserted  superiorly  and  inferiorly  into  the  last 
phalangeal  bones.  The  bones  of  the  tarsus  an*  sometimes  fractured, 
but  only  by  great  violence ;  the  metatarsal  and  phalangeal  bones  are 
not  often  broken.] 

THE   SUPERIOR   EXTREMITIES. 

EACH  superior  or  thoracic  extremity  consists  of  the  shoulder, 
arm,  forearm,  wrist  and  hand;  the  whole  limb  comprises 
thirty-two  bones,  the  sesamoid  not  included  :  the  shoulder 
40* 


474  DUBLIN    DISSECTOR. 

is  composed  of  the  clavicle  and  scapula ;  the  arm  of  the 
humerus  ;  the  fore  arm  of  the  radius  and  ulna ;  the  wrist  of 
the  eight  small  carpal  bones;  the  hand  of  the  five  meto- 
carpal  and  fourteen  phalangeal  bones. 

The  clavicle  extends  from  the  summit  of  the  sternum  ob- 
liquely across  the  first  rib,  upwards,  backwards,  and  out- 
wards to  the  acromion  process  of  the  scapula,  it  is  curved 
somewhat  like  an  italic/,  particularly  in  the  male,  in  the 
female  it  is  straighter  and  longer ;  it  consists,  like  all  long 
bones,  of  two  extremities  and  a  body  or  shaft.  The  inter- 
nal  or  sternal  end  is  thick,  it  presents  a  triangular  articula- 
ting surface,  inclined  forwards  and  downwards,  convex 
from  above  downwards,  concave  from  before  backwards, 
large  above  and  before,  small  and  pointed  below  and  be- 
hind, the  circumference  is  rough  for  the  attachment  of  li- 
gaments. The  body  is  nearly  cylindrical  towards  the  ster- 
nal, but  flat  and  'expanded  towards  the  acromial  end, 
smooth  above  and  mostly  subcutaneous,  inferiorly  it  is 
rough  and  presents  about  an  inch  from  the  sternal  end  a 
ridge  or  process  for  the  rhomboid  or  costo-clavicular  liga- 
ment, external  to  this  is  a  groove  for  the  subclavian  muscle, 
in  this  also  is  a  foramen  for  the  nutritious  vessels,  and  near 
the  scapular  end  is  a  rough  ridge  leading  backwards  and 
outwards  for  the  attachment  of  the  coraco-clavicular  liga- 
ments ;  its  anterior  edge  is  convex  in  the  inner  half,  and 
gives  attachment  to  the  great  pectoral  muscle ;  the  outer 
half  is  concave,  to  it  the  deltoid  is  attached  ;  the  posterior 
is  smooth  and  concave  in  the  inner  half  towards  the  great 
vessels,  and  rough  and  convex  externally  for  the  attach- 
ment of  the  trapezius  muscle.  The  acromial  end  of  the  cla- 
vicle passes  over  the  coracoid  process  upwards  and  back- 
wards, is  flat  and  broad,  rough  above  and  below,  and  per- 
forated by  vessels ;  it  presents  at  its  termination  a  small  ar- 
ticulating surface  for  the  acromion  scapula? ;  this  surface 
is  oval  from  before  backwards,  and  cut  obliquely  from 
above  and  from  without  downwards  and  inwards,  its  aspect 
is  outwards,  forwards  and  downwards,  so  that  it  rather  rests 
on  or  over  the  articulating  surface  of  the  acromion  sea- 
puke,  its  circumference  is  rough  for  the  attachment  of  liga- 
ments. The  clavicle  serves  to  support  the  scapula,  and  to 
prevent  it  from  falling  too  much  forwards  or  inwards,  it 
thereby  allows  it  a  greater  freedom  of  motion,  it  also  serves 
as  a  fixed  point  for  certain  muscles,  and  it  protects  the  ves- 
sels and  nerves  of  the  upper  extremity ;  it  is  very  perfect 
in  the  foetus,  and  is  developed  from  a  single  point  of  ossi- 
fication ;  it  has  no  perfect  epiphysis,  although  in  the  young 
subject  there  is  an  osseous  crust  at  each  extremity,  which 
is  at  first  separable  from  the  rest  of  the  bone. 


DUBLIN    DISSECTOR.  475 

[This  bone  is  the  common  seat  of  fracture,  which  usually  occurs 
in  its  middle  third.  This  bone  has  been  successfully  removed,  both 
in  part  and  in  whole. 

Muscles.  Six  are  attached  to  this  bone  ;  four  arise  from  it ;  the 
sterno-rnastoid  and  sterno-hyoid  from  its  sternal  end ;  the  pectorali.s 
major  and  deltoid  from  its  anterior  border;  two  are  inserted  into  it, 
the  trapezius  posteriorly,  and  subclavius  inferiorly.] 

The  scapula  is  situated  at  the  upper,  lateral  and  posterior 
part  of  the  chest,  and  extends  from  the  second  to  the  sev- 
enth rib,  it  is  irregularly  flat  and  triangular,  it  presents  an 
internal  and  an  external  surface,  three  edges  and  three  an- 
gles. The  internal  or  anterior  surface  or  subscapular  fossa 
looks  towards  the  ribs,  is  slightly  concave,  and  divided  by 
three  or  four  prominent  lines  which  run  obliquely  from 
above  downwards,  and  from  without  inwards  into  several 
broad  grooves,  which  are  filled  by  the  fasciculi  of  the  sub- 
scapular  muscle,  the  aponeurosis  of  which  is  attached  to 
those  ridges ;  above  and  below  these  is  a  smooth  flat  sur- 
face to  which  the  serratus  magnus  is  attached.  The  ex- 
ternal or  posterior  surface  or  the  dorsum  is  divided  trans- 
versely into  two  unequal  parts  by  a  ridge  or  spine  which 
commences  about  the  upper  third  of  the  posterior  border 
of  the  scapula,  from  a  smooth,  polished,  flat,  triangular  sur- 
face, it  proceeds  forwards  and  becomes  more  elevated,  flat- 
tened above  and  below,  and  bounded  by  a  long,  irregular, 
undulated  margin,  which  is  rough  above  for  the  attach- 
ment of  the  trapezius,  and  below  for  that  of  the  deltoid 
muscle,  a  vascular  hole  is  observed  on  its  upper  and  under 
surface  :  this  spine  is  a  little  contracted  anteriorly  and  ex- 
ternally, and  terminates  in  an  eminence  named  the  acro- 
mion  process ;  this  surmounts  the  shoulder  joint,  about  an 
inch  above  it,  is  flattened  in  a  direction  contrary  to  that  of 
the  spine,  its  external  surface  looks  a  little  upwards  and 
backwards,  is  convex,  rather  rough  and  covered  by  the  in- 
teguments, its  inferior  or  internal  surface  is  smooth  and 
concave,  its  upper  edge  is  directed  backwards,  gives  at- 
tachment to  the  trapezius,  and  presents  near  its  termination 
a  small  and  nearly  horizontal,  oval,  articulating  surface 
for  the  clavicle,  the  aspect  of  this  surface  is  a  little  oblique 
upwards,  inwards  and  backwards ;  the  lower  edge  gives 
attachment  to  the  deltoid,  its  apex  is  rounded  for  the  inser- 
tion of  the  triangular,  or  coraco-acromial  ligament.  Above 
the  spine  is  the  supra-spinata  fossa,  which  is  wider  behind 
than  before,  this  is  filled  by  the  supra-spinous  muscle ;  the 
fossa  infra-spinata  is  larger,  is  convex  above  and  concavt 
and  grooved  inferiorly  ;  between  this  and  the  inferior  cost- 
is  a  raised  surface  extending  from  the  inferior  angle  to  the 
glenoid  cavity ;  this  surface  is  divided  into  two  by  an  ob- 


476  DUBLIN     DISSECTOR. 

lique  line,  the  posterior  portion  is  flat  and  somewhat  square, 
and  gives  attachment  to  the  teres  major  muscle,  the  ante- 
rior  to  the  teres  minor  ;  into  the  ridge  between  these  is  in- 
serted an  aponeurosis  common  to  these  two  muscles.  The 
superior  or  cervical  costa  or  border  of  the  scapula  is  the 
shortest  and  thinnest ;  at  its  forepart  is  a  [semilunar]  notch 
which  is  converted  into  a  hole  by  ligament  and  sometimes 
by  bone  ;  it  is  traversed  by  the  supra-scapular  nerve,  and 
sometimes  by  the  vessels  of  that  name,  to  this  costa,  the 
supra-spinatus,  subscapular  and  omo-hyoid  muscles  are 
attached.  From  the  anterior  part  of  this  border  in  front  of 
the  notch  arises  the  coracoid  process,  which  is  long  and  nar- 
row, and  directed  at  first  upwards  and  forwards  and  then 
downwards,  is  convex  and  rough  above  for  the  attachment 
of  the  conoid  and  trapezoid  ligaments,  smooth  and  concave 
below ;  it  overhangs  the  inner  and  upper  part  of  the  gle- 
noid  cavity,  the  pectoralis  minor  is  inserted  into  it  ante- 
riorly, the  biceps  and  coraco-brachialis  into  its  summit, 
and  the  triangular  ligament  into  its  external  border.  The 
base  of  the  scapula  or  the  posterior  or  vertebral  edge  is 
nearer  the  spine  above  than  below;  the  spinati  muscles 
adhere  to  its  outer  lip,  the  subscapular  to  its  inner,  and  the 
rhomboid  to  its  middle ;  about  one-fourth  from  its  upper 
extremity  is  a  blunt  projection  formed  by  the  smooth  trian- 
gular root  of  the  spine  ;  at  the  union  of  the  base  and  upper 
costa  is  the  superior  posterior  angle,  which  is  embraced  by 
the  levator  anguli  muscle.  The  anterior  or  inferior  or  ex- 
ternal or  axillary  costa  is  very  thick,  and  inclines  down- 
wards and  forwards,  at  its  junction  with  the  base  it  forms 
the  inferior  angle,  on  which  is  a  long  flat  surface  which 
gives  origin  to  the  teres  major,  and  to  a  few  fibres  of  the 
latissimus  dorsi  muscle ;  to  the  upper  part  of  it  the  long 
head  of  the  triceps  is  attached;  at  the  convergence  of  this 
and  of  the  superior  costa,  the  glenoid  cavity  and  the  neck 
of  the  scapula  are  situated.  The  neck  is  that  contracted 
portion,  which  gives  attachment  to  the  capsular  ligament, 
it  is  most  distinct  externally  and  inferiorly.  The  glenoid 
cavity  is  superficial,  oval,  broader  and  deeper  below,  cover- 
ed with  cartilage,  and  in  the  recent  subject  deepened  by 
the  fibrous  glenoid  ligament,  which  is  chiefly  derived  from 
the  long  tendon  of  the  biceps,  which  is  attached  to  the  up- 
per extremity  of  this  cavity ;  it  is  inclined  a  little  down- 
wards, outwards  and  forwards,  its  aspect  however  varies, 
as  the  scapula  is  made  to  turn  in  all  the  rotatory  motions 
of  the  arm.  The  scapula  is  composed  of  two  compact  la- 
minae and  an  intervening  cellular  tissue,  the  latter  prevails 
in  the  processes,  the  neck  and  the  inferior  angle ;  in  the 
middle  of  the  fossae  there  is  but  little  of  it,  and  the  compact 


DUBLIN    DISSECTOR.  477 

substance  is  there  thin  and  transparent.  The  scapula  is 
developed  by  several  points  of  ossification,  one  in  the  cen- 
tre of  the  body,  one  for  each  of  the  processes,  one  for  the 
inferior  angle  and  one  for  the  posterior  or  vertebral  edge. 

[This  bone  may  be  broken  in  its  body,  either  by  gun-shot  wounds 
or  blows  ;  the  acromion  process  may  be  broken  ;  and  fracture  of  the 
neck  may  occur,  and  be  confounded  with  fracture  of  the  neck  of  the 
os  brachii  or  dislocation  of  that  bone. 

Muscles.  Sixteen  are  attached  to  this  bone  ;  ten  arise  from  it ; 
the  supra  and  infra  spinatus,  arid  subscapularis  from  the  several  fos- 
sro  of  the  same  name  and  their  edges  ;  the  omo-hyoid  from  over  the 
semilunar  notch;  the  teres  major  and  minor,  and  long  head  of  the 
triceps  extensor  cubiti,  from  the  anterior  margin  :  the  deltoid  from  the 
lower  edge  of  the  spine  and  acromion ;  the  Jong  head  of  the  biceps 
flexor  from  the  apex  of  the  glenoid  cavity  and;its  short,  head,  and  the 
coraco-brachialis  from  the  coracoid  process  ;  six  are  inserted  into  it ; 
the  trape/ius  into  the  upper  edge  of  the  spine ;  the  levator  anguli 
scapulae  into  the  superior  angle.;  the  rhomboidei major  and  minor,  and 
serratus  magnus  anticus  into  the  base,  and  pectoraiis  minor  into  the 
coracoid  process.] 

The  os  humeri  is  attached  to  the  scapula  above  and  to 
the  radius  and  ulna  below  ;  it  is  the  longest  and  largest 
bone  in  the  upper  extremity,  it  presents  two  extremities 
and  a  body  or  shaft ;  the  upper  or  scapular  extremity  is  the 
larger,  it  consists  of  the  head,  neck  and  two  tubercles. 
The  head  is  semi-spherical,  inclined  upwards,  inwards  and 
backwards,  smooth  and  covered  with  cartilage  for  articulat- 
ing with  the  glenoid  cavity  of  the  scapula.  The?iec/c  is  the 
slightly  contracted  line  around  the  head,  it  is  rough  for  the 
attachment  of  the  capsular  ligament,  and  a  little  longer  be- 
low and  liefore  than  above  or  behind ;  the  axis  of  the  neck 
and  head  forms  an  obtuse  angle  with  that  of  the  shaft. 
The  tuberosities  are  two,  the  greater  or  lesser ;  thegrea/  or  ex- 
ternal is  also  posterior,  it  is  round,  and  presents  three  depres- 
sions ;  to  the  anterior  of  these  the  supra-spinous  muscle  is 
attached,  to  the  middle  the  infra-spinous  and  to  the  posterior 
the  teres  minor.  The  internal  or  lesser  tuberosity  is  also  ante- 
rior, it  is  more  prominent,  and  gives  insertion  to  the  subsca- 
pular  tendon  ;  between  these  tubercles  is  the  deep  groove 
for  the  long  tendon  of  the  biceps,  into  the  anterior  or  outer 
edge  of  which  the  tendon  of  the  great  pectoral  is  inserted, 
and  into  its  posterior  or  inner  those  of  the  teres  major  and  la- 
tissimus  dorsi,  this  groove  leads  downwards  and  inwards. 
The  body  or  shaft  of  the  humerus  is  thick  and  round  above, 
twisted  in  the  middle,  expanded  and  somewhat  triangular 
inferiorly  ;  its  posterior  surface  is  round  above  and  twisted 
a  little  inwards,  below  it  looks  outwards  and  is  flat  and 
broad  ;  this  surface  is  covered  by  and  gives  attachment  to 


478  DUBLIN    DISSECTOR. 

the  triceps  muscle,  a  small  vascular  foramen  may  be  ob- 
served about  the  centre.  The  anterior  surface  is  divided 
for  about  one-fourth  of  its  length  by  the  bicipital  groove 
into  two  unequal  portions,  the  internal  of  which  is  smooth, 
and  presents  near  its  centre  a  lineal  elevation  for  the  in- 
sertion of  the  coraco-brachialis,  in  the  lower  part  of  which 
is  an  oblique  vascular  foramen;  the  external  portion  is 
rough  above  for  the  insertion  of  the  deltoid  muscle,  a-nd  is 
grooved  obliquely  below  for  the  passage  of  the  musculo- 
spiral  nerve  and  artery ;  these  surfaces  are  separated  by 
two  prominent  lines,  one  is  external  and  anterior,  the  other 
is  internal  and  posterior,  these  lines  are  more  distinct  be- 
low than  above,  they  give  attachment  to  the  inter-muscular 
ligaments,  and  lead  down  to  either  condyle;  the  external 
is  interrupted  about  the  middle  by  the  musculo-spiral 
groove,  but  is  very  prominent  below,  curved  forwards,  and 
gives  attachment  to  the  brachialis  anticus,  the  supinators 
and  extensors,  the  triceps  and  the  external  intennuscular 
ligament ;  on  the  anterior  surface  of  the  humerus  there  is 
also  a  prominent  line  continued  from  the  anterior  edge  of 
the  bicipital  groove,  it  is  gradually  flattened  below,  and 
covered  .by  the  brachialis  anticus  muscle. 

The  lower  extremity  of  the  humeris  is  flattened,  elongated 
transversely,  and  twisted  a  little  forwards,  it  presents  in- 
ternally the  internal  condyle,  which  is  very  prominent  and 
turned  somewhat  backwards  ;  this  gives  attachment  to  the 
common  tendon  of  the  pronators  and  flexors,  and  to  the  in- 
ternal lateral  ligament  of  the  elbow  joint;  externally  is  the 
external  condyle,  not  so  prominent  as  the  internal,  and  situ- 
ated lower  down,  it  gives  attachment  to  the  external  lateral 
ligament,  and  to  the  supinator  and  extensor^  muscles. 
Between  and  below  these  condyles  is  an  articulating  sur- 
face turned  forwards  and  presenting  externally  a  small 
round  head  which  articulates  with  the  radius,  above  and  in- 
ternal to  which  is  a  slight  depression  corresponding  to  the 
margin  of  the  radius,  internal  to  this  is  a  sharp  semicircu- 
lar ridge  which  separates  the  radius  and  ulna,  and  next  to 
this  is  the  trochlea  for  articulation  with  the  ulna,  this  is  so 
much  below  the  level  of  the  small  head  and  of  the  outer 
portion  of  the  articular  surface,  as  to  give  the  whole  bone 
an  oblique  direction  outwards  when  its  lower  end  is  placed 
on  a  horizontal  plane  ;  at  the  anterior  extremity  of  this 
trochlea  is  a  small  depression  for  the  reception  of  the  co- 
ronoid  process  in  flexion  of  the  joint,  and  at  the  posterior 
is  a  large  fossa  which  lodges  the  olecranon  process  in  the 
extended  state  of  the  fore  arm. 

[The  anterior  and  posterior  semilunar  cavities  which  sometimes 


DUBLIN    DISSECTOR.  479 

communicate  through  a  perforation  in  the  bone ;  this  is  said  to  occur 
most  frequently  in  the  negro.] 

The  humerus,  like  the  femur,  is  compact  in  the  structure 
of  its  body,  and  cellular  in  that  of  its  extremities,  it  con- 
tains a  large  medullary  canal,  and  is  developed  from  eight 
points  of  ossification,  one  for  the  head,  one  for  each  tube- 
rosity,  one  for  the  shaft,  one  for  the  trochlea,  one  for  the 
small  head,  and  one  for  each  condyle. 

[This  bone  may  be  fractured  between  the  head  and  tuberosities, 
or  beneath  the  tuberosities,  or  at  any  point  of  its  shaft,  or  lastly  one 
of  the  condyles  may  be  broken  off. 

Muscles.  Twenty-four  are  attached  to  this  bone ;  fifteen  arise 
from  it;  the  middle  and  short  heads  of  the  triceps  extensor  and 
brachialis  anticus  from  the  shaft ;  the  supinatores  radii  longus  and 
brevis,  extensores  carpi  radialis  longior  and  brevior,  extensor  carpi 
ulnaris,  extensor  communis  digitorum,  extensor  minimi  digiti,  and 
anconeus  from  the  external  condyle  and  ridge  leading  to  it ;  the  pro. 
nator  radii  teres,  flexor  carpi  radialis,  flexor  carpi  ulnaris,  palmaris 
longus,  and  flexor  sublimis  digitonim  from  the  internal  condyle  and 
ridge  leading,  to  it.  Nine  are  inserted  into  it ;  the  subscapularis  into 
the  lesser  tuberosity  ;  the  supra  and  infra  spinati  and  teres  minor 
into  the  greater  tuberosity ;  the  pectoralis  major  into  the  anterior  lip 
of  the  bicipital  groove  ;  and  the  teres  major  and  latissimus  dorsi 
into  its  posterior  lip  ;  the  coraco-brachialis  and  deltoid  into  the  shaft.] 

The  ulna  is  situated  at  the  inner  side  of  the  fore  arm,  it  is 
longer  than  the  radius,  and  is  divided  into  the  body  and 
two  extremities;  the  upper  extremity  is  larger  than  the 
lower,  and  presents  two  processes  and  an  intervening  ca- 
vity. The  posterior  process,  or  the  olecranon,  is  the  highest 
part  of  the  bone,  its  superior  border  gives  attachment  to 
the  triceps  extensor ;  posteriorly  it  presents  a  smooth  tri- 
angular surface,  covered  hy  skin  and  by  a  bursa,  anteriorly 
it  is  concave  and  covered  with  cartilage..  The  coronoid  pro- 
cess is  anterior  and  inferior  to  the  preceding,  anteriorly  it 
gives  insertion  to  the  brachialis  anticus  muscle,  internally 
to  the  flexors  and  pronators,  and  to  the  internal  lateral  liga- 
ment, and  externally  it  is  hollowed  out  into  the  lesser  sig- 
moid  cavity,  which  receives  the  head  of  the  radius ;  this 
cavity  is  oval,  its  greatest  diameter  being  from  before 
backwards,  it  leads  superiorly  into  the  great  sigmoid  cavity, 
which  moves  on  the  trochlea  of  the  humerus  in  flexion  and 
extension  of  the  fore  arm ;  this  sigmoid  cavity  has  a  great 
resemblance  to  the  letter  C,  if  viewed  in  profile ;  its  pos- 
terior vertical  portion  is  larger  than  the  anterior  horizon- 
tal ;  it  is  divided  by  a  middle  ridge  into  two  lateral  por- 
tions, of  which  the  internal  is  the  larger;  these  are  each 
again  divided  by  a  transverse  furrow,  which  ends  in  a 
notch  at  either  margin,  this  surface  is  all  covered  with  car- 


480  DUBLIN    DISSECTOR. 

tilage,  except  the  furrow,  in  which  some  fatty  matter  is 
lodged.  The  body  of  the  ulna  is  divided  into  three  surfaces 
by  three  lines  ;  these  surfaces  are  larger  above  than  below  ; 
the  anterior  is  slightly  grooved  for  the  flexor  profundus, 
and  presents  superiorly  a  vascular  foramen,  directed  ob- 
liquely upwards;  the  internal  surface  is  broad  and  con- 
cave above,  and  covered  by  muscles,  below  it  is  round  and 
subcutaneous :  the  posterior  surface  is  irregular ;  it  is  di- 
vided into  two  portions  by  a  prominent  line  ;  of  these  the 
superior  and  internal  is  broad,  and  gives  attachment  to  the 
anconseus ;  the  inferior  and  outer  portion  is  long  and  nar- 
row, and  covered  by  the  extensors  of  the  thumb  ;  the  an- 
terior edge  is  round  and  gives  insertion  to  the  flexor  pro- 
fundus and  pronator  quadratus  ;  the  posterior  edge  is  very 
distinct  above,  and  gives  attachment  to  an  aponeurosis, 
common  to  the  flexor  profundus  and  flexor  and  extensor 
carpi  ulnaris ;  the  external  edge  is  sharp  for  the  three  su- 
perior fourths,  and  gives  attachment  to  the  interosseus  lig- 
ament. The  lower  or  carpal  end  of  the  ulna  is  small  and 
round,  and  presents  two  eminences ;  the  external  is  named 
the  head,  it  is  round  and  covered  with  cartilage,  and  is  re- 
ceived into  the  cavity  in  the  inner  border  of  the  radius, 
and  is  contiguous  inferiorly  with  the  nbro-cartilage  of  the 
wrist;  the  internal  eminence  or  the  styloid  process  is  more 
prominent,  and  on  a  level  with  the  posterior  surface  of  the 
bone ;  it  is  conical,  elongated  and  a  little  everted  ;  it  gives 
attachment  to  the  internal  lateral  ligament  of  the  wrist; 
these  processes  are  separated  posteriorly  by  a  groove  for 
the  tendon  of  the  extensor  carpi  ulnaris,  and  inferiorly  by 
a  depression  for  the  insertion  of  the  triangular  nbro-carti- 
lage. The  ulna  is  articulated  above  to  the  humerus  and 
radius,  and  below  to  the  radius,  and  inter-articular  carti- 
lage ;  it  is  developed  from  three  points  of  ossification,  one 
for  the  shaft,  and  one  for  each  extremity. 

[This  bone  may  be  broken  either  alone  or  with  the  radius  at  almost 
any  point  of  its  shaft ;  the  olecranoa  or  the  coronoid  process  may  be 
broken  off. 

Muscles.  Fourteen  are  attached  to  this  bone  ;  eleven  arise  from 
it;  the  flexor  carpi  ulnaris,  pronator  radii  teres,  flexor  sublimis  digi- 
torum,  flexor  profundus  digitorum,  and  pronator  radii  quadratus  an- 
teriorly ;  extensor  carpi  ulnaris,  extensor  ossis  metacarpi  pollicis,  ex- 
tensores  primi  and  secundi  inter-nodii  pollicis, extensor  indicis,  exten- 
sor digitorum  communis  posteriorly  ;  three  are  inserted  into  it ;  the 
triceps  extensor  into  the  olecranon  ;  the  brachialis  anticus  into  the 
coronoid  process,  and  the  anconeus  into  the  upper  and  back  part.] 

The  radius  is  shorter  than  the  ulna  by  the  length  of  the 
olecranon ;  it  is  situated  at  the  outer  and  anterior  part  of 
fore  arm,  is  larger  below  than  above,  is  curved  about  the 


DUBLIN    DISSECTOR.  481 

centre,  and  is  convex  outwards  and  backwards ;  it  is  di- 
vided into  the  body  and  two  extremities;  the  upper  or 
humeral  end  presents  a  head,  neck,  and  tubercle.  The  head 
is  a  circular  superficial  cavity,  its  surface  and  most  of  its 
circumference  covered  with  cartilage ;  the  former  to  arti- 
culate with  the  small  head  of  the  humerus,  and  the  latter 
with  the  sigmoid  cavity  of  the  ulna,  and  with  the  annular 
or  coronary  ligament ;  the  internal  or  ulnar  portion  of  the 
circumference  is  broader  than  the  external.  The  neck  is 
about  an  inch  long,  it  descends  obliquely  outwards,  it  is 
contracted  and  circular;  at  its  lower  extremity  is  the  tul-.ir- 
de,  this  process  is  directed  backwards  and  inwards,  into 
its  external  rough  surface  the  tendon  of  the  biceps  is  in- 
serted; anteriorly  it  is  smooth,  and  covered  by  a  bursa. 
The  body  or  shaft  of  the  radius  is  somewhat  triangular,  and 
presents  three  surfaces,  separated  by  three  margins  or  an- 
gles ;  the  anterior  surface  is  broad  below  and  covered  by 
the  pronator  quadratus,  narrow  above  where  it  gives  at- 
tachment to  the  flexor  pollicis ;  about  one-third  from  the 
head  is  the  orifice  of  the  vascular  canal,  slanting  obliquely 
upwards;  the  posterior  surface  is  convex  above  and  co- 
vered by  the  supinator  brevis,  concave  in  the  middle  for 
the  extensors  of  the  thumb,  and  convex  below  ;  the  exter- 
nal surface  is  round  and  convex,  and  presents  near  the 
centre  a  rough  surface  for  the  insertion  of  the  pronator 
teres  ;  of  the  angles  or  edges  the  inner  is  most  distinct ;  it 
is  sharp,  and  gives  attachment  to  the  interosseous  ligament. 
The  lower  or  carpal  end  of  the  radius  is  square,  its  anterior 
prominent  edge  gives  attachment  to  the  anterior  carpal 
ligament ,  posteriorly  it  presents  three  grooves  for  the  ex- 
tensor tendons  ;  one  nearly  in  the  middle  line,  narrow  and 
obliq-  ,e,  lodges  the  tendon  of  the  extensor  secundi  inter- 
nodii  pollicis,  the  second  is  at  the  ulnar  side  of  this,  is 
broad,  and  transmits  the  tendons  of  the  extensor  communis 
and  indicator,  and  the  third,  which  is  to  the  radial  side  of 
the  first,  is  divided  into  two  for  the  tendons  of  the  extensor 
carpi  radialis,  longus  and  brevis ;  along  the  external  bor- 
der of  this  bone,  is  another  groove  leaning  downwards  and 
forwards,  and  divided  into  two  for  the  extensor  ossis  meta- 
carpi  and  primi  internodii  pollicis ;  the  border  between 
these  two  last  grooves  is  prolonged  down  into  the  styloid 
process,  from  which  the  external  lateral  ligament  of  the 
wrist  arises ;  on  the  internal  border  is  an  oblong  smooth 
cavity,  to  receive  the  lower  end  of  the  ulna;  inferiorly  the 
radius  presents  an  articular  surface,  divided  by  a  line  from 
before  backwards,  into  two  unequal  portions ;  the  external 
is  large  and  triangular,  and  meets  the  scaphoid  bone ;  the 
internal  is  smaller,  somewhat  square,  and  meets  the  lunar 
41 


482  DUBLIN    DISSECTOR. 

bone.    The  radius,  like  other  long  bones,  is  of  a  cellula 
structure  at  each  extremity  and  compact  in  the  centre, 
where  it  also  contains  a  medullary  canal,  which  is  larger 
above  than  below  ;  it  is  developed  from  three  points  of  os- 
sification, one  for  the  shaft  and  one  for  each  extremity. 

[Fractures  of  this  bone,  alone  or  with  the  ulna  may  occur  at 
any  point  of  the  shaft ;  more  frequently  both  bones  are  broken  be- 
low the  middle ;  fracture  of  the  neck  of  the  radius  is  very  rare, 
and  when  occurring,  unites  by  fibro-ligamentous  substance.  I  have 
a  specimen  of  this  fracture  and  mode  of  union. 

Muscles.  Nine  are  attached  to  this  bone  ;  four  arise  from  it ; 
flexor  sublimis  digitorum,  flexor  longus  pollicis  from  its  anterior  sur- 
face ;  extensor  ossis  metacarpi  pollicis,  and  extensor  primi  inter-nodii 
posteriorly ;  five  are  inserted  into  it ;  the  biceps  flexor  into  the  bici- 
pital  protuberance  ;  supinator  brevis  and  pronator  teres  into  the  mid. 
die  of  the  outer  surface,  pronator  quadratus  into  the  lower  part  of  its 
anterior  edge,  and  the  supinator  longus  into  the  outer  surface  low 
down.] 

The  hand  consists  of  the  carpus,  metacarpus,  and  fin- 
gers. 

The  carpus  is  composed  of  eight  bones,  arranged  in  two 
rows ;  the  first  row  consists  of  the  scapoid,  lunar,  cuneiform 
and  pisiform  ;  the  second  of  the  trapezium,  trapezoid,  mag- 
num and  unciform ;  enumerating  them  from  the  radial  to 
the  ulnar  side,  or  from  without  inwards. 

The  scaphoid  or  navicular  is  the  largest  in  the  upper  row, 
at  the  radial  or  outer  side  of  which  it  is  situated ;  it  presents 
four  articular  surfaces ;  it  is  elongated  and  convex  on  the 
upper  or  radial  surface,  adapted  to  the  external  depression 
on  the  end  of  the  radius;  the  inferior  surface,  directed  a 
little  outwards  and  backwards,  is  triangular,  smooth  and 
convex,  to  articulate  with  the  trapezium  and  trapezoides; 
into  the  posterior  narrow  surface,  ligaments  are  inserted ; 
to  the  external  or  radial  side,  the  external  lateral  ligament 
is  attached ;  the  inner  or  ulnar  side  presents  two  smooth 
articulating  surfaces;  one  superior,  narrow,  to  articulate 
with  the  lunar  bone  ;  the  other  inferior,  large  and  concave, 
to  articulate  with  the  head  of  the  magnum :  it  thus  meets 
five  bones. 

[Muscles.  Three  arise  from  this  bone,  the  abductor  pollicis,  oppo- 
nens  pollicis,  and  flexor  pollicis  brevis.] 

The  lunar  or  semicircular  bone  is  smaller  than  the  scap- 
hoid;  it  presents  four  articulating  surfaces;  smooth  and 
convex  above  to  meet  the  radius,  concave  below  to  articu- 
late with  the  magnum  and  unciform :  its  ulnar  side  is  flat 
to  meet  the  cuneiform,  and  its  external  to  meet  the  scap- 
hoid ;  its  anterior  surface  is  larger  than  its  posterior  and 


DUBLIN    DISSECTOR.  483 

it  projects  a  little  into  the  palmar  arch :  it  is  articulated  to 
five  bones. 

The  cuneiform,  or  pyramidal  lone.  The  base  of  this  wedge- 
shaped  bone  looks  outwards  and  articulates  with  the  lunar, 
the  apex  is  inwards;  it  is  convex  and  smooth  above  to 
meet  the  carpal  fibro-cartilage  ;  concave  and  smooth  below 
to  articulate  with  the  unciform  bone  ;  rough  posteriorly 
and  internally  for  ligaments ;  anteriorly  it  presents  a  flat 
circular  cartilaginous  surface  for  the  pisiform  bone;  it  is 
articulated  to  three  bones  and  to  the  fibro-cartilage. 

The  pisiform  bone.  This  small  pea-shaped  bone  is  the 
smallest  in  the  carpus,  at  the  upper  and  inner  part  of  which 
it  is  placed ;  it  is  also  on  a  plane  anterior  to  the  first  row ; 
it  is  articulated  to  the  cuneiform  bone  by  a  small  circular 
surface ;  its  circumference  is  rough  for  the  attachment  of 
ligaments  ;  the  flexor  carpi  ulnaris  is  inserted  into  it  above, 
and  the  abductor  minimi  digiti  [arises  from  it]  below. 

The  trapezium  is  the  most  external  of  the  second  row  of 
the  carpus ;  it  is  concave  above  to  meet  the  scaphoid,  below 
it  is  convex  from  behind  forwards  and  concave  transverse- 
ly, to  support  the  metacarpal  bone  of  the  thumb  by  a  pul- 
ley-like surface;  anteriorly  it  is  marked  with  a  groove  for 
the  tendon  of  the  flexor  carpi  radialis;  internally  it  is 
articulated  to  the  trapezoid,  and  beneath  this  by  a  small 
surface  to  the  second  metacarpal  bone:  it  joins  four 
bones. 

[Muscles.  Three  are  attached  to  this  bone  ;  two  arise  from  it, 
the  abductor  pollicis  and  flexor  pollicis  brevis  ;  and  one  is  inserted 
into  it,  the  extensor  ossis  metacarpi  pollicis  by  one  of  its  tendons.] 

The  trapezoid  is  of  a  very  irregular  shape,  and  smaller 
than  the  trapezium ;  above  it  is  smooth  and  concave  t«> 
meet  the  scaphoid,  externally  it  articulates  with  the  trape- 
zium, internally  with  the  rnagnum,  and  inferiorly  with  the 
second  metacarpal  bone :  it  joins  four  bones. 

The  os  magnum  is  the  largest  of  the  carpal  bones ;  it 
presents  superiorly  a  round  and  hemispherical  head,  which 
is  received  into  the  socket  formed  by  the  scaphoid  and  lu- 
nar bones ;  this  head  is  supported  by  a  contracted  neck, 
its  greatest  convexity  is  turned  backwards  und  outwards ; 
the  inferior  surface  of  the  magnum  is  divided  into  three 
articulating  surfaces ;  these  support  the  second,  third,  and 
fourth  metacarpal  bones ;  that  for  the  the  third  is  the  lar- 
gest, and  for  the  fourth  the  smallest ;  its  posterior  surface 
is  broad  and  convex  below,  and  a  little  concave  above ; 
externally  it  joins  the  trapezoid,  and  internally  the  unci- 
form ;  both  anteriorly  and  posteriorly  it  gives  attachment 
to  the  ligaments ;  it  articulates  with  seven  bones. 


4#4  DUBLIN    DISSECTOR. 

[Muscles.  One  head  of  the  flexor  pollicis  biu/is  arises  from  this 
bone.] 

The  unciform  bone  is  next  in  size  to  the  os  magnum  ;  it  is 
situated  at  the  lower  and  inner  part  of  the  carpus,  is  rather 
wedge-shaped,  the  base  below,  articulated  with  the  fourth 
and  fifth  metacarpal  bones ;  its  upper  surface  is  narrow, 
and  meets  the  semilunar  bone ;  its  external  side  joins  the 
magnum,  its  internal  the  cuneiform ;  its  posterior  surface 
is  rough  for  ligaments ;  from  its  anterior  projects  a  small 
hooked  process,  curved  outwards  for  the  attachment  of  the 
annular  ligament  and  some  of  the  muscles  of  the  little  finger. 

[Muscles.  Two  arise  from  this  bone,  the  flexor  brevis  minimi  di- 
giti  and  adductor  minimi  digitL] 

All  the  bones  of  the  carpus,  like  those  of  the  tarsus,  are 
composed  of  a  loose  spongy  vascular  tissue,  invested  by  a 
thin  compact  lamina;  they  are  developed  each  from  a 
single  point  of  ossification,  except  the  unciform,  which  has 
two  ;  the  pisiform  is  the  latest  to  ossify. 

The  metacarpal  bones  belong  to  the  class  of  long  bones ; 
they  are  five  in  number,  are  placed  nearly  parallel  to  each 
other,  except  the  first  or  that  of  the  thumb,  which  is  on  a 
plane  anterior  to  the  others ;  the  first  is  thick  and  short, 
the  third  is  the  longest.  They  are  all  concave  on  the  pal- 
mar surface,  convex  on  the  dorsal,  and  large  at  each  ex- 
tremity ;  the  posterior  end  is  of  an  irregular  figure  ;  the  an- 
terior presents  a  round  head  ;  the  palmar  surface  of  each  is 
narrow,  and  presents  a  median  prominent  line  ;  the  posteri- 
or surface  of  the  first  is  convex,  but  on  the  second,  third, 
and  fourth,  it  presents  a  prominent  longitudinal  line,  which 
bifurcates  and  forms  the  sides  of  a  flat  triangular  surface, 
extending  for  near  two-thirds  of  their  length;  into  their 
edges  the  interossei  muscles  are  inserted ;  the  dorsal  sur- 
face of  the  fifth  is  divided  by  an  oblique  line  diagonally, 
the  outer  portion  is  concave,  and  lodges  the  fourth  interos- 
seous  muscle,  the  inner  convex  and  broad,  and  covered  by 
the  extensor  tendon  of  the  little  finger. 

The  carpal  end  or  base  of  the  first  is  -concave  from  be- 
fore backwards,  and  convex  transversely,  to  articulate  with 
the  trapezium  ;  the  base  of  the  second  is  concave,  and  arti- 
culates with  the  trapezoides,  and  presents  also  externally  a 
small  smooth  surface  for  the  trapezium,  and  internally  two 
smooth  surfaces,  one  for  the  magnum,  the  other  for  the  base 
of  the  third  metacarpal;  the  base  of  the  third  is  nearly 
plane,  and  rests  on  the  magnum,  and  presents  on  either 
side  articulating  surfaces  for  the  contiguous  metacarpal 
bones ;  the  base  of  the  fourth  presents  two  articulating  sur- 
faces, one  for  the  magnum  and  one  for  the  lioeiform ;  on 


DUBLIN    DISSECTr  485 

the  radial  side  two,  and  on  the  ulnar  side  one  articulating 
surface,  for  the  adjacent  metacarpal  bones;  the  base  of  the 
fifth  presents  a  concave  surface,  directed  outwards  to  arti- 
culate with  the  unciform  ;  its  radial  side  articulates  with 
»he  base  of  the  fourth  metacarpal  bone.  The  anterior,  or 
digital  ends  of  all  the  metacarpal  bones  ate  convex,  their 
smooth  surfaces  are  broader  and  extend  further  on  the 
palmar  than  on  the  dorsal  surfaces  of  each  ;  they  are  arti- 
culated with  the  bases  of  the  first  phalanges. 

The  fingers  are  composed  each  of  three  phalanges,  ex- 
cept the  thumb,  which  has  only  two ;  there  are  therefore 
fourteen  phalanges  in  all  4  the  JjrsZ,  or  those  next  the  meta- 
carpus, are  the  largest,  the  third  are  the  smallest,  the  second 
or  middle  are  of  an  intermediate  size.  The  metacarpal  or 
the  first  phalanges  are  five  in  number ;  the  base  or  poste- 
rior end  of  each  presents  a  cavity  transversely  oval  for  the 
head  of  the  metacarpal  bone ;  the  anterior  extremity  of  each 
presents  two  small  condyles,  separated  by  a  groove  ;  these 
are  prolonged  anteriorly,  and  articulate  with  the  second  or 
middle  phalanx ;  the  anterior  surface  of  each  is  arched 
from  before  backwards,  hollowed  from  side  to  side,  to  lodge 
the  flexor  tendon,  the  sheath  of  which  is  attached  to  its  late- 
ral edges ;  the  posterior  surface  is  convex  and  arched.  The 
second  or  middle  phalanges  are  four  in  number,  they  are 
smaller  than  the  first. ;  the  base  of  each  presents  two  small 
cavities  and  a  middle  ridge,  or  a  sort  of  pulley-like  surface 
to  articulate  with  the  first,  with  which  it  forms  a  gingly- 
moid  joint;  about  the  centre  of  their  anterior  surface  is  a 
rough  depression  for  the  insertion  of  the  teadon  of  the  flexor 
sublimis  ;  the  anterior  or  digital  extremity  of  each  resem- 
bles the  anterior  end  of  the  first  phalanx,  and  is  convex 
from  before  backwards,  and  con-cave  from  side  to  side  ;  the 
two  articulating  condyles  being  prolonged  on  the  palmar 
further  than  on  the  dorsal  surface,  so  as  to  increase  the  ex- 
tent of  flexion  ;  the  thumb  wants  this  second  phalanx.  The 
third  or  last  or  ungual  phalanges  are  five  in  number,  they 
are  the  smallest  and  somewhat  of  a  pyramidal  form,  the 
base  articulates  with  the  second  phalanx,  and  presents  a 
pulley-like  surface*  having  two  small  cavities  and  a  middle 
ridge,  such  as  the  base  of  the  second  phalanx  ;  their  pos- 
terior surface,  convex,  supports  the  nail,  their  anterior  is 
rough  and  irregularly  concave,  for  the  attachment  of  the 
flexor  tendon  and  ligaments  ;  its  anterior  extremity  or  apex 
is  irregularly  tuberoulated  to  support  the  extremity  of  the 
finger.  The  phalanges  in  structure  resemble  metacarpal 
bones  ;  the  last  or  the  u.ngual  are  more  cellular,  and  have 
no  medullary  canal ;  they  are  developed  each  from  tw© 
points  of  ossification,  one  for  the  shaft,  and  one  for  the  an 

41* 


486  DUBLIN    DISSECTOR. 

terior  extremity ;  the  posterior  end  is  continued  from  the 
shaft. 

[Muscles,  All  the  small  mnscles  of  the  hand,  except  the  palmaris 
brevis,  are  inserted  into  the  metacarpal  and  phalangeal  bones  ;  be. 
sides  which  the  extensor  ossis  metacarpi  polhcis  is  inserted  by  one 
of  its  tendons  into  the  metacarpal  bone  of  the  thumb;  the  extensor 
carpi  radtalis  longus,  and  flexor  carpi  radialis  into  that  of  the  index 
finger  ;  the  extensor  carpi  radialis  brevis  into  that  of  the  middle  fin- 
ger ;  extensor  carpi  ulnaris,  and  flexor  carpi  ulnaris  slightly  into  that : 
of  the  little  finger,  the  flexor  digitorum  sublimis  into  the  second  pha- 
langes ;  the  flexor  digitorum  profundus,  and  flexor  longus  pollicis 
into  the  last  phalanges  ;  the  extensor  digitorum  coiwmunis  into  the 
second  and  third  phalanges  of  the  four  fingers  ;  the  extensor  indicis 
into  those  of  the  index  finger;  the  extensor  digiti  minimi  into  those 
of  the  little  finger  ;  and  the  extensor  primi  internodii,  and  extensor  se- 
cundi  internodii  pollicis  into  the  first  and  last  phalanges  of  the  thumb. 
The  carpal  bones  are  not  often  broken,  it  requiring  great  violence  to 
fracture  them  ;  the  metacarpal  and  phalangeal  bones  are  more  fre- 
quently broken  than  those  of  the  feet,  from  being  more  exposed ;  in 
cases  of  supernumerary  fingers  and  toes  we  find  additional  phalan- 
geal bones,  and  sometimes  a  supernumerary  metacarpal  or  tarsal 
bone;  but  naore  cotmmonly  one  of  these  seems  to  spread  or  bifurcate, 
so  as  to  sustain  two  toes ;  this  malformation  is  often  hereditary.] 

On  the  fore  part  of  the  articulation  between  the  meta- 
carpal bone  and  the  first  phalanx  of  the  thumb  there  are 
generally  two  sesamoid  bones,  and  sometimes  one  in  the  cor- 
responding joint  of  the  index  finger  ;  these  bones,  like  those 
in  the  foot,  as  well  as  in  other  situations,  where  they  are 
occasionally  found,  as  behind  the  condyles  of  the  femur,  in 
the  heads  of  the  gastrocnemii  muscles,  &e.  do  not  properly 
belong  to  the  osseous  system,  they  are  rather  accessories 
to  the  tendons  of  muscles ;  they  are  found  in  the  limbs 
only,  and  generally  in  the  direction  of  flexion.  They  are 
developed  from  cartilage,  which  is  deposited  in  tendinous 
or  ligamentous  structure,  and  which  is  very  slow  to  ossify  ; 
the  patella  has  some  resemblance  to  bones  of  this  class,  it 
is,  however,  more  perfect,  and  is  placed  on  the  aspect  of 
extension.  The  sesamoid  bones  serve  to  strengthen  the  ar- 
ticulations to  which  they  are  attached,  they  also  increase 
the  power  of  the  muscles,  by  altering  the  direction  of  their 
tendons,  and  removing  them  further  from  the  axis  of  the 
bone  which  they  are  intended  to  move. 


PART   V, 


DISSECTION  OF  THE  JOINTS. 

WHEN  all  the  muscles,  vessels,  nerves,  &e.,  have  been 
dissected,  the  student  may  examine  the  anatomy  of  the 
joints ;  different  sections  of  these  should  be  made,  and 
when  the  principal  soft  parts  are  removed,  they  should  be 
subjected  to  maceration  for  two  or  three  days.  T.he  several 
parts  of  the  osseous  system  when  connected  either  by  natu- 
ral or  artificial  media,  constitute  the  skeleton  ;  the  attach- 
ment between  two  or  more  bones  is  denominated  an  articu- 
lation or  a  joint,  of  which  there  are  great  varieties  in  the 
frame ;  they  may,  however,  all  be  reduced  to  three  classes, 
the  rnoveable  or  diarthrosis,  the  immoveable  or  synarthrosis, 
and  the  mixed  or  amphiarthrosis. 

1.  DJARTHROSIS,  or  the  moveable,  includes  all  the  per- 
fectly moveable  joints,  and  presents  three  species,  viz.  en- 
arlhrosis,  arthrodia,  gingtymus ;  the  first  resembles  the  ball 
and  socket ;  the  second  is  a  modification  of  the  first,  the 
surfaces   being  nearly  plane ;  the  third  is  the  hinge  or 
trochlea,  and  is  more  complex. 

2.  SYNARTHROSIS,  or  the  immoveable  includes  four  species, 
viz.  suture,  gomphosiz,  schyndylesis,  and  sympliysis.     Suture  is 
the  serrated  interlocking  observable  between  the  bones  of 
the  head,  in  most  instances  the  opposed  edges  are  indented 
like  the  teeth  of  a  saw,  in  some  few  they  meet  by  rather 
plane  surfaces,  (harmonia,)  and  in  others  they  are  scaly, 
and  one  overlaps  the  other,  (squamous  suture.)     Gomphosis 
is  seen  in  the  connexion  between  the  teeth  and  their  sockets, 
and  schyndelesis  between  the  vomer  and  the  other  parts  com- 
posing the  septum  narium  ;  symphysis  is  seen  in  the  pelvis, 
between  the  ossa  ilii  and  the  sacrum,  and  between  the  ossa 
pubis ;  the  last  named  example,  however,  is  placed  by  some 
among  the  mixed  articulations. 

3.  AMPHIARTHROSIS,  or  the  mixed,  include  those  cases  in 
which  the  bones  are  connected  by  an  Intervening  substance, 


488  DUBLIN    DISSECTOR. 

and  enjoy  very  obvious  motion,  as  the  bodies  of  the  verte- 
bra^ &c. 

All  the  moveable  articulations  include  several  structures 
differing  in  use  and  organization,  viz.  the  extremities  of  two 
or  more  bones,  these  are  covered  by  cartilage  ;  a  synovial 
membrane,  covered  by  a  fibrous  capsule,  or  by  accessory 
ligaments  and  fasciae,  they  may  also  contain  inter-articular 
cartilages  and  ligaments,  also  reddish  vascular  adipose 
masses.  The  articular  or  incrusting  cartilages  adhere  al- 
most inseparably  to  the  ends  of  the  bones,  they  are  smooth 
and  elastic,  composed  of  fibres  which  are  placed  perpen- 
dicular to  the  bone,  they  are  thickest  on  the  most  convex 
part  of  the  heads  of  bones,  and  on  the  circumference  of 
the  articular  cavities. 

The  inter-articular  cartilages  or  fibro-cartilagcs  are  very 
elastic,  the  fibrous  tissue  in  some  of  them  is  very  evident; 
many  of  these  are  attached  to  the  circumference  of  the 
cavities  forming  the  glenoid  or  cotyloid  ligaments  which 
serve  to  deepen  the  cavity,  and  to  prevent  the  hard  edges 
of  the  bones  striking  against  each  other;  some  inter-ar- 
ticular cartilages  are  moveable,  as  in  the  temporo-maxillary 
and  knee  joints,  all  these  bodies  serve  either  to  deepen 
the  cavities,  or  to  attach  the  bones  more  closely,  or  to  lessen 
shocks. 

Synovial  membranes  of  joints  <ire  very  thin  sacs  similar  to 
the  bursoe,  allied  also  to  the  great  serous  membranes,  inas- 
much as  they  exhale  and  absorb  a  fluid,  and  are  shut,  bags 
without  any  opening,  they  are  on  the  whole,  however,  more 
vascular  and  less  elastic  than  the  true  serous  membrane  ; 
the  synovia  also,  or  the  fluid  which  the  former  secrete,  is  a 
glairy  unctuous-feeling  fluid,  very  different  from  the  fine 
exhalation  of  the  latter.  Every  synovial  membrane  litres 
the  fibrous  capsule  or  accessory  coverings,  is  thence  re- 
flected over  the  inter-articular  cartilages  or  ligaments  when 
present,  and  over  the  articular  or  incrusting  cartilages,  and 
in  some  cases  over  portions  of  the  bones  themselves ;  on 
the  cartilages  the  membrane  is  so  fine  and  delicate  as  to  be 
incapable  of  perfect  demonstration,  except  under  the  influ- 
ence of  maceration  or  disease.  In  some  articulations,  the 
synovial  membrane  is  complicated  in  its  arrangement,  be- 
ing folded  round  tendons  or  ligaments  as  in  the  hip  and 
shoulder,  or  thrown  into  processes  which  contain  fat  and 
vessels  so  as  to  resemble  a  vascular  or  glandular  mass; 
such  growths  exist  in  the  knee  and  in  many  other  joints, 
and  have  been  improperly  considered  glands  or  follicles 
by  Havers  and  others. 

[The  trrm  a-ticulation  or  arthrosis  is  generic,  and  we  may  properly 
divide  arthrosis  into  three  classes,  which  division  is  foundt- d  upon  two 


DUBLIN    DISSECTOR.  489 

/ircumstances  ;  on  the  one  hand,  the  existence  or  non-existence,  of  a 
«ynovial  membrane  and  on  the  other  hand,  the  amount  of  motion  al- 
lowed to  the  articulation.  Thus  in  the  first  class,  diarthrosis  there  is 
always  a  synovial  membrane  more  or  less  extensive,  arid  a  synovial 
fluid  more  or  less  abundant.  In  the  second  and  third  classes  synar- 
throsis  and  amphiarthrosis,  there  is  no  synovial  membrane.  Again 
in  diarthrosis  there  is  free  motion,  in  synarthrosis  there  is  no  motion, 
and  in  amphiarthrosis  there  is  a  certain  amount  of  motion,  but  stiil 
no  synovial  membrane.  Each  of  these  classes  are  modified  in  parti- 
cular joints,  so  as  to  present  us,  with  several  varieties,  diarthrosis  has 
three  varieties,  arthrodia  in  which  the  head  of  one  bone  is  received 
upon  the  superficial  cavity  of  another  bone,  as  at  the  shoulder  joint ; 
enarthrosis  in  which  the  head  of  one  bone  is  received  into  a  deep 
cavity  in  another  bone,  as  at  the  hip  joint ;  ginglymus  or  hinge  joint 
of  two  forms,  angular,  as  the  elbow  joint,  lateral  or  rotatory,  as  be- 
tween the  radius  and  ulna.  The  most  perfect  specimen  of  the  hinge 
like  joint  is  at  the  ankle.  Synarthrosis  (which  means  without  articu- 
lation or  without  motion,)  has  four  varieties;  sutura  having  serrated 
edges,  as  in  most  of  the  bones  of  the  cranium  ;  Harmonia,  when 
two  edges  nearly  even  are  placed  in  apposition,  as  in  some  of  the  ar- 
ticulations of  the  head  and  face  ;  Gomphosis,  resembling  the  junction 
between  a  nail  and  the  board  into  which  it  is  driven,  as  in  the  articu- 
lations of  the  teeth,  with  the  alveolae  ;  Schyndylesis,  where  the  edge 
of  one  bone  is  grooved  and  the  other  sharp  as  in  the  articulations  of 
the  vomer  ;  this  articulation  is  like  tae  junction  between  the  chrystal 
and  the  rim  of  a  watch ;  Amphiarthrosis,  (from  derivatives  signify- 
ing both  and  articulation,  because  it  partakes  of  the  characters  of 
both  of  the  other  classes,  in  not  having  a  synovial  membrane,  and 
yet  having  motion,)  has  three  varieties  ;  Syndesmosis  or  articulation 
by  ligaments,  exceedingly  common,  and  found  at  all  of  the  diarthrodial 
joints ;  Syssarcosis,  or  junction  by  means  of  muscles,  of  which  the 
most  perfect  example,  is  in  the  union  of  the  scapula  with  the  trunk  ; 
Synchrondrosis  or  articulation  by  means  of  cartilage  or  nbro-cartilage, 
as  between  the  bodies  of  the  vertebae  ;  there  are  several  articulations 
of  this  latter  variety,  which  are  looked  upon  by  some,  as  a  fourth 
variety  and  which  are  called  symphyses  viz.  the  symphysis  pubis,  the 
two  sacro  iliac  symphyses,  and  the  symphysis  menti  of  the  child. 

The  following  table  will  present  at  a  glance  the  different  classes 
and  varieties  of  articulation. 

t  Arthrodia 
Diarthrosis,          <  Enarthrosis, 


r  Sutura, 
I  Harmonia. 
Synarthrosis,       j  QomphoS, 

[  Schindylesis, 

/  Syndesmosis, 
Amphiarthrosis,  )  Syssarcosis, 

f  Synchrondrosis,^  Symphyais. 


490  DUBLIN    DISSECTOR. 

Of  all  these  articulations  those  which  have  the  most  free  and  ex- 
tensive motion  of  the  diarthrodial  class,  are  the  most  liable  to  disloca. 
tion,  and  of  these  the  shoulder  joint,  is  the  one  most  often  luxated. 
When  dislocated,  those  joints  are  most  easily  reduced  in  which  the 
articular  surfaces  are  most  plane,  but  it  is  more  difficult  to  keep  them 
in  place  after  reduction,  while  the  reverse  of  these  propositions  is  true 
in  the  decided  ball  and  socket  joints.  Again  fhe  diarlhrodial  joints 
are  those  most  liable  to  disease,  particula;ly  in  strumous  habits ;  of 
these  joints  the  hip  and  the  knee  are  more  often  affected  than  any 
others.  The  disease  may  involve  all  the  structures  of  the  joint,  that 
is,  the  synovial  membrane,  the  cartilage,  and  the  bone,  or  it  may  be 
confined  to  one  structure  only  ;  in  the  latter  case,  it  is  the  synovial 
membrane  which  suffers,  and  the  inflammation  may  terminate  by  re- 
solution, or  assume  a  more  chronic  form,  and  present  an  hy drops  ar- 
ticuli.  In  other  cases,  the  inflammation  may  extend  to  the  cartilage 
and  even  to  the  bone,  attended  by  suppuration,  ulceration,  and  absorp- 
tion. This  absorption  in  the  hip  joint,  is  sometimes  so  great  as  to 
cut  off  the  head  of  the  femur,  and  produce  a  displacement  of  the  bone, 
resembling  dislocation  on  the  dorsum  of  the  ilium. 

Inflammations  of  the  joints  not  unfrequently  terminate  in  anchy. 
losis,  which  occurs  under  two  forms,  partial  and  complete.  Partial 
anchylosis  is  the  result  of  adhesive  inflammation  of  the  synovial  mem- 
brane, and  effusion  of  fibrine  around  the  joint  causing  a  stiffness  of 
the  ligaments,  and  a  thickening  of  the  cellular  tissue  ;  these  cases 
may  often  times  be  cured  by  passive  motion,  either  manual  or  instru- 
mental, and  other  collateral  means,  the  modus  operand!  of  which  is 
chiefly  to  produce  absorption  of  the  effused  substances.  True  or 
complete  anchylosis  occurs  in  those  cases,  where  there  is  an  absolute 
loss  of  the  synovial  membrane  and  the  cartilage,  so  that  the  bones 
come  in  contract  and  are  fused  together,  or  united  by  the  adhesive 
inflammation.  This  form  occurs  most  commonly  at  the  knee,  hip, 
and  elbow  joints,  and  is  incurable  except  by  resorting  to  a  severe  sur- 
gical operation.  There  is  one  point  of  great  practical  importance  to 
be  attended  to,  in  the  treatment  of  cases  where  we  apprehend  anchy. 
losis,  if  the  disease  is  in  the  hip,  or  the  knee  joint,  the  limb  should  be 
kept  in  the  extended  position,  if  in  the  elbow  joint,  the  fore  arm 
should  be  about  serni-flexed  upon  the  arm,  or  in  other  words,  the  limb 
should  become  anchylosed  in  that  position,  in  which  it  will  be  of  most 
use  to  the  patient.  In  old  people  it  is  not  at  all  uncommon  to  find 
the  bones  of  the  head  anchylosed,  and  also  the  bodies  of  the  vertebras 
by  the  ossification  of  the  inter-vertebral  cartilages.  In  the  diarthroidal 
joints,  most  commonly  at  the  knee  and  elbow,  false  cartilages  some* 
times  form,  they  are  at  first  connected  with  the  synovial  membrane, 
by  a  stnall  pedicle  which  is  frequently  broken,  and  they  then  float  in 
the  joint,  and  getting  between  the  bones,  throw  the  patient  down  ; 
they  vary  in  number  from  one  to  twenty-five,  usually  not  more  than 
three  or  four,  and  in  size,  from  a  mustard  seed  to  a  large  pea,  but  oc- 
casionally are  much  larger.  They  may  be  removed  by  a  valvular  in. 
cision  into  the  joint  and  when  nicely  dried,  resemble  a  grain  of 
oopped  corn.] 


DUBLIN    DISSECTOR.  491 


TEMFORO-MAXILLARY   ARTICULATIONS. 

These  are  examples  of  double  arthruJia,  they  have  also 
some  of  the  characters  of  ginglymus.  Each  condyle  of 
the  inferior  maxilla,  being  received  into  that  portion  of  the 
glenoid  cavity  of  the  temporal  bone  which  is  anterior  to 
the  fissure,  each  also  moves  on  the  transverse  root  of  the 
zygoma  ;  these  joints  are  strengthened  by  an  external  and 
internal  lateral,  an  inter  and  a  stylo-maxillary  ligament, 
and  by  an  imperfect  but  rather  strong  capsular  ligament, 
which  "contains  an  inter-articular  cartilage  and  two  synovial 
membranes. 

The  external  lateral  ligament  is  short  and  narrow,  it  arises 
from  the  root  of  the  zygomatic  process  of  the  temporal 
bone,  descends  obliquely  backwards,  and  is  inserted  nar- 
row into  the  outer  side  of  the  neck  of  the  condyle  of  the 
lower  jaw :  it  is  covered  by  the  skin  and  the  parotid  gland, 
and  it  adheres  to  the  capsular  ligament,  of  which  it  seems 
to  be  but  a  thickened  fasciculus. 

The  internal  lateral  ligament  is  thinner  and  longer  than 
the  external,  it  arises  narrow  from  the  spinous  process  of 
the  sphenoid  bone,  descends  obliquely  forwards,  and  is  in- 
serted broad  into  the  inner  margin  of  the  orifice  of  the  infe- 
rior dental  canal ;  this  aponeurotic  band  corresponds  ex- 
ternally to  the  capsule  and  to  the  external  pterygoid  mus- 
cle above,  and  lower  down  to  the  internal  maxillary  ves- 
sels, and  to  the  dental  vessels  and  nerve  which  intervene 
between  it  and  the  bone ;  its  inner  surface  rests  on  the  in- 
ternal pterygoid  muscle,  which  it  thus  bears  off  from  com- 
pressing the" dental  nerve  and  vessels. 

The  inter-maxillary  ligament  scarcely  deserves  the  name 
of  ligament,  it  is  rather  a  dense  vertical  aponeurotic  band, 
common  to  the  buccinator  and  superior  constrictor  of  the 
'he  pharynx,  attached  above  to  the  external  pterygoid  pro- 
cess and  adjacent  surface  of  the  superior  maxillary  bone, 
and  below  to  the  root  of  the  coronoid  process  of  the  inferior 
maxilla. 

The  stylo-maxillary  ligament  is  a  thin  aponeurosis,  which 
arises  from  the  styloid  process  of  the  temporal  bone,  passes 
forwards  and  outwards  ;  is  connected  to  the  cervical  fas- 
cia, and  to  the  stylo-glossus  muscle,  and  is  inserted  into  the 
angle  of  the  lower  maxilla,  between  the  masseter  and  in- 
ternal pterygoid  muscles,  and  between  the  parotid  and 
sub-maxillary  glands  ;  this  ligament  does  not  properly  be- 
long to  the  articulation,  it  is  rather  intended  to  strengthen 
the  cervical  fascia,  and  to  increase  the  surface  of  attach- 
ment for  the  stylo-glossus  muscle. 

The  capsular  ligament  consists  of  dense  fibres  which  arise 


492  DUBLIN    DISSECTOR 

from  the  margin  of  the  zygomatic  eminence,  and  from  the 
glenoid  fissure,  as  they  descend  they  adhere  to  the  synovial 
membranes  and  to  the  inter-articular  cartilage,  and  are  in- 
serted into  the  neck  of  the  lower  jaw;  this  ligament  is  co- 
vered posteriorly  by  the  parotid  gland  and  adipose  sub- 
stance, externally  and  internally  by  the  lateral  ligaments, 
and  in  part  by  the  external  pterygoid  muscles,  it  is  defi- 
cient at  the  anterior  and  internal  part  to  admit  the  insertion 
of  the  external  pterygoid  muscle,  into  the  inter-articular 
cartilage,  and  into  the  neck  of  the  bone  ;  it  is  wider  above 
than  below,  and  it  is  prolonged  very  low  down  upon  the 
bone  behind. 

The  synovial  membranes,  one  the  larger  or  superior,  covers 
the  cartilaginous  surface  of  the  zygomatic  eminence  and 
the  glenoid  cavity,  and  is  reflected  over  the  upper  surface 
of  the  inter-articular  cartilage  :  the  other,  the  lower  or 
smaller,  covers  the  under  surface  of  the  inter-articular  car- 
tilage and  is  reflected  over  the  condyle  on  which  it  is  pro- 
longed more  posteriorly  than  in  front,  these  sacs  in  general 
have  no  communication  with  each  other. 

The  inter-articular  fibro-cartilage  is  transversely  oval, 
thick  in  its  circumference,  thin  in  the  centre.  Its  upper 
surface  is  adapted  to  the  articular  eminence,  and  to  the 
forepart  of  the  glenoid  cavity,  being  concave  before  and 
convex  behind,  and  its  lower  surface,  which  is  smaller  fits 
on  the  condyle.  Some  fibres  of  the  external  pterygoid  are 
attached  to  its  forepart,  the  capsular  and  external  lateral 
ligament  also  adheres  to  it :  sometimes  there  is  a  hole  in 
the  centre  of  it,  through  which  the  synovial  membranes 
may  communicate.  This  cartilage  is  composed  of  very 
close  concentric  fibres,  which  are  more  distinct  at  the 
circumference,  it  has  no  direct  attachment  to  bone  as  the 
inter-articular  cartilages  in  some  other  joints,  it  therefore 
partakes  less  of  a  ligamentous  nature  ;  it  serves  to  strength- 
en the  articulation,  and  thus  to  guard  against  displacement 
by  presenting  to  each  condyle  a  moveable  socket,  which 
prevents  its  slipping  off  the  articular  eminence  of  the  tem- 
poral bone,  on  which  the  condyle  rests  every  time  the  mouth 
is  fully  opened;  this  cartilage  also  serves  to  lessen  fric- 
tion in  the  joint,  as  well  as  the  effects  of  concussion  gen- 
erally. The  motions  of  the  lower  jaw  are  not  very  con- 
spicuous at  the  articulations  but  are  considerable  towards 
the  forepart  of  the  bone;  this  can  be  depressed,  ele- 
vated, moved  backwards,  forwards,  and  towards  either 
side;  in  depression  of  the  chin  the  condyles  advance  and 
descend  a  little  so  as  to  rest  on  the  transverse  roots 
of  the  zygomatic  processes ;  in  elevation  the  condyl( 
are  behind  these  roots  in  the  glenoid  depressions,  in  rot 


DUBLIN    DISSECTOR.  493 

tion  the  condyles  move  alternately,  one  being  the  fixed 
point  for  the  other,  thus,  in  moving  the  chin  to  the  right 
side,  the  right  condyle  is  fixed  in  the  glenoid  cavity,  while 
the  left  advances  and  descends  a  little,  and  the  contrary 
state  occurs  in  moving  the  chin  towards  the  left  side ; 
these  motions  occur  rapidly  and  alternately  in  masti- 
cating or  grinding  the  food  ;  they  have  been  fully  ex- 
plained in  the  chapter  on  the  muscles,  (page  24.)  The 
condyles  of  the  lower  jaw  are  very  liable,  one  or  both,  to 
dislocation,  this  can  only  occur  in  the  anterior  direction ; 
when  both  condyles  are  thus  displaced,  the  accident  is 
termed  a  perfect  dislocation,  when  only  one  condyle,  it  is 
a  partial  dislocation ;  in  the  perfect  form  the  mouth  is 
opened  and  cannot  be  closed,  as  the  coronoid  process 
strikes  against  the  malar  and  maxillary  bones,  the  teeth  of 
the  lower  jaw  are  on  a  plane  anterior  to  those  of  the  upper, 
there  is  also  a  depression  in  front  of  each  ear,  and  the  tem- 
poral muscles  seem  elongated,  articulation  and  deglutition 
are  much  impaired.  When  the  partial  dislocation  occurs, 
the  chin  is  turned  a  little  towards  the  opposite  side,  and  the 
other  symptoms  exist  in  a  less  marked  degree  ;  dislocation 
of  this  bone,  either  perfect  or  partial,  is  caused  by  the  spas- 
modic action  not  merely  of  the  depressing  muscles,  but 
principally  of  the  external  pterygoid,  assisted  by  the  inter- 
nal pterygoid  and  the  superficial  lamina  of  the  masseter ; 
when  the  mouth  is  wide  open,  we  can  readily  conceive 
how  those  muscles,  particularly  the  external  pterygoid,  can 
draw  forwards  the  condyles  from  off  the  articular  emi- 
nences of  the  zygomatic  processes,  into  the  temporal  fossae 
under  the  zygoma,  and  place  them  between  the  arch  and 
the  temporal  muscle  :  in  general,  but  little  injury  is  inflict- 
ed on  any  of  the  ligaments  of  the  articulation,  the  internal 
lateral  and  part  of  the  capsule  may  be  lacerated,  the  ele- 
vator muscles  are  tense,  also  the  inter-rnaxillary  ligament, 
the  external  pterygoid,  and  the  depressors  are  relaxed. 
Dislocations  of  this  bone  cannot  occur  in  the  child  under 
four  years  of  age,  in  consequence  of  the  peculiar  form 
of  the  jaw,  the  angle  being  so  obtuse,  and  the  ramus  di- 
rected so  obliquely  forwards  and  downwards. 

ARTICULATION   OF    THE   OCCIPUT    WITH    THE   ATLAS. 

THIS  is  a  double  arthrodia,  the  condyles  of  the  occipital 
bone  being  received  into  the  superior  oblique  processes  of 
the  atlas,  and  secured  by  capsular  ligaments,  by  synovial 
membranes  which  cover  the  opposed  cartilaginous  surfaces, 
and  by  an  anterior  and  posterior  ligament. 

The  capsular  ligament  on  each  side,  arises  from  the  cir- 
42 


494  DUBLIN    DISSECTOR. 

cumference  of  the  condyle,  and  is  inserted  into  that  of  the 
glenoid  cavity  of  the  atlas ;  these  ligaments  are  sufficient- 
ly loose  to  allow  of  slight  motion,  and  are  strongest  exter- 
nally. The  synomal  membranes  line  the  interior  of  each 
capsule,  and  are  reflected  over  the  opposed  cartilaginous 
surfaces  of  the  condyle  and  the  cavity. 

Anterior  and  'posterior  occipilo-allantal  ligaments,  arise  from 
the  edges  of  the  foramen  magnum,  and  are  inserted  into  the 
upper  border  of  the  atlas,  before  and  behind  its  oblique 
processes;  they  are  covered  by  the  deep  seated  muscles  of 
the  spine,  the  obliqui  and  recti  both  before  and  behind ; 
the  anterior,  which  is  narrow,  rests  on  the  odontoid  process 
and  its  ligaments.,  the  posterior,  which  is  broader,  is  on  the 
dura  mater,  and  is  pierced  on  either  side  for  the  vertebral 
vessels  and  sub-occipital  nerves,  In  these  arthrodial  artic- 
ulations, no  horizontal  rotatory  motion  can  occur  ;  flexion 
and  extension,  or  a  forward  and  backward  movement  of 
the  head,  and  a  very  slight  lateral  flexion,  or  what  are 
termed  the  "nodding  actions"  of  the  head,  are  the  only 
motions  which  can  take  place. 

ARTICULATION    OF    THE    OCCIPUT    WITH    THE   AXIS   OR   SECOND 
VERTEBRA. 

The  occipital  bone,  though  not  in  contact  with,  is  yet 
connected  to  the  axis  by  the  two  lateral  or  moderator  liga- 
ments, and  by  the  apparatus  ligamentosus  colli,  this  may 
therefore  be  considered  as  an  example  of  amphiarthrosis  or 
syndesmosis.  To  expose  these  ligaments,  the  cervical  por- 
tion of  the  spine  must  be  divided  vertically,  immediately 
behind  the  oblique  processes ;  so  as  to  separate  the  spinous 
processes  with  their  crura,  from  the  bodies,  the  dura  mater 
being  then  removed  from  the  fore  part  of  the  section,  we 
obtain  a  view  of  the  cuneiform  process  of  the  occiput,  and 
of  the  posterior  surface  of  the  bodies  of  the  vertebrae  co- 
vered by  ligaments. 

The  apparatus  ligamentosus  is  a  flat  fasciculus  of  fibres, 
which  descends  from  the  lower  part  of  the  cuneiform  pro- 
cess, behind  the  odontoid  process,  and  is  inserted  in  the 
middle  thin  into  the  superior  part  of  the  transverse  ligament 
of  the  atlas,  and  below  this  into  the  body  of  ihe  second  verte- 
bra, and  on  either  side  very  thick  into  the  bodies  of  the  se- 
cond, third  and  fourth  vertebra? ;  on  the  latter  it  becomes 
continuous  with  the  posterior  common  vertebral  ligament ; 
this  ligament,  therefore,  is  common  to  the  occiput,  and  to  the 
three  or  four  superior  cervical  vertebrae :  the  central  band 
of  this  is  the  perpendicular  ligament  of  old  writers,  and  has 
been  described  incorrectly  as  inserted  into  the  point  of  the 


DUBLIN    DISSECTOR.  495 

odontoid  process.  This  ligament  covers  the  odontoid  pro- 
cess and  the  following  ligament ;  it  serves  to  attach  the  head 
to  the  cervical  vertebrae,  and  to  bind  down  and  secure  the 
lateral  ligaments,  it  also  resists  too  much  flexion  of  the  neck. 
The  lateral  [oblique  or  moderator}  ligaments  arise  one  from 
each  side  of  the  odontoid  process,  they  ascend  obliquely 
outwards,  and  are  inserted  into  a  depression  on  the  inner 
side  of  each  condyle;  these  short  and  strong  ligaments  are 
covered  posteriorly  or  towards  the  canal  by  that  last  de- 
scribed, anteriorly  they  are  covered  by  cellular  tissue,  and 
by  the  anterior  occipito-atlantal  ligaments.  These  liga- 
ments have  little  or  no  influence  over  flexion  or  extension, 
but  they  check  or  regulate  the  degree  of  rotatory  motion 
between  the  axis  and  the  atlas,  and  in  rotation  of  the  head, 
the  occiput  and  the  atlas  form  but  one  system,  which  rolls 
on  the  pivot-like  process  of  the  second  vertebra  or  axis. 
To  the  point  of  the  odontoid  process  there  is  no  ligament 
attached,  a  little  filamentous  cellular  tissue  sometimes  as- 
cends from  it  to  the  anterior  edge  of  the  foramen  magnum. 

ARTICULATION    BETWEEN    THE   FIRST    AND    SECOND   VERTEBRA, 
OR    THE   ATLAS    AND    AXIS. 

THESE  two  vertebrae  present  three  articulations,  one  in 
the  centre  between  the  odontoid  process  and  the  body  of 
the  atlas,  and  two  lateral  between  the  oblique  processes, 
these  may  all  be  considered  arthrodial  surfaces,  the  atlas 
being  the  recipient  for  the  three,  the  central  one  is  vertical 
and  the  deepest,  the  lateral  are  horizontal  and  superficial. 
The  central  articulation  is  secured  by  a  transverse  liga- 
ment and  two  synovial  membranes,  and  the  lateral  joints 
possess  the  usual  capsular  and  synovial  apparatus  ;  the 
two  vertebrae  are  also  connected  by  an  anterior  and  poste- 
rior ligament  similar  to  the  occipito-atlantal. 

The  transverse  ligament  is  behind  the  odontoid  process,  it 
describes  the  fourth  of  a  circle,  it  is  thick,  broad  and  fibro- 
cartilaginous  in  the  centre,  is  attached  on  each  side  to  the 
inner  edge  of  each  oblique  process  of  the  atlas,  and  is  con- 
nected in  the  centre  by  some  of  the  fibres  of  the  apparatus 
ligamentosus,  to  the  cuneiform  process  superiorly,  and  to 
the  body  of  the  axis  inferiorly.  The  synovial  membranes 
are  connected  one  to  the  posterior  surface  of  the  odontoid 
process,  and  to  the  anterior  surface  of  this  ligament,  the 
other  synovial  membrane  covers  the  opposed  cartilaginous 
surfaces  of  the  atlas  and  the  processus  dentatus  :  by  means 
of  this  ligament  a  circular  chamber  or  collar  is  formed, 
which  encloses  the  axoid  process  and  binds  it  to  the  atlas, 
while  the  two  synovial  sacs  are  beautiful  provisions  to  ad- 
mit of  the  partial  rotation  of  the  latter  around  the  former, 


496  DUBLIN    DISSECTOR. 

in  which  movements  the  head  and  atlas  may  be  consider- 
ed as  one  solid  piece,  they  not  having  any  independent  or 
separate  rotatory  motion.  The  importance  of  the  trans- 
verse ligament  is  great  and  obvious,  hence  when  ruptured 
as  has  happened  in  disease  of  this  central  articulation, 
death  has  been  instantaneous,  the  head  has  fallen  forwards 
and  the  odontoid  process  projecting  backwards  has  either 
compressed  or  pierced  the  medulla  oblongata. 

The  lateral  articulations  are  secured  by  capsular  liga- 
ments and  synovial  membranes,  which  are  sufficiently  lax  to 
admit  of  the  necessary  rotatory  motions,  these  ligaments 
are  attached  to  the  circumference  of  the  oblique  processes, 
and  are  lined  by  loose  and  well  moistened  synovial  mem- 
branes, which  are  thence  reflected  on  the  cartilaginous  sur- 
faces of  the  opposed  bones ;  the  vertebral  vessels  are  in 
contact  with  these  capsules. 

The  anterior  and  posterior  atlanto  axoid  ligaments  are  of  but 
little  importance,  their  name  implies  their  attachment ;  the 
anterior  is  narrower  and  stronger  than  the  posterior,  which 
is  thin,  broad  and  weak. 

THE   COMMON   ARTICULATIONS    OF   THE   VERTEBRJE. 

The  vertebral  column  consists  of  a  great  number  of 
parts,  which  are  so  connected  as  to  combine  with  consider- 
able elasticity  and  flexibility  sufficient  strength  to  support 
the  whole  frame,  as  well  as  to  afford  security  to  the  im- 

Eortant  nervous  organ  it  contains ;  from  the  inferior  sur- 
ice  of  the  second  cervical  to  that  of  the  last  lumbar  ver- 
tebra, one  similar  series  of  ligaments,  though  somewhat 
differently  modified  in  the  different  regions,  serves  to  unite 
the  several  vertebrae  to  each  other  and  to  connect  the  whole 
into  one  upright  and  powerful  column.  The  bodies  of 
every  pair  are  an  example  of  amphiarthrosis,  the  oblique 
processes,  of  very  flat  arthrodin,  and  the  other  processes  of 
syndesmosis. 

The  ligaments  are  classed  into  two  sets,  those  which 
unite  the  bodies,  and  those  which  unite  the  processes  ;  the 
first  comprise  the  anterior  and  posterior  common  vertebral 
ligaments  and  the  intervertebral  fibro-cartilages  or  liga- 
ments ;  the  second  set  include  the  capsules  and  synovial 
membranes  of  the  oblique  processes,  the  infra-spinous  or 
yellow  ligaments  or  the  ligaments  of  the  lamina?  or  crura 
of  the  spinous  processes,  the  inter-spinous,  the  supra-spi- 
nous,  and  the  inter-transverse. 

The  bodies  of  the  vertebrae  are  united  by  an  anterior,  a 
posterior,  and  an  inter- vertebral  ligament. 

The  anterior  -vertebral  ligament  is  a  strong  band  of  fibres 
extending  from  the  axis  to  the  sacrum,  and  adhering  to  the 


DUBLIN    DISSECTOR.  497 

bones,  particularly  to  their  edges  and  to  the  intervertebral 
substances :  some  of  the  fasciculi  are  very  long,  others 
very  short,  and  some  of  the  deep  fibres  cross  obliquely  be- 
tween the  bodies  of  the  vertebras ;  this  ligament  is  narrow 
in  the  cervical  and  superior  lumbar  regions,  broader  and 
more  distinct  in  the  dorsal  and  lower  lumbar :  in  the  neck 
and  loins  its  edges  are  confounded  with  the  adjacent  ten- 
dons ;  its  relations  are  obvious ;  it  serves  to  attach  the  ver- 
tebrae, to  strengthen  the  inter-vertebral  ligaments,  and  to 
oppose  excessive  extension  of  the  column. 

The  posterior  vertebral  ligament  is  partly  prolonged  from 
the  apparatus  ligamentosus,  it  extends  down  the  back  part 
of  the  bodies  of  the  vertebrae,  along  the  front  of  the  spinal 
canal ;  it  consists  of  smooth  glistening  fibres,  is  narrow  in 
the  dorsal,  and  broad  in  the  cervical  region:  it  adheres 
more  closely  to  the  edges  of  the  vertebras  and  to  the  inter- 
vertebral  ligaments  than  to  the  middle  of  each  vertebra, 
from  which  it  is  separated  by  vessels;  the  dura  mater  can 
be  easily  detached  from  it,  its  margins  present  a  series  of 
lunated  processes  from  its  being  prolonged  more  laterally 
on  each  intervertebral  ligament  than  on  the  vertebra  itself 
where  it  is  narrowed ;  this  ligament,  like  the  last,  gives 
strength  to  the  spine,  it  also  opposes  too  much  flexion  of 
the  column. 

The  intervertebral  ligaments  or  fibro-cartilag-es  are  placed 
between  the  bodies  of  all  the  vertebras  except  that  of  the 
first  and  second:  these  substances  partake  of  the  fibrous 
or  ligamentous  character  much  more  than  the  cartilagi- 
nous ;  they  are  united  above  and  below  to  the  flat  surfaces 
of  the  vertebras  in  so  intimate  a  manner  that  maceration 
alone  can  separate  them  completely,  and  their  own  strength 
and  cohesion  surpass  even  that  of  the  bones  themselves, 
they  are  covered  and  bound  down  by  the  anterior  and  pos- 
terior ligaments :  in  the  neck  and  loins  they  are  thicker 
in  front  than  behind,  and  the  contrary  in  the  back,  hence 
in  a  great  degree  the  peculiar  curvatures  of  the  spinal 
column.  Their  structure  is  peculiar  and  complex,  it  is  best 
examined  in  the  lumbar  region ;  a  horizontal  section  ex- 
hibits an  arrangement  of  tough,  fibrous  laminas  apparently 
concentric,  yet  not  exactly  so,  for  they  decussate  or  inter- 
sect and  overlap  each  other,  these  laminas  are  more  nume- 
rous in  front  and  on  the  sides  than  behind;  towards  the 
surface  they  are  very  compact  and  close,  but  as  they  pass 
more  inwards  they  leave  interstices  which  are  filled  with  a 
soft,  pulpy,  whitish,  semi-fluid  substance,  and  towards  the 
centre  or  a  little  behind  that  point,  the  fibrous  tissue  be- 
comes rather  cellular,  the  areolas  being  filled  with  this 
viscid  pulp :  the  external  layers  are  the  strongest  and  most 


498  DUBLIN    DISSECTOR. 

elastic,  and  often  present  a  cartilaginous  appearance,  and 
in  old  persons,  some  portions  of  these  are  occasionally 
found  ossified ;  a  vertical  section  of  these  substances  also 
exhibits  the  fibrous  structure  and  the  different  density  of 
its  different  portions;  in  this  view,  the  fibres  are  distinctly 
seen  passing  from  one  bone  to  another  in  such  oblique 
courses  that  they  completely  decussate;  in  this  section 
also  the  ligamentous  tissue  swells  out  and  expands  beyond 
the  limit  of  the  bony  surfaces,  owing  partly  to  the  elastic 
resistance  of  the  external  layers  being  then  removed  ;  when 
these  ligaments  are  subjected  to  maceration,  they  swell, 
become  very  full  and  tense,  and  if  cut  horizontally  the 
central  fluid  portion  will  be  found  to  rise  up  like  a  conical 
pulpy  pivot.  The  intervertebral  substance  is  more  perfect 
in  the  adult  than  in  the  very  young  or  very  aged,  in  the 
latter  the  pulpy  substance  is  less,  and  is  yellowish  and  dry, 
and  the  whole  ligament  is  diminished  in  depth  and  in  elas- 
ticity, whereas  in  the  very  young  the  fluid  portion  is  thin- 
ner and  in  greater  quantity,  it  is  also  of  a  lighter  colour, 
and  sometimes  presents  a  rosy  tint.  These  ligaments  serve 
to  increase  the  height  or  length  of  the  spine  without  adding 
much  to  its  weight,  to  connect  most  firmly  its  several  com- 
ponent pieces,  to  complete  the  spinal  canal,  also  the  sockets 
for  the  heads  of  the  ribs,  to  permit  of  yielding  or  flexibil- 
ity in  the  column  to  a  great  degree,  to  restore  the  spine  to 
its  vertical  bearing  by  their  elasticity,  which  is  one  of  their 
most  remarkable  and  superior  properties,  to  lessen  the  ef- 
fects of  concussion,  and  to  prevent  shocks  being  trans- 
mitted from  the  lower  limbs  to  the  brain ;  they  constitute 
the  spine  a  sort  of  strong,  flexible,  and  elastic  spring,  in 
which,  while  they  admit  of  sufficient  yielding  in  every  di- 
rection, they  at  the  same  time  resist  too  much  flexion,  ex- 
tension, lateral  or  rotatory  motion. 

The  oblique,  or  articulating  processes  of  the  vertebra? 
are  connected  by  synovial  membranes,  and  by  ligamentous 
fibres  extended  irregularly  around  these,  so  as  to  form  im- 
perfect capsular  ligaments. 

The  ligamenia  subjlava  are  between  the  back  parts  of  the 
plates  of  the  vertebrae ;  these  ligaments  close  the  intervals 
between  the  vertebras,  and  thus  complete  the  back  part  of 
the  spinal  canal :  they  exist  between  all  the  vertebrae  from 
the  second  to  the  sacrum,  are  most  distinct  in  the  loins,  and 
are  seen  best  from  the  interior  of  the  canal ;  they  are  com- 
posed of  dense,  yellow,  elastic  fibres,  united  angularly  to 
each  other  towards  the  base  of  each  spinous  process  :  these 
ligaments  close  the  spinal  canal  posteriorly  between  the 
spinous  processes,  they  also  resist  too  much  flexion  of  the 
column.  The  spinous  processes  of  the  vertebrae  are  also 


DUBLIN    DISSECTOR.  499 

connected  to  each  other  by  ligamentous  bands,  termed  su- 
pra-spinous  and  inler-spinous  (the  ligamenta  sub-flava  may 
be  called  in/ra-spinous.)  Between  the  transverse  processes 
also  ligamentous  fibres,  exist  which  are  named  inter-trans- 
verse ligaments. 

[The  ligamentum  nuchcc  is  attached  to  the  occipital  protuberance 
superiorly,  and  is  attached  to  the  spines  of  the  cervical  vertebrae  as 
low  as  the  seventh,  and  is  lost  upon  the  cervical  aponeurosis.  It 
tends  to  support  the  head  in  the  erect  position,  and  to  prevent  its  too 
great  flexion.  In  the  human  subject  it  is  comparatively  very  small,  but 
in  quadrupeds,  it  is  very  strong  and  large,  so  as  to  support  the  weight 
of  the  head,  which  is  placed  at  the  end  of  a  long  horizontal  lever  (the 
vertebral  column  ;)  it  is  however  very  extensible  and  elastic,  as  is 
shown,  by  the  case  with  which  these  animals  carry  their  heads  to  the 
ground,  as  in  grazing,  arid  raise  them  again,  to  the  natural  position, 
which  last  motion  is  effected  by  the  elasticity  of  the  ligament  and 
the  powerful  muscles  of  the  neck.] 

A  dislocation  of  the  head  from  the  atlas  has  been  only 
found  in  consequence  of  disease.  The  first  cervical  verte- 
bra may  be  dislocated  from  the  second,  either  as  a  conse- 
quence of  disease  or  by  a  violent  rotation  of  the  head,  or 
by  a  fracture  of  the  processus  dentatus.  Dislocation  of 
one  vertebra  is  extremely  rare,  and  is  perhaps  never  sim- 
ple but  complicated  with  violent  injury  to  the  bones,  liga- 
ments, and  muscles. 

ARTICULATION   BETWEEN    THE    PELVIS   AND   THE   SPINE  : LIGA- 
MENTS   OF    THE    PELVIS. 

The  last  lumbar  vertebra  is  joined  to  the  sacrum  in  the 
same  manner  as  the  other  vertebrae  are  joined  to  each  other. 

The  two  last  lumbar  vertebrae  are  connected  to  the  ilium 
by  the  ilio-lumbar  ligament ;  this  is  sometimes  divided  into 
two,  it  arises  from  the  transverse  processes  of  the  fifth  and 
fourth  lumbar  vertebrae  and  from  the  back  part  of  the 
sacrum,  proceeds  horizontally  outwards,  and  is  inserted  into 
the  posterior  superior  spinous  process  and  crest  of  the 
ilium. 

The  several  bones  of  the  pelvis  are  connected  together 
by  ligaments  and  cartilages ;  the  ilium  and  sacrum  are 
firmly  united  by  a  cartilage  which  consists  of  two  thin 
layers,  they  are  each  somewhat  semi-circular,  and  adhere 
to  each  bone ;  behind  this  they  are  connected  by  short  liga- 
mentous fibres,  which  are  intermingled  with  a  soft  cellular 
tissue  ;  the  synchondrosis  in  front  of  this  is  rather  loose  in 
the  child,  and  presents  an  indistinct  synovial  surface  with 
a  little  reddish  fluid ;  in  the  adult  a  soft  yellowish  matter 
intervenes,  the  surfaces  are  then,  however,  very  uneven  and 


500  DUBLIN    DISSECTOR. 

appear  indented  with  one  another ;  in  the  aged  they  are 
sometimes  anchylosed. 

[The  junctions  between  the  sacrum  and  ossa  innominata  are  called 
the  right  and  left  sacro  iliac  sympkyses,  and  the  ligamentous  fibres 
are  divided  into  the  sacro  spinous,  and  the  sacro  iliac  ligaments.  The 
first  extends  between  the  posterior  superior  spinous  process  of  the 
ilium,  and  the  third  and  fourth  spines  of  the  sacrum  ;  the  second  sur 
rounds  the  articulation,  and  is  strongest  posteriorly.] 

The  sacro-sciatic  are  two  in  number  on  each  side ;  first, 
the  posterior  or  great  sacro-sciatic  ligament,  arises  broad  from 
the  lower  and  back  part  of  the  posterior  inferior  spine  of 
the  ilium  and  from  the  back  part  of  the  sacrum  and  coccyx ; 
descends  obliquely  outwards,  becomes  narrow  and  thick, 
and  is  inserted  again  broad  into  the  lower  and  inner  edge  of 
the  tuber  ischii ;  its  posterior  surface  is  covered  by  the 
glutaeus  maximus ;  a  falciform  process  is  continued  for- 
wards along  the  ramus  of  the  ischium,  to  this  the  obturator 
fascia  is  attached,  this  serves  to  conduct  and  protect  the 
pudic  vessels  and  nerves. 

Second,  the  anterior  or  lesser  sacro-sciatic  ligament  crosses 
in  front  of  the  former,  is  triangular,  arises  broad  from  the 
side  of  the  sacrum  and  coccyx,  passes  outwards  and  is  in- 
serted narrow  into  the  spine  of  the  ischium.  These  four 
ligaments  are  situated  at  the  lower  and  back  part  of  the 
pelvis,  they  serve  to  secure  the  sacrum  and  ossa  coccygis 
to  the  ossa  innominata,  they  also  assist  in  forming  the 
parietes  of  the  pelvis,  and  by  their  decussation  they  con- 
stitute the  two  openings  on  each  side  known  by  the  names 
of  the  greater  and  lesser  sacro-sciatic  notches,  the  larger 
and  superior  of  which  transmits  the  glutoeal  nerves  and 
vessels,  the  pyriform  muscle  and  the  sciatic  and  pudic 
nerves  and  vessels;  through  the  inferior  or  lesser  the  inter- 
nal obturator  tendon  and  the  pudic  vessels  pass. 

The  coccyx  is  united  to  the  sacrum  by  ligamentous  bands 
before  and  behind,  [the  anterior  and  posterior  sacro  coccygeal 
ligaments]  also  by  a  substance  resembling  the  inter-verte- 
bral, but  which  is  not  so  laminated,  nor  does  it  contain  any 
of  the  pulpy  material. 

The  oval  surfaces  of  the  ossa  pubis  are  closely  attached 
by  several  laminse  of  fibro-cartilage,  which  resemble  the 
inter-vertebral,  and  which  are  thicker  before  than  behind 
where  a  little  fluid  separates  these  bones  which  are  each 
covered  by  cartilage,  the  fibres  pass  in  vertical  concentric 
laminse  which  intersect  each  other,  some  of  these  are  con- 
tinued all  round,  others  are  deficient  behind,  they  are  thicker 
above  and  below;  in  the  centre  there  is  generally  a  little 
viscid  fluid,  and  an  imperfect  membranous  appearance,  a 
strong  tendino-ligamentous  substance  covers  it  in  front  [the 


DUBLIN    DISSECTOR.  501 

anterior  pubic  ligament;]  this  articulation  is  strengthened  in- 
feriorly  by  the  [sub-  or  inter]- pubic  ligament,  which  is  very 
dense,  it  adheres  to  and  passes  from  the  ramus  of  one  bone 
to  the  opposite. 

[This  articulation  is  called  the  symphysis  pubis.] 

The  obturator  ligament  is  a  thin  fascia  adhering  to  the 
margin  of  the  obturator  hole,  except  superiorly,  where  it  is 
deficient  to  allow  the  thyroid  nerve  and  vessels  to  pass  out 
obliquely. 

[This  ligament  by  its  two  surfaces  gives  origin  to  the  external  and 
internal  obturator  muscles.] 

ARTICULATIONS   OF   THE   RIBS. 

The  true  ribs  are  joined  to  the  vertebrse  behind  and  to 
the  sternum  before;  the  false  or  the  five  inferior  ribs  are 
only  indirectly  connected  to  the  latter  :  each  of  the  verte- 
bral articulations,  with  few  exceptions  [the  first,  eleventh, 
and  twelfth,  sometimes  the  tenth,]  involves  two  vertebra? 
and  the  intermediate  substance, 'the  head  of  each  rib  pre- 
sents two  slight  convex  surfaces,  which  are  received  into 
the  depression  on  the  sides  of  the  bodies  of  two  vertebrae, 
and  the  intermediate  ridge  or  angle  is  connected  by  liga- 
ments to  the  inter- vertebral  substance  ;  the  tubercle  of  each 
rib  is  also  articulated  to  the  concavity  on  the  forepart  of  the 
transverse  process  of  the  inferior  of  the  two  vertebra,  with 
whose  bodies  the  head  of  the  rib  is  articulated  :  [except  the 
eleventh  and  twelfth  which  have  no  tubercle ;]  thus  the 
posterior  end  of  each  rib  presents  three  articulations,  two 
on  the  head  and  one  on  the  tubercle ;  these  all  belong  to 
the  class  arthrodia,  the  vertebne  forming  the  recipient  sur- 
faces ;  the  internal  vertebral  articulation,  or  that  of  the  head 
of  the  rib,  is  secured  by  an  anterior  or  stellate  ligament,  two 
synovial  membranes,  and  the  inter-articular  ligament :  the 
tubercle  is  secured  in  its  socket  by  a  synovia!  membrane, 
and  by  an  external,  posterior,  and  superior  costo-trans- 
verse  ligament. 

First,  the  capsular  or  stellate  or  anterior  ligament,  arises 
from  the  front  of  the  head  of  the  rib,  and  thence  extends 
over  the  two  synovial  membranes  in  a  radiated  manner, 
and  is  inserted  by  three  bands  into  the  side  of  the  vertebra 
above  and  below,  and  into  the  inter- vertebral  substance. 

The  inter-articular  ligament  arises  from  the  projecting  ridge 
in  the  articular  surface  of  the  rib,  is  short  and  somewhat 
yellowish,  and  is  inserted  into  the  cavity  in  the  inter-verte- 
bral substance  in  which  the  head  is  received. 

[This  ligament  is  wanting  at  the  first,  eleventh,  and  twelfth  ribs,  be. 
cause  they  are  articulated  to  the  corresponding  vertebra)  only ;  the 
same  is  sometimes  true  of  the  tenth.] 


502  DUBLIN    DISSECTOR. 

The  upper  and  lower  divisions  of  this  joint  are  lined  by 
distinct  synovial  membranes,  which  do  not  communicate; 
the  stellate  ligament  and  these  synovial  membranes  are  co- 
vered by  the  pleura,  the  thoracic  ganglions  of  the  sympa- 
thetic nerve,  and  on  the  right  side  by  the  vena  azygos ; 
the  first,  eleventh,  and  twelfth,  have  only  one  synovial 
membrane  and  no  inter-articular  ligament,  there  being  only 
one  articulating  surface  on  their  heads,  which  are  joined  to 
only  one  vertebra  each. 

The  tubercle  of  each  rib  presents  two  surfaces  separated 
by  a  ridge,  the  external  is  rough  for  the  attachment  of  li- 
gaments, the  internal  is  convex  and  covered  with  cartilage, 
and  is  received  into  the  articulating  depression  at  the 
summit  of  the  transverse  process  of  the  inferior  of  the 
two  vertebrae,  to  the  bodies  of  which  the  head  is  attach- 
ed ;  a  synovial  membrane  and  three  ligaments  secure  this 
articulation. 

The  synovial  membranes  of  these  external  costo-ver- 
tebral  joints,  are  more  loose  and  distinct  than  those  of  the 
heads  of  the  ribs  :  the  eleventh  and  twelfth  ribs  are  not  ar- 
ticulated to  transverse  processes,  and  have  only  very  slight 
tubercles. 

There  are  three  ligaments  termed  costo-trans verse  ;  the 
posterior,  the  middle,  and  the  anterior;  these  secure  the 
connexion  of  the  ribs  to  the  transverse  processes  of  the 
vertebrae,  the  two  first  of  these  connect  the  rib  to  its  cor- 
responding vertebra  or  transverse  process,  but  the  last  con- 
nects this  transverse  process  to  the  rib  beneath  ;  thus,  these 
three  ligaments  arise  from  the  one  transverse  process,  two 
are  attached  to  the  corresponding  rib,  and  the  third  to  the 
rib  beneath. 

Posterior  or  external  costo-transverse  ligament,  flat,  and 
somewhat  square,  arises  from  the  posterior  surface  of  the 
extremity  of  the  transverse  process,  passes  outwards,  and 
is  inserted  into  the  rough  non-articular  portion  of  the  tu- 
bercle of  the  corresponding  rib  ;  this  ligament  exists  on  all 
the  ribs,  though  very  loose  on  the  two  last. 

The  middle  costo-transverse  ligament,  connects  the  back 
part  of  the  rib  to  the  front  of  the  corresponding  transverse 
process,  it  is  a  short,  thick,  inter-osseous  ligament,  which 
cannot  be  seen  until  a  horizontal  section  of  the  part  be 
made,  or  the  rib  forcibly  torn  from  the  process. 

[This  ligament  is  wanting  at  the  eleventh  and  twelfth  ribs,  which 
have  no  tubercle.] 

Anterior  or  internal  costo-transverse  is  wanting  in  the  first 
and  twelfth  ribs,  arises  narrow  from  the  lower  border  of  the 
transverse  process,  descends  obliquely  inwards  and  for- 


DUBLIN    DISSECTOR.  503 

wards,  and  is  inserted  broad  into  the  upper  edge  of  the  rib 
beneath,  the  inter-costal  vessels  and  nerves  lie  upon  it,  ex- 
ternally it  is  continuous  with  the  inter-costal  aponeurosis, 
internally  it  bounds  the  opening  through  which  the  poste- 
rior branches  of  the  inter-costal  nerves  and  vessels  pass. 
From  the  double  mode  of  articulation  of  the  ribs,  but  little 
motion  can  occur,  and  that  only  a  slight  elevation  and  de- 
pression with  a  very  little  rotation  :  from  the  length  how- 
ever of  the  ribs,  this  motion  has  a  considerable  effect  an- 
teriorly and  laterally  in  enlarging  the  thorax;  all  these 
ligaments  are  relaxed  during  inspiration.  Simple  dislo- 
cations of  the  vertebral  ends  of  the  ribs  can  never  occur. 
The  cartilages  of  the  ribs  at  their  costal  ends  are  convex, 
and  are  very  closely  united  to  the  concave  surfaces  in  the 
extremities  of  the  bones,  by  symphysis  or  rather  gompho- 
sis.  The  sternal  ends  of  the  cartilages  of  the  seven  true 
ribs,  except  the  first,  are  convex,  adapted  to  the  hollows  in 
the  edge  of  the  sternum  ;  these  hollows  are  covered  by  car- 
tilage and  by  synovial  membranes ;  each  joint  is  strength- 
ened by  ligamentous  bands,  which  proceed  from  the  carti- 
lage before  and  behind  the  articulation,  and  are  expanded 
upon  the  sternum. 

[These  may  be  called  the  costo  sternal  ligaments.} 
There  is  no  distinct  joint  between  the  first  rib  and  the 
sternum,  the  cartilage  and  bone  appear  to  be  continuous ; 
that  of  the  second  is  sometimes  divided  into  two  cavities  ; 
the  cartilages  of  the  three  superior  false  ribs  are  connected 
to  that  of  the  last  of  the  true  ribs,  and  the  two  last  are  un- 
connected. 

[The  cartilage  of  the  eighth  rib  on  one  side,  is  sometimes  articu- 
lated to  the  sternum  ;  we  have  seen  this  on  the  left  side.  The  car. 
tilage  of  the  seventh  rib  is  usually  connected  by  a  ligament  running 
from  its  inferior  margin  to  the  front  of  the  xiphoid  cartilage  the  costo 
xiphoid  ligament.] 

Dislocations  of  the  costal  or  outer  ends  of  the  cartilages 
of  the  ribs  are  very  rare;  they  sometimes  however  occur; 
those  of  the  sternal  end  are  still  more  uncommon. 

LIGAMENTS   OF   THE   SUPERIOR   EXTREMITIES. 

THESE  comprise  first,  the  ligaments  which  connect  the 
clavicle  to  the  sternum  ;  second,  those  connecting  the  cla- 
vicle to  the  scapula :  third,  those  proper  to  the  scapula ; 
fourth,  those  connecting  the  humerus  to  the  scapula;  fifth, 
those  connecting  the  bones  of  the  elbow  joint,  which  will 
be  afterwards  subdivided;  sixth,  those  of  the  wrist  joint; 
seventh,  those  of  the  metacarpus ;  eighth,  those  of  the  pha- 
langes of  the  fingers. 


504  DUBLIN    DISSECTOR. 

1.   STERNO-CLAVICULAR   ARTICULATION. 

THE  articulating  end  of  the  clavicle  is  larger  than  the 
surface  of  the  sternum,  the  former  is  triangular,  the  apex 
behind  and  below,  the  surface  of  the  sternum  is  slightly 
convex  from  before  backwards,  and  concave  from  within 
and  from  above  downwards  and  outwards,  the  cartilage  of 
the  first  rib  assists  in  forming  its  lower  extremity,  this  ar- 
ticulating surface  on  the  sternum  is  inclined  outwards  and 
a  little  backwards,  and  is  more  on  the  posterior  than  the 
anterior  aspect  of  the  bone  :  the  circumference  of  the  cla- 
vicle is  rough  for  ligamentous  attachment,  its  articulating 
surface  is  inclined  downwards  and  forwards,  is  uneven  and 
slightly  concave  from  before  backwards,  and  convex  from 
above  downwards.  This  articulation  is  secured  by  an  an- 
terior, posterior,  inferior,  and  inter-clavicular  ligament, 
also  by  an  inter-articular  cartilage  and  two  synovial  mem- 
branes. 

The  anterior  [sterno-davicular]  ligament  arisen  narrow  from 
the  end  of  the  clavicle,  descends  inwards,  and  is  inserted 
broad  into  the  forepart  of  the  sternum,  this  broad  liga- 
ment is  covered  by  the  skin,  and  by  the  tendon  of  the 
sterno-mastoid  muscle,  it  covers  and  adheres  closely  to 
the  synovial  membranes  and  to  the  inter-articular  car- 
tilage. 

The  posterior  \ster  no-clamcular~\  ligament  takes  a  course  be- 
hind the  joint  parallel  to  the  preceding,  it  is  narrower  and 
weaker  than  the  last. 

The  inferior  or  the  coslo-clamcular  or  rhomboid  ligament, 
passes  from  the  lower  surface  of  the  sternal  end  of  the  cla- 
vicle downwards,  forwards,  and  inwards,  and  is  inserted 
into  the  cartilage  of  the  first  rib,  this  ligament  closes  the 
angle  between  the  clavicle  and  the  first  rib,  its  upper  or 
posterior  surface  is  in  contact  with  the  subclavian  vein,  it 
serves  to  confine  the  clavicle  in  its  place,  and  to  resist  its 
dislocation  upwards,  it  also  prevents  the  sterno-mastoid 
muscle  separating  the  clavicle  from  the  chest. 

The  inter -clavicular  ligament  extends  from  the  posterior 
surface  of  one  clavicle  to  the  other,  the  deep  cervical  fas- 
cia is  attached  to  the  upper  concave  edge  of  this  ligament, 
its  lower  border  is  generally  attached  to  the  posterior  lip  of 
the  sternum,  it  is  covered  by  the  integuments,  and  it  lies 
on  the  sterno-hyoid  muscles,  it  connects  the  clavicles  to 
each  other  and  to  the  sternum,  it  also  protects  the  soft  parts 
immediately  above  the  latter. 

The  inter-articular  cartilage  is  nearly  circular,  it  is  thin 
below  and  attached  to  the  sternum,  thick  above  and  attach- 
ed  to  the  clavicle,  it  is  very  thin  and  often  perforated  in  the 


DUBLIN    DISSECTOR.  505 

centre,  the  sterno-clavicular  ligaments  adhere  to  it  before 
and  behind  ;  it  serves  to  adapt  the  two  slanting  bony  surfaces 
to  each  other,  it  also  binds  them  together  like  a  true  lig- 
ament. 

The  synovial  membranes  are  connected  to  each  surface  of 
this  cartilage,  they  are  generally  very  dry  and  often  inter, 
cepted  by  ligamentous  bands. 

2.    SCAPULO-CLAVICULAR    ARTICULATION. 

THE  oval  end  of  the  clavicle  is  connected  to  the  end  of 
the  acromion  process,  in  a  plane  arthrodial  joint,  which 
is  secured  by  a  superior  and  inferior  [acromio  clavicular]  liga- 
ment, these  are  attached  to  the  surfaces  of  each  bone ; 
there  is  also  an  indistinct  synovial  membrane  between  both  ; 
and  sometimes  there  is  an  inter-articular  cartilage,  the  del- 
toid and  trapezius  muscles  also  strengthen  this  articulation 
considerably,  and  adhere  very  closely  to  these  ligaments. 
The  two  following  ligaments  do  not  properly  belong  to  this 
articulation,  they  are,  however,  very  essential  in  connecting 
the  scapula  and  clavicle,  they  are  about  an  inch  to  the  in- 
ner side  of  the  scapulo-clavicular  articulation ;  these  are 
the  conoid  and  trapezoid  [or  anterior  and  posterior  coraco  cla- 
vicular] ligaments. 

The  conoid  is  the  posterior  and  the  smaller  of  the  two, 
its  base  is  attached  to  a  tubercle  on  the  lower  surface 
of  the  clavicle,  its  apex  to  the  broad  part  of  the  coracoid 
process. 

The  trapezoid  is  more  anterior  and  external,  it  is  also 
broader  and  stronger  than  the  conoid,  it  is  about  an  inch 
distant  from  the  articulation,  and  is  attached  above  to  an 
oblique  line  on  the  clavicle,  thence  it  descends  obliquely 
inwards  to  the  upper  part  of  the  coracoid  process ;  these 
ligaments  are  united  posteriorly  and  externally,  anteriorly 
they  are  distinct,  the  extremity  of  the  subclavian  muscle 
intervening,  and  sometimes  a  small  bursa.  The  coraco  or 
costo-clavicular  fascia,  though  not  a  ligament,  serves  to 
strengthen  the  connexion  between  the  clavicle  and  sca- 
pula, as  also  between  both  these  and  the  first  rib.  (See 
page  69.) 

[This  is  sometimes  called  the  ligamentum  bicorne.] 

The  clavicle  at  its  sternal  end  may  be  dislocated  for- 
wards. Displacement  upwards  or  backwards  is  too  rare  to 
merit  any  notice. 

[The  dislocation  backwards  is  usually  caused  by  curvature  of  the 
spine,  and  hence  is  for  the  most  part  irremediable.  In  this  case  the 
eternal  end  of  the  clavicle  projects  behind  the  sternum  and  com- 
presses  the  trachea  and  oesophagus,  so  as  to  interfere  with  respiration 
and  deglutition.] 


506  DUBLIN    DISSECTOR. 

In  a  perfect  dislocation  forwards  the  anterior,  posterior, 
costo-clavieular  and  inter-clavicular  ligaments  are  ruptured ; 
and  occasionally  the  tendinous  expansion  of  the  sterno- 
cleido-mastoid  muscle.  At  its  scapular  extremity,  the 
clavicle  may  be  displaced  either  above  or  below  the  acro- 
mion  ;  the  latter  ease  is  extremely  rare,  almost  unknown  ; 
dislocation  of  this  end  of  the  clavicle  is  less  frequent  than 
that  of  the  sternal  extremity :  when  tne  clavicle  passes 
above  the  acromion,  the  shoulder  inclines  in,  being  unsup- 
ported by  this  bone,  and  its  extremity  projects  under  the 
skin  of  the  shoulder.  The  superior,  inferior,  and  some 
fibres  of  the  coraco-clavicular  ligaments  are  ruptured.  The 
clavicular  portion  of  the  trapezius,  by  elevating  the  clavi- 
cle, assists  in  this  displacement. 

3.    LIGAMENTS   OF   THE   SCAPULA. 

THESE  are  two  in  number,  an  anterior  and  posterior. 

The  anterior  or  the  deltoid  or  coraco-acromial,  arises  broad 
from  the  coracoid  process,  passes  upwards,  and  is  inserted 
narrow  into  the  point  of  the  acromion  process ;  this  broad 
thin  triangular  ligament  is  often  deficient  or  weak  in  the 
centre,  it  is  covered  by  the  deltoid  muscle  and  the  clavicle, 
and  it  lies  over  the  large  bursa  which  covers  the  tendon  of 
the  supra-spinatus  muscle:  this  ligament  completes  the 
protecting  arch  or  vault  which  the  acromion  and  coracoid 
processes  nearly  complete  over  the  shoulder  joint. 

[This  is  sometimes  called  the  triangular  ligament.] 

The  posterior  or  coracoid  ligament  arises  from  the  costa 
of  the  scapula  behind  the  notch,  passes  forwards,  and  is 
inserted  into  the  base  of  the  coracoid  process ;  it  converts 
the  notch  into  a  foramen  :  this  ligament  is  sometimes  want- 
ing, then  the  notch  is  completed  into  a  hole  by  bone  :  the 
supra  scapular  nerve  usually  passes  beneath  this  ligament, 
while  the  vessels  of  this  name  run  above  it. 

[This  is  also  called  the  ligamentum  posticum  scapulae.] 

4.    HUMERO-SCAPULAR   OR   SHOULDER   ARTICULATION. 

THE  head  of  the  humerus  is  retained  in  the  glenoid  cavi- 
ty by  the  capsular  and  coraco-humeral  or  accessory  liga- 
ments, the  joint  is  also  furnished  with  the  glenoid  ligament, 
and  a  synovial  membrane :  this  joint  may  be  regarded  as 
an  enarthrosis,  though  in  the  dry  skeleton  it  appears  to  be 
only  an  arthrodia. 

The  glenoid  ligament  deepens  the  glenoid  cavity ;  this 
fibrous  border  is  partly  derived  from  the  tendon  of  the 
biceps  ;  is  thick  where  it  adheres  to  the  bone,  its  free  edge 


DUBLIN    DISSECTOR.  507 

is  thin,  it  is  covered  on  both  surfaces  by  synovial  mem- 
brane. 

The  capsular  ligament  arises  around  the  neck  of  the  scap- 
ula, increasing  in  size  it  encircles  the  head  of  the  humerus, 
and  is  inserted  into  its  neck ;  it  is  dense  above  and  below, 
thin  internally  and  externally  ;  this  capsule  is  very  loose 
and  long,  the  tendons  of  the  four  capsular  muscles  are 
identified  with  it,  and  to  these  it  is  principally  indebted  for 
its  strength  ;  it  is  almost  perfectly  covered  by  these,  a  small 
portion,  however,  interiorly,  and  a  little  internally,  that  is, 
between  the  tendon  of  the  sub-scapular  muscle  and  that 
of  the  long  portion  of  the  triceps  is  deprived  of  this  sup- 
port, accordingly  in  this  situation,  although  the  ligament 
itself  is  here  rather  strong,  dislocations  of  this  joint  usual 
ly  occur. 

The  coraco-humeral  or  accessory  ligament  extends  obliquely 
downwards  and  outwards  from  the  coracoid  process  to  the 
anterior  part  of  the  great  tuberosity,  where  it  becomes 
confounded  with  the  capsule  and  with  the  tendon  of  the 
supra-spinatua  muscle. 

The  synovial  membrane  is  reflected  over  the  glenoid  sur- 
face, around  the  glenoid  ligament,  it  then  lines  the  fibrous 
capsule  and  the  tendons  of  the  adjacent  muscle,  and  is  next 
reflected  over  the  head  of  the  humerus,  it  also  lines  the 
bicipital  groove  by  a  process  of  about  an  inch  and  a  half 
long :  there  are  generally  small,  red,  fatty  masses  under 
this  membrane  near  the  edge  of  the  scapula,  and  on  the 
neck  of  the  humerus. 

The  shoulder  joint,  from  the  great  extent  of  its  motions 
and  form  of  its  articulating  surfaces,  is  more  liable  to  dis- 
location than  any  other  in  the  body  ;  this  accident  may  be 
primary  or  secondary. 

Primary  dislocations  of  the  humerus  may  occur  down- 
wards  or  into  the  axilla,  forwards  or  under  the  pectoral 
muscles,  or  backwards  into  the  infra-spinous  fossa :  this 
latter  species  is  extremely  rare;  a  dislocation  upwards 
could  not  occur  without  fracture  of  the  acromion,  and 
therefore  cannot  be  considered  among  simple  dislocations. 
A  primary  dislocation,  either  directly  backwards  or  di- 
rectly forwards,  is  not  likely  to  happen,  as  the  strong  at- 
tachments of  the  teres  minor,  supra  and  infra-spinati  mus- 
cles to  the  greater  tubercle  of  the  humerus,  and  that  of  the 
sub-scapular  to  the  lesser  tubercle,  respectively  offer  pow- 
erful resistance  in  either  of  these  directions.  It  is  plain 
from  the  construction  of  this  joint,  that  a  dislocation  down- 
wards is  the  most  likely  to  occur ;  for  the  lower  part  of  the 
capsular  ligament  being  unsupported  by  muscles,  is  most 
weak ;  and  the  action  of  the  levator  muscles  of  the  shoul- 


508  DUBLIN    DISSECTOR. 

der,  by  rotating  the  head  of  the  humerus  from  above  down, 
will  bring  the  head  of  the  bone  near  the  inferior  edge  of 
the  glenoid  cavity,  and  thus  place  it  in  a  situation  most  fa- 
vourable for  displacement,  when  violence  is  applied  to  the 
extended  arm.  The  greater  extent  however  of  the  glenoid 
cavity  from  above  down  than  across,  tends  to  guard  against 
this  accident,  also  the  mobility  of  the  scapula  and  the  gle- 
noid cavity  being  held  opposed  to  the  head  of  the  humerus 
by  different  muscles,  but  above  all  by  those  which  cover 
and  adhere  to  the  capsule. 

When  the  humerus  is  dislocated  downwards,  the  head  of 
the  bone  is  found  resting  on  the  inferior  or  sternal  costa 
of  the  scapula,  between  the  long  head  of  the  triceps  and 
sub-scapularis.  The  lower  portion  of  the  capsular  liga- 
ment is  ruptured,  together  with  the  tendon  of  the  sub- 
scapularis.  The  tendons  of  the  supra  and  infra-spinati 
muscles  and  of  the  teres  minor  are  sometimes  lacerated, 
and  occasionally  the  tubercles  are  broken.  Some  of  the 
fibres  of  the  deltoid,  pectoralis  major,  and  coraco-brachia- 
lis  are  also  sometimes  torn ;  the  long  tendon  of  the  biceps 
usually  but  not  always  remains  unbroken.  Independent 
of  external  violence,  the  elevating  muscles  of  the  humerus, 
and  of  the  whole  arm,  (if  the  elbow  joint  be  fixed,)  with 
the  pectoralis  major,  latissimus  dorsi,  and  teres  major,  may, 
under  certain  circumstances,  effect  this  displacement  of  the 
bone.  The  deltoid  and  supra-spinatus  muscles  are  those 
which  most  powerfully  resist  reduction. 

When  the  head  of  the  humerus  is  dislocated  forwards, 
it  lies  on  the  inner  side  of  the  neck  of  the  scapula,  between 
it  and  the  second  and  third  ribs,  the  serratus  rnagnus  and 
sub-scapularis  generally  intervene.  The  internal  portion 
of  the  capsular  ligament  and  sometimes  the  tendon  of  the 
sub-scapularis  are  ruptured. 

In  dislocation  of  the  humerus  backwards,  the  head  of 
the  bone  lies  in  immediate  contact  with  the  scapula,  under 
the  infra-spinatus  muscle.  The  humerus  is  sometimes 
partially  dislocated  in  cases  of  paralysis  of  the  deltoid 
and  of  the  capsular  muscles,  or  in  very  aged  and  debilita- 
ted persons. 

[A  partial  luxation  of  the  os  brachii  is  sometimes  spoken  of,  in 
which  the  head  of  the  bone  is  thrown  inwards,  against  the  coracoid 
process  of  the  scapula.  Another  luxation  described  as  consecutive, 
is  that  in  which  the  head  of  the  bone,  is  lodged  against  the  middle  of 
the  clavicle.  When  the  shoulder  joint  has  been  once  luxated,  it  is 
liable  to  a  repetition  of  the  displacement.  We  have  known  a  case  of 
a  man  of  about  thirty-five  years  old,  whose  shoulder  had  been  luxated 
thirty  times.] 


DUBLIN    DISSECTOR.  509 


5.   HUMERO-CUBITAL   ARTICULATION,    OR   THE   ELBOW   JOINT. 

IN  this,  which  is  one  of  the  most  perfect  ginglymoid  ar- 
ticulations, the  opposed  extremities  of  the  humerus,  ulna, 
and  radius  mutually  receive  each  other,  and  are  attached 
together  by  an  external  and  internal  lateral  and  by  an  an- 
terior and  posterior  ligament,  all  these  ligaments  are  so 
closely  connected  to  the  surrounding  muscles  as  to  be  with 
difficulty  separated  ;  there  is  no  distinct  capsular  ligament, 
although  the  aggregate  of  these  might  be  considered  as 
such. 

The  external  lateral  [or  br&chio  radial]  ligament  is  short  and 
flat,  arises  narrow  from  the  external  condyle,  and  is  inserted 
broad  into  the  annular  ligament  of  the  radius;  this  liga- 
ment is  confounded  with  the  tendons  of  the  supinator  and 
extensor  muscles. 

The  internal  lateral  [or  Irackio  ulnar  ligament]  arises  narrow 
from  the  inner  condyle,  and  is  inserted  in  a  radiated  man- 
ner into  the  inner  edge  of  the  coronoid  and  olecranon  pro- 
cesses, it  is  longer  and  broader  than  the  external,  is  some- 
what triangular,  and  divides  inferiorly  into  two  fasciculi, 
the  anterior  of  which  extends  to  the  coronoid  process,  and 
is  confounded  with  the  common  tendinous  origin  of  the 
muscles  of  the  fore  arm,  the  posterior  is  inserted  into  the 
olecranon  process,  is  covered  by  the  ulnar  nerve  and  con- 
nected to  the  adjacent  muscles ;  both  portions  adhere  to 
the  synovial  membrane.  These  lateral  ligaments  steady 
and  strengthen  this  articulation,  they  also  in  some  measure 
restrain  its  motions,  the  anterior  portion  of  each,  particu- 
larly of  the  internal,  being  tense  in  extension,  the  posterior 
in  flexion  of  the  joint:  a  distinct  band  of  fibres  extends 
from  the  anterior  to  the  posterior  part  of  the  insertion  of 
the  internal  lateral  ligament,  or  from  the  coronoid  to  the 
olecranon  process ;  in  fracture  of  the  latter,  the  broken 
piece  is  often  retained  in  its  situation,  according  to  Sir  A. 
Cooper,  by  this  ligament 

The  anterior  ligament  consists  of  thin  fibres  which  take 
an  irregular  direction  over  the  forepart  of  the  joint ;  they 
arise  chiefly  from  above  the  internal  condyle,  and  the  de*- 
pression  on  the  forepart  of  the  humerus;  they  thence 
spread  over  the  synovial  membrane,  and  over  some  reddish 
fatty  matter  which  is  behind  the  brachialis  anticus ;  some 
are  inserted  into  the  annular  ligament  of  the  radius,  and  the 
remainder  are  gradually  lost  on  the  synovial  membrane. 

The  posterior  ligament  is  not  so  distinct  as  the  anterior, 
unless  the  fore  arm  be  flexed ;  the  fibres  chiefly  extend  in 
a  transverse  direction  from  one  condyle  to  the  other ;  they 

43* 


510  DUBLIN    DISSECTOR. 

are  attached  to  the  synovial  membrane,  and  covered  by  the 
triceps,  and  anconseus. 

The  synovial  membrane  is  common  to  the  humero-cubital, 
and  cubito-radial  articulations;  this  membrane  descends 
from  the  forepart  of  the  humerus  behind  the  anterior  liga- 
ment, and  a  quantity  of  reddish  fatty  matter  which  inter- 
venes, to  the  neck  o£  the  radius  and  annular  ligament; 
round  which  it  forms  a  cul  de  sac,  is  prolonged  into  the 
two  sigmoid  cavities  of  the  ulna,  and  thence  is  reflected 
to  the  lateral  ligaments  and  to  the  triceps  tendon,  which 
leads  it  to  the  posterior  depression  on  the  humerus,  it  is 
thence  expanded  over  the  articular  eminences  at  the  lower 
end  of  this  bone,  it  is  looser  before  and  behind  than  on  the 
sides,  it  is  also  thicker  in  those  situations. 

RADIO-ULNAR    ARTICULATIONS. 

THESE  are  two,  a  superior  and  an  inferior,  they  are  both 
of  the  arthrodial  class  ;  in  the  superior  the  head  of  the  ra- 
dius is  received  into  the  lesser  sigmoid  cavity  of  the  ulna, 
and  is  retained  in  it  by  the  following  ligament. 

The  annular  [or  coronary]  ligament  forms  about  three- 
fourths  of  a  circle,  the  lesser  sigmoid  depression  in  the  ulna 
completing  it ;  it  arises  from  the  anterior,  and  is  inserted  into 
the  posterior  border  of  the  lesser  sigmoid  cavity  of  the  ul- 
na; this  ligament  is  lined  by  the  synovial  membrane  of 
the  joint,  it  encircles  the  head  and  neck  of  the  radius ;  it 
often  presents  a  cartilaginous  structure. 

The  oblique  [or  round]  ligament  is  a  small  round,  fibrous 
cord,  but  weak  and  irregular,  it  arises  from  the  root  of  the 
coronoid  process  of  the  ulna,  descends  obliquely  outwards, 
and  is  inserted  into  the  radius  below  its  tubercle';  it  is  on  a 
plane  anterior  to  the  inter-osseous  ligament,  and  it  sepa- 
rates the  flexor  digitorum  sublimis  from  the  supinator  radii 
brevis  muscle,  it  is  made  tense  in  supination. 

The  most  frequent  dislocation  of  the  elbow-joint  is  that 
of  both  radius  and  ulna  backwards.  This  accident  is  some- 
times complicated  with  a  fracture  of  the  coronoid  process. 
The  relation  of  the  articulating  surfaces  in  the  semi-flexed 
position  of  the  arm  is  such,  that  if  external  violence  be  ap- 
plied, the  coronoid  process  slips  behind  the  articular  pulley 
of  the  humerus  and  is  lodged  in  the  sigmoid  fossa,  while 
the  humerus  is  thrown  forwards  on  the  radius  and  ulna. 
The  external,  internal,  and  sometimes  the  annular  ligament 
of  the  radius  are  ruptured,  though  the  accident  may  occur 
without  injury  to  any  of  these  parts ;  occasionally  even 
the  biceps  and  brachialis  internus  suifer  from  the  violent 
projection  of  the  humerus,  and  the  brachial  artery  has  been 
known  to  have  been  ruptured  in  this  manner.  The  flexor 


DUBLIN    DISSECTOR.  511 

muscles  of  the  arm,  by  keeping  it  bent,  and  the  triceps  by 
its  contraction,  are  the  muscles  which  oppose  reduction. 
The  internal  condyle  of  the  humerus  and  the  olecranori 
present  two  prominent  points,  which  are  of  great  impor- 
tance in  assisting  us  to  detect  injuries  about  the  elbow- 
joint.  In  the  extended  position  of  the  arm  they  are  nearly 
on  the  same  line,  and  any  displacement  of  the  bones  will 
cause  a  corresponding  displacement  of  these  two  promi- 
nences. 

The  form  of  the  bones,  the  strength  of  the  lateral  liga- 
ments, and  the  numerous  muscles  surrounding  the  joint, 
prevent  a  complete  lateral  luxation  of  both  ulna  and  radius, 
while  a  luxation  forwards  cannot  occur  without  fracture  of 
the  olecranon. 

The  ulna  may  be  dislocated  backwards  on  the  os  hume- 
ri  without  being  accompanied  by  the  radius.  The  coronoid 
process  is  forced  over  the  pulley  of  the  humerus  into  the 
sigmoid  fossa,  and  the  olecranon  forms  a  prominent  pro- 
jection at  the  back  part,  the  fore  arm  and  hand  are  twist- 
ed inwards.  The  annular  and  accessory  ligaments  are 
ruptured,  and  sometimes  a  small  portion  of  the  inter-os- 
seous. The  action  of  the  triceps  will  contribute  to  keep 
the  bone  in  this  position,  while  on  the  contrary,  the  brach- 
ialis  internus  assists  in  the  reduction. 

The  radius  may  be  dislocated  at  its  humeral  extremity, 
either  backwards  or  forwards.  When  it  is  driven  through 
the  back  part  of  the  capsular  ligament  it  is  found  to  rest 
above  the  external  condyle  of  the  humerus,  supported  by 
the  brachial  fascia.  The  accessory  and  annular  ligaments 
are  torn,  and  sometimes  the  inter-osseous  ligament  suffers 
at  its  superior  part. 

In  dislocation  forwards  of  the  radius,  the  head  of  the 
bone  rests  above  the  external  condyle  of  the  os  humeri, 
and  resists  sudden  flexion.  The  accessory  and  annular 
ligaments,  with  a  portion  of  the  inter-osseous  ligament,  are 
ruptured  in  this  luxation  as  in  the  former.  The  biceps 
muscle  becomes  shorter  by  contraction  and  thus  may  re- 
sist, though  not  in  any  great  degree,  reduction. 

The  opposed  edges  of  the  shafts  of  both  radius  and  ulna 
are  connected  by  a  thin  aponeurosis,  the  inler-osseal  mem- 
brane, or  ligament;  it  is  composed  of  long  fibres  which  de- 
scend obliquely  inwards  from  the  radius  to  the  ulna,  others 
occasionally  cross  it  in  a  contrary  direction ;  this  ligament 
is  deficient  above  and  below,  and  in  many  places  is  perfo- 
rated by  vessels ;  it  is  not  made  very  tense  in  any  position 
of  the  limb,  it  serves  to  give  attachment  to  muscles. 

In  the  inferior  radio-vlnar  articulation  the  round  head  of 
the  ulna  is  received  into  the  sigmoid  cavity  of  the  radius, 


512  DUBLIN    DISSECTOR. 

and  retained  in  it  by  a  loose  synovial  membrane  or  the  sacci- 
form ligament,  which  is  covered  before  and  behind  by  some 
ligamentous  fibres,  which  form  an  imperfect  capsule,  it 
passes  from  the  radius  to  the  ulna,  and  forms  a  very  loose 
sac  above  the  following  ligament  or  cartilage ;  it  always 
contains  a  large  quantity  of  synovia. 

The  fibro-cartilage  is  triangular,  it  arises  narrow  from  the 
styloid  process  of  the  ulna,  and  is  inserted  broad  into  the 
inner  edge  of  the  carpal  end  of  the  radius  below  the  de- 
pression for  the  ulna,  which  bone  it  separates  from  the 
wrist  joint  or  from  the  cuneiform  bone,  its  anterior  and 
posterior  edges  are  connected  to  the  ligamentous  fibres  that 
pass  from  the  ulna  to  the  radius.  Sometimes  it  is  perfo- 
rated, then  the  wrist  joint  and  this  articulation  will  commu- 
nicate :  this  cartilage  appears  to  be  a  prolongation  of  the 
encrusting  cartilage  of  the  lower  end  of  the  radius,  it  serves 
to  unite  the  radius  and  ulna  very  securely,  while  at  the 
same  time  it  allows  the  former  to  roll  round  the  latter  as 
on  a  pivot,  this  cartilage  also  completes  the  ulnar  side  of 
the  carpal  articulation. 

The  carpal  extremity  of  the  radius  may  be  dislocated 
either  forwards  or  backwards ;  in  the  first  of  these  acci- 
dents, which  is  much  the  more  frequent,  this  bone  is 
thrown  forwards  on  the  scaphoid  and  os  trapezium ;  the 
capsular  and  anterior  ligaments  alone  are  ruptured.  In 
the  dislocation  backwards  the  back  part  of  the  capsule, 
the  posterior,  and  sometimes  the  external  lateral  ligament 
are  ruptured.  The  bone  projects  under  the  skin  at  the 
back  of  the  wrist. 

The  carpal  extremity  of  the  ulna  may  be  dislocated  for- 
wards or  backwards,  the  latter  is  more  frequent ;  the  acci- 
dent is  obvious,  and  the  dislocation  is  easily  reduced,  but 
there  is  much  difficulty  in  keeping  the  bone  in  its  place,  in 
consequence  of  the  rupture  of  the  sacciform  ligament. 

6.   RADIO-CARPAL   ARTICULATION,    OR   THE   WRIST   JOINT. 

IN  this  arthrodial  joint,  the  lower  end  of  the  radius  and 
the  inter-articular  cartilage  form  a  socket  for  the  scaphoid, 
lunar  and  cuneiform  bones,  the  two  former  are  received 
into  the  radius,  the  latter  corresponds  to  the  fibro-cartilage, 
which  separates  it  from  the  ulna  and  excludes  this  bone 
from  the  joint:  the  wrist  joint  is  secured  by  an  external 
and  internal  lateral,  by  a  posterior  and  anterior  ligament, 
and  by  a  synovial  membrane. 

The  external  lateral  or  radio-carpal  ligament,  arises  from  the 
styloid  process  of  the  radius,  and  is  inserted  into  the  scap- 
hoid bone  ;  some  fibres  extend  to  the  annular  ligament  and 
to  the  os  trapezium. 


DUBLIN    DISSECTOR.  513 

The  internal  lateral  or  ulna  carpal  ligament,  is  round  and 
long,  arises  from  the  styloid  process  of  the  ulna,  extends 
obliquely  downwards  and  forwards,  and  is  inserted  into  the 
cuneiform  bone. 

The  anterior  and  posterior  ligaments  descend  from  the 
radius  and  inter-articular  cartilage,  anteriorly  and  poste- 
riorly, and  are  inserted  into  the  superior  row  of  the  carpus, 
the  anterior  is  strong  and  tense,  the  posterior  is  weaker  and 
looser,  its  fibres  however  are  more  distinct,  the  former  is 
covered  by  the  flexor,  the  latter  by  the  extensor  tendons ; 
these  two  ligaments  together  with  the  two  lateral  may  be 
regarded  and  have  been  described  by  some,  as  the  capsular 
ligament. 

The  synovial  membrane  covers  the  superior  row  of  the 
carpal  bones,  is  thence  reflected  to  line  the  ligaments,  and 
is  continued  over  the  articular  surface  of  the  radius,  and 
of  the  inter-articular  cartilage ;  it  is  very  loose  and  con- 
tains much  synovia  ;  when  the  bones  are  pressed  together 
the  membrane  may  be  seen  projecting  through  the  liga- 
mentous  covering  like  small  vesicles. 

The  wrist  joint  may  be  dislocated  either  by  the  radius 
and  ulna  being  both  thrown  forwards,  or  both  backwards : 
lateral  dislocations  seldom  occur,  and  are  always  partial. 
These  displacements  almost  always  occur  by  falls  on  the 
ground,  or  other  violence,  by  which  the  hand  is  forcibly 
bent  forwards  or  backwards,  on  the  bones  of  the  fore  arm; 
extensive  laceration  of  the  capsular,  anterior,  or  posterior 
ligaments,  and  considerable  synovial  effusion  and  swelling 
accompany  them.  The  tendons  also  of  the  flexor  and  ex- 
tensor muscles  are  more  or  less  displaced,  and  some  of 
them  may  be  ruptured.  The  form  of  the  arch  of  the  first 
range  of  carpal  bones  favours  the  dislocation  backwards, 
since  from  their  greater  convexity  in  this  direction,  they  do 
not  afford  as  much  support  to  the  bones  of  the  fore  arm. 

ARTICULATIONS  OF  THE  BONES  OF  THE  CARPUS. 

The  bones  of  the  carpus  are  arranged  in  two  rows,  three 
in  the  superior,  and  four  in  the  inferior,  between  these  rows 
a  certain  degree  of  motion  takes  place,  but  between  the  in- 
dividual bones  in  each  row  there  is  little  or  none.  The 
bones  of  the  first  row  are  the  scaphoid,  lunar,  and  cunei- 
form, these  are  connected  in  the  following  manner  : — 

First,  inler-osseous  ligaments  ;  these  are  short  and  compact 
dense  tissues,  placed  between  the  upper  borders  of  the  scap- 
hoid and  lunar,  and  lunar  and  cuneiform,  they  range  on  a 
level  with  the  carpal  convexity  of  these  bones,  and  are 
covered  by  the  synovial  membrane  of  the  carpus. 


511  DUBLIN    DISSECTOR. 

Second  and  third,  the  dorsal  and  palmar  ligaments  are  com- 

Eosed  of  strong  bands  which  pass  in  different  directions 
*om  one  bone  to  another. 

The  pisiform  bone,  which  is  the  smallest  bone  of  the 
carpus,  does  not  properly  belong  to  either  row,  it.  is  articu- 
lated to  the  fore  part  of  the  cuneiform  only  by  a  flat  sur- 
face, which  is  furnished  with  a  loose  synovial  membrane; 
two  strong  ligaments  also  connect  it,  one  to  the  cuneiform 
bone,  and  the  other  to  the  fifth  metacarpal  bone,  the  tendon 
of  the  flexor  carpi  ulnaris  and  the  muscles  of  the  little 
finger,  also  serve  to  retain  it  in  its  situation,  and  to  attach 
it  to  the  annular  ligament  and  palmar  fascia. 

The  four  bones  of  the  second  row  of  the  carpus,  like  those 
of  the  first,  are  connected  together  by  inter-osseous  sub- 
stance, and  by  dorsal  and  palmar  bands  which  run  in  every 
direction  ;  there  is  no  inter-osseous  substance  between  the 
trapezium  and  trapezoid.  The  second  row  is  articulated  to 
the  first  by  an  enarthrosis  in  the  centre,  and  an  arthrodia 
at  either  side  ;  the  central  joint  is  between  the  round  head 
of  the  magnum  and  the  cavity  of  the  scaphoid  and  lunar 
bones,  the  lateral  arthodire  are  between  the  scaphoid  and 
cuneiform  bones  above  and  the  trapezium,  the  trapezoid 
and  unciform  below.  These  two  rows  are  attached  by 
strong  lateral  and  by  anterior  and  posterior  ligaments,  the 
former  seem  continuations  of  the  lateral  ligaments,  of  the 
wrist,  the  latter  pass  from  the  circumference  of  one  row  to 
that  of  the  other,  the  aggregate  might  be  considered  as  a 
capsular  ligament. 

The  synovial  membrane  between  the  first  and  second  row 
is  very  loose  and  distinct,  and  may  be  considered  as  com- 
mon to  almost  all  the  joints  of  the  carpus  ;  it  lines  all  the 
inferior  surface  of  the  first  and  sends  two  processes  up- 
wards, one  at  either  side  of  the  lunar  bone  as  high  as  the 
inter-osseous  ligament,  from  the  first  row  it  is  reflected  on 
the  anterior  and  posterior  ligaments,  and  thence  to  the  sec- 
ond row,  and  is  very  distinct  on  the  magnum,  being  con- 
tinued round  its  neck ;  from  this  row  it  sends  down  three 
prolongations  between  the  four  bones  of  the  second  row, 
these  also  extend  beneath  these  to  line  the  articulations  be- 
tween the  carpus  and  four  of  the  metacarpal  bones,  and 
some  are  even  still  further  prolonged,  between  the  lateral 
articulating  surfaces  of  the  heads  of  the  second  and  third, 
and  fourth  and  fifth  metacarpal  bones ;  thus  this  synovial 
membrane  is  almost  common  to  all  the  carpal  and  meta- 
carpal articulations,  there  are  however  some  parts  excepted, 
thus  between  the  pisiform  and  cuneiform  there  is  a  distinct 
synovial  membrane,  another  also  between  the  trapezium 
and  the  metacarpal  bone  of  the  thumb,  and  also  one  be- 


DUBLIN    DISSECTOR.  515 

tween  the  third  and  fourth  metacarpal  bones.  The  con- 
tinuity of  this  one  synovial  membrane  through  so  many 
articulations,  and  its  contiguity  to  the  other  membranes  in 
this  region  are  well  exemplified  in  cases  of  synovial  inflam- 
mation or  disease  of  the  carpus.-  The  bones  of  the  carpus 
are  also  firmly  connected  to  each  other  by  the  annular  liga- 
menti  which  is  inserted  externally  into  the  trapezium  and 
scaphoid,  and  internally  into  the  cuneiform,  pisiform,  and 
unciform  bones. 

[On  the  back  of  the  wrist  is  the  ligamentum  corpi  dorsale,  which 
extends  from  the  outer  or  styloid  edge  of  the  radius,  to  the  inner  or 
styloid  edge  of  the  ulnar ;  it  is  divided  into  six  compartments  or 
canals  for  the  transmission  of  appropriate  tendons,  which  is  its  use, 
rather  than  to  bind  the  bones  together.] 

The  close  connexion  of  the  bones  of  the  carpus  and  the 
numerous  ligaments  spread  in  all  directions  over  the  back 
and  front  of  the  hand,  present  powerful  obstacles  to  com- 
plete dislocations  of  any  of  these  bones;  the  only  one  at 
all  likely  to  occur,  is  that  of  the  head  of  the  os  magnum 
backwards  from  the  depression  in  the  semi-lunar  and  scap- 
hoid bones ;  here  the  quantity  of  motion  is  greatest,  and 
the  joint  is  very  weak  and  loose  in  some  feeble  persons ; 
however  this  luxation  is  almost  invariably  incomplete. 

THE   ARTICULATIONS    BETWEEN    THE   CARPUS   AND  METACARPUS. 

THESE  joints  are  secured  before  and  behind  by  transverse 
and  oblique  fibrous  bands,  which  cover  the  synovial  mem- 
branes and  pass  in  different  directions :  the  synovial  mem- 
brane between  the  trapezium  and  the  metacarpal  bone  of 
the  thumb  is  distinct  from  the  rest,  and  possesses  a  capsu- 
lar  ligament,  the  pulley-like  surfaces  of  this  joint  admit  of 
very  free  motion,  adduction,  abduction,  flexion,  and  exten- 
sion, and  slight  rotation.  The  other  joints  are  also  furnished 
with  synovial  membranes,  which  are  prolonged  from  that 
between  the  first  and  the  second  row  of  the  carpus,  except 
in  the  case  of  the  third  and  fourth,  which  possess  a  distinct 
sac.  The  second  metacarpal  bone  is  articulated  to  the 
trapezium,  trapezoid,  magnum,  and  to  the  third  metacarpal 
bone;  the  third  to  the  magnum,  and  to  the  second  and 
fourth  metacarpal  bones  ;  the  fourth  to  the  magnum,  unci- 
form, and  to  the  third  and  fifth  metacarpal  bones  ;  the  fifth 
to  the  unciform  and  to  the  fourth  metacarpal  bone.  The 
anterior  or  lower  extremities  of  the  metacarpal  bones  are 
not  in  contact,  but  are  connected  by  a  strong  transverse 
band  of  ligamentous  fibres,  [the  transverse  or  inferior  palmar 
ligament.] 
Dislocations  of  the  metacarpal  bones  from  the  carpus 


516  DUBLIN    DISSECTOR, 

seldom  occur,  except  in  the  case  of  the  first  metacarpal 
bone,  which  may  be  dislocated  from  its  articulation  with 
the  trapezium  forwards  or  backwards ;  in  the  backward 
luxation  the  carpal  extremity  of  the  bone  is  driven  through 
the  posterior  part  of  the  capsular  ligament ;  the  lateral  liga- 
ments may  or  may  not  be  ruptured.  The  flexor  ossis  me- 
tacarpi,  and  flexor  brevis  and  longus,  with  the  adductor, 
offer  great  resistance  to  reduction  when  delayed  for  any 
time.  In  the  dislocation  forwards  the  metacarpal  bone  is 
thrown  between  the  trapezium  and  the  root  of  the  second 
metacarpal  bone ;  the  thumb  is  bent  back,  and  cannot  be 
flexed :  the  external  lateral  ligament  is  in  this  case  more 
likely  to  be  torn  than  in  the  former.  The  extensors  of  the 
thumb  are  the  muscles  which  offer  resistance  to  reduction 
of  this  dislocation. 

ARTICULATION   BETWEEN    THE   METACARPUS    AND   THE   PHA- 
LANGES. 

THESE  arthrodial  joints  are  furnished  with  capsular  lig- 
aments and  synovial  membranes ;  the  sockets  do  not  re- 
ceive the  entire  head  of  each  bone,  the  latter  being  much 
larger,  particularly  on  their  posterior  aspect ;  the  capsules 
are  weak  and  lax  behind,  strong  on  the  sides  like  distinct 
lateral  ligaments,  and  very  close  and  compact  in  front, 
often  with  somewhat  of  a  cartilaginous  structure ;  in  the 
thumb  this  ligament  lodges  the  sesamoid  tubercles,  in  this 
finger  also  this  articulation  differs  from  that  in  the  other 
fingers,  in  possessing  but  little  motion  in  any  direction  ex- 
cept that  of  flexion  and  extension,  whereas  the  others  pos- 
sess also  the  power  of  adduction,  abduction,  and  rotation ; 
these  articulations  are  much  strengthened  by  the  tendons 
of  the  flexors,  extensors,  lumbricales,  and  inter-ossei  mus- 
cles. 

The  ginglymoid  articulations  of  the  phalanges  are  se- 
cured by  synovial  membranes,  and  by  very  strong  lateral 
and  anterior  ligaments,  posteriorly  the  synovial  mem- 
branes are  only  partially  covered  by  the  extensor  tendons ; 
but  anteriorly  they  are  perfectly  protected  by  the  flexor 
tendons  and  their  sheaths. 

Tne  first  phalanx  of  the  thumb  is  the  only  joint  of  this 
series  very  liable  to  dislocation,  it  is  frequently  dislocated 
backwards,  from  the  head  of  the  metacarpai  bone.  The 
lateral  ligaments  remain  uninjured  and  become  very  tense. 
This  dislocation  is  interesting  from  the  great  difficulty  of 
reducing  it  when  neglected  even  for  a  short  time.  The 
phalanges  of  the  other  fingers  may  be  dislocated  either 
backwards  or  forwards,  these  accidents  are  obvious,  and 
when  recent  easily  admit  of  reduction. 


DUBLIN    DISSECTOR.  517 


ILIO-FEMORAL   ARTICULATION,  OR   HIP   JOINT. 

THIS  is  the  strongest  and  most  perfect  enarthrosis  in  the 
system,  it  includes  the  head  of  the  femur  and  the  acetabu- 
lum,  both  of  which  are  encrusted  with  cartilage,  and  is  se- 
cured by  a  capsular  and  an  accessory  ligament,  a  synovial 
membrane,  an  inter-articular,  cotyloid,  and  a  transverse 
ligament :  the  cartilage  on  the  head  of  the  femur  is  de- 
ficient a  little  below  its  centre,  as  also  that  of  the  acetabu- 
lum  in  a  space  extending  from  the  notch  to  its  centre,  the 
former  lodges  the  insertion  of  the  inter-articular  ligament, 
the  latter  a  mass  of  articular  fat. 

The  capsular  ligament  is  the  strongest  in  the  body,  it  has 
some  analogy  to  that  of  the  shoulder  joint,  but  is  not  so 
loose,  neither  are  the  surrounding  tendons  so  identified  with 
it ;  there  is  a  large  bursa  on  its  anterior  surface,  between 
it  and  the  tendon  of  the  psoas,  in  some  rare  cases  this  com- 
municates with  the  cavity  of  the  joint ;  another  bursa  is 
placed  more  externally  ;  between  the  great  trochanter  and 
the  tendon  of  the  glutaeus  maximus,  there  are  also  several 
large  bursse  connected  to  the  surrounding  tendons. 

The  capsular  ligament  arises  from  the  dorsum  of  the 
acetabulum,  encloses  the  cotyloid  ligament  as  it  ascends, 
but  does  not  adhere  to  it  except  at  the  notch,  it  is  also  con- 
nected to  the  inferior  spine  of  the  ilium,  and  to  the  obtu- 
rator ligament,  it  is  inserted  into  the  base  of  the  neck  of  the 
femur  ;  being  longer  behind  and  below  than  in  any  other 
situation,  it  is  weaker  behind  and  below  than  above  or  be- 
fore ;  at  the  lower  and  internal  part  it  is  so  thin  in  chil- 
dren, and  the  fibres  so  scattered,  that  the  synovial  mem- 
brane can  be  seen  through  it ;  the  fibres  of  this  ligament 
take  different  directions,  the  superficial  are  long  and  ver- 
tical. 

[This  ligament  includes  the  neck  of  the  femur  to  such  an  extent, 
that  a  fracture  of  the  neck  within  the  capsular  ligament  can  and 
does  take  place,  usually  however  in  old  subjects.  The  ligament  in. 
eludes  the  neck  more  completely  anteriorly,  where  it  extends  as  far 
as  to  the  anterior  intertrochanteric  line,  whereas  posteriorly  the  liga- 
ment is  lost  upon  the  periosteum  several  lines  within  the  posterior  in- 
tertrochanle:ic  line.] 

Accessory  or  ilio-femoral  ligament  is  a  strong  fibrous  band, 
incorporated  with  the  capsular,  arising  from  the  inferior 
spinous  process  of  the  ilium,  it  descends  obliquely  inwards, 
becomes  broader,  and  is  inserted  near  the  lesser  trochanter, 
this  strengthens  the  capsule  anteriorly,  and  opposes  the 
head  of  the  femur  in  extension  of  the  thigh.  These  exter- 
nal ligaments  derive  additional  strength  from  the  surround- 
ing muscles,  viz.  anteriorly,  from  the  psoas,  iliacus,  and 
44 


518  DUBLIN    DISSECTOR. 

rectus ;  externally  or  superiorly  from  the  glutaeus  minimus, 
which  adheres  closely  to  the  capsule  ;  posteriorly  from  the 
quadratus  femoris,  pyriformis,  gemelli  and  obturator  in- 
terrms,  and  internally  from  the  obturator  externus  and 
pectinasus. 

The  synovia!  membrane  is  exposed  by  dividing  the  capsu- 
lar  ligament,  whose  internal  surface  it  lines  to  a  great 
extent,  it  is  continued  from  the  head  of  the  femur  around 
the  neck  near  to  its  baser  but  not  so  far  as  the  fibrous  cap- 
sule ;  on  the  neck  it  is  loose  in  some  parts,  and  thrown  into 
little  folds  or  wrinkles  which  adhere  to  strong  fibrous 
bands,  thickened  portions  of  periosteum,  which  extend 
from  the  head  along  the  neck  to  the  capsular  ligament ; 
from  the  neck  the  synovial  membrane  is  reflected  to  the 
capsule,  along  which  it  is  conducted  to  the  outer  circum- 
ference of  the  acetabulum,  it  then  covers  both  surfaces  of 
the  cotyloid  ligament,  lines  the  acetabulum,  adheres  to  the 
fatty  mass  at  the  bottom  of  this  cavity,  and  is  then  reflect- 
ed along  the  inter-articular  ligament  to  the  head  of  the 
femur.  The  articular  fatty  mass  has  a  peculiar  reddish 
appearance,  it  fills  the  rough  surface  in  the  acetabulum, 
and  is  confined  in  its  place  by  a  number  of  decussating 
tendinous  bands,  it  receives  a  great  number  of  blood  ves- 
sels and  nerves  chiefly  from  the  obturator  ;  there  are  also 
red  fatty  masses  around  the  neck  of  the  femur,  and  one  at 
the  insertion  of  the  inter-articular  ligament  in  the  head  of 
the  bone. 

The  cotyloid  ligament  may  be  next  noticed,  this  is  the 
fibro-cartilaginous  lip  which  deepens  the  acetabulum,  and 
at  the  same  time  narrows  its  orifice,  so  as  to  hold  or  retain 
the  head  of  the  femur  even  after  the  capsular  ligament  and 
all  the  muscles  have  been  divided  ;  it  is  composed  of  strong 
circular  fibres,  these  pass  in  deeper  in  those  particular 
situations  where  the  acetabulum  in  infancy  was  separable 
into  three  parts;  it  serves  to  deepen  the  cavity,  and  to 
prevent  the  neck  of  the  femur  striking  against  the  sharp 
edge  of  the  cavity. 

Transverse  ligament  consists  of  ligamentous  bands,  which 
pass  across  the  notch  in  the  border  of  the  acetabulum, 
some  pass  from  the  pubis  to  the  ischium,  others  decussate 
these  and  pass  from  ischium  to  pubis;  it  completes  the 
margin  of  the  cavity  and  leaves  sufficient  space  above  it 
for  the  passage  of  vessels  and  nerves. 

Inter-articular  ligament,  or  ligamentum  teres,  is  about  an 
inch  and  a  half  in  length,  it  consists  of  fine  ligamentous 
fibres  covered  rather  loosely  by  synovial  membrane; 
though  called  round,  it  is  rather  of  a  triangular  form,  the 
base  attached  to  the  notch  and  to  the  depression  in  the  ace- 


DUBLIN    DISSECTOR.  519 

tabulum,  the  apex  to  the  head  of  the  femur ;  it  arises  by 
two  flat  bands,  the  superior  of  which  is  the  smaller,  from 
the  margins  of  the  cotyloid  notch,  these  soon  unite  being 
enveloped  by  the  synovial  membrane,  the  ligament  then 
runs  upwards,  backwards  and  outwards,  contracting  in  size, 
between  the  articular  fatty  mass  and  the  head  of  the  bone, 
into  the  depression  on  which  it  is  inserted. 

[This  ligament  is  frequently  described  incorrectly.  By  one  ex- 
tremity it  is  attached  to  the  depression  on  the  head  of  the  femur,  to- 
wards the  other  it  divides  into  two  roots  ;  of  which  one  may  be  traced 
around  the  lower  edge  of  the  cotyloid  notch,  until  it  is  finally  lost 
upon  the  face  of  the  ischium,  between  its  tuberosity  and  the  edge  of 
the  acetabulum  ;  the  other  root  may  be  traced  to  the  upper  end  of  the 
notch,  where  it  is  lost  near  the  edge  of  the  acetabulum  ;  hence  this 
ligament  is  not  necessarily  torn  off  in  the  dislocation  of  the  femur, 
into  the  obturator  foramen,  for  in  this  displacement  the  two  extremi- 
ties of  the  ligament  are  approximated.] 

This  ligament  is  very  rarely  wanting,  it  serves  to  conduct 
blood-vessels  from  the  acetabulum  to  the  head  and  neck  of 
the  femur,  which  from  its  position  in  respect  to  the  shaft  of 
the  bone,  may  require  a  nutritious  supply  from  this  source ; 
some  consider  it  may  also  limit  too  much  abduction  of  the 
thigh.  This  joint  enjoys  free  motion  in  every  direction, 
flexion,  extension,  abduction.,  adduction,  rotation  and  cir- 
cumduction  ;  the  depth  of  the  acetabulum,  the  strength  of 
its  capsular  ligament,  together  with  the  surrounding  mus- 
cles, all  seem  well  adapted  to  prevent  luxation,  such  acci- 
dents, however,  not  unfrequently  occur. 

This  joint  is  not  so  liable  to  dislocation  as  that  of  the 
shoulder  for  several  reasons  ;  in  the  first  place,  its  motions 
are  much  more  limited  both  in  number  and  extent;  second, 
the  glenoid  cavity  affords  little  mechanical  security,  while 
the  cotyloid  on  the  contrary  permits  the  head  of  the  femur 
to  sink  into  it ;  third,  the  oblique  direction  also  of  the  head 
of  the  thigh  bone  presents  an  additional  obstacle ;  fourth, 
the  capsular  ligament  of  this  joint  is  much  stronger  and 
shorter  than  that  of  the  shoulder,  and  it  is  further  protect- 
ed by  very  strong  accessory  fibres  on  the  outer  and  upper 
part,  which  descend  from  the  inferior  anterior  spine  of  the 
ilium,  and  by  some  on  the  inner  side  from  the  superior  part 
of  the  foramen  ovale. 

The  joint  of  the  hip  may  be  dislocated  in  four  ways, 
backwards  and  upwards  on  the  dorsum  of  the  ilium,  back- 
wards on  the  ischiatic  notch,  forwards  and  upwards  on  the 
pubes,  and  forwards  and  downwards  on  the  foramen  obtu- 
ratorium. 

[One  case  has  occurred  of  a  dislocation  of  the  femur  into  the  peri- 
neum; this  was  probably  a  secondary  displacement,  supervening  upon 


520  DUBLIN    DISSECTOR. 

a  primary  dislocation  into  the  obturator  foramen.  This  case  has 
never  been  published,  but  the  minutes  of  it,  are  in  the  possession  of 
Dr.  Parker,  Prof,  of  Surgery  in  the  college.] 

The  situation  of  the  trochanter  major  is  a  point  of  great 
importance  in  discriminating  accidents  about  the  hip  joint, 
and  its  relation  to  some  other  prominent  points  should  be 
well  kept  in  mind ;  in  the  erect  position  of  the  body,  the 
superior  part  of  the  trochanter  major  is  nearly  on  the  same 
level  with  the  body  of  the  pubes,  the  distance  between  the 
anterior  superior  spine  of  the  ilium  and  the  trochanter  ma- 
jor is  less  than  from  this  projection  to  the  o.s  pubis,  or  from 
the  os  pubis  to  the  anterior  superior  spine,  lines  connect- 
ing these  three  points  will  form  nearly  a  right  angled  tri- 
angle, of  which  the  longest  side  is  the  line  connecting  the 
superior  spine  to  the  pubis,  and  the  shortest,  that  which 
joins  the  spine  to  the  trochanter.  In  dislocation  upwards 
or  backwards  the  trochanter  is  brought  nearer  the  superior 
anterior  spine  of  the  ilium,  but  is  much  less  prominent 
than  natural :  in  the  luxation  backward  it  is  removed  from 
the  body  of  the  pubis,  and  is  also  less  prominent  than  na- 
tural :  in  the  dislocation  into  the  obturator  foramen,  the 
distance  between  the  trochanter  major  and  the  body  of  the 
pubis  is  lessened,  while  that  between  this  process  and  the 
anterior  superior  spine  is  greater  than  usual. 

In  dislocation  upwards  and  backwards,  which  is  by  far 
the  most  frequent,  the  head  of  the  bone  rests  on  the  dorsum 
of  the  ilium,  the  upper  part  of  the  capsular  ligament  is 
ruptured,  and  the  accessory  and  round  ligaments  are  torn: 
the  limb  is  shortened  about  two  inches,  and  is  inverted  and 
almost  fixed.  In  rotation  inwards  the  head  of  the  femur  is 
pressed  against  the  back  part  of  the  capsular  ligament, 
and  if  the  rotation  be  carried  far,  a  considerable  portion  of 
the  bone  is  outside  the  cotyloid  cavity  :  hence  the  species 
of  dislocation  now  described  is  most  likely  to  occur  when 
rotation  inwards  is  accompanied  by  external  violence,  that 
is  by  the  individual  foiling  or  receiving  a  blow  when  the 
knee  and  foot  are  turned  inwards.  When  this  dislocation 
has  occurred  the  three  glutsei  muscles  are  those  principally 
concerned  in  keeping  the  head  of  the  bone  fixed  on  the 
dorsum  of  the  ilium;  but  when  the  limb  has  been  extend- 
ed and  the  head  of  the  bone  is  sufficiently  raised  to  pass 
over  the  edge  of  the  acetabulum,  the  psoas  and  iliacus  with 
the  obturator  externus  and  pectinalis,  will  assist  to  bring 
it  into  the  proper  situation.  Although  in  common  cases  of 
dislocation  we  may  presume,  from  the  rapid  recovery  of 
the  patient,  that  no  other  injury  is  done  to  the  joint  than 
what  has  been  already  described,  yet  the  dissection  of  a  case 
of  luxation  upwards 'and  backwards  has  been  published, 


DUBLIN    DISSECTOR.  521 

in  which  the  gemelli,  pyriformis,  obturators,  and  quadratus 
femoris,  were  completely  tore  across,  with  laceration  of 
some  fibres  of  the  pectinalis 

In  the  dislocation  backwards,  and  which  is  also  a  little 
upwards,  or  that  into  the  ischiatic  notch,  the  head  of  the 
bone  rests  on  the  pyriformis  muscle  and  between  it  and  the 
sciatic  ligaments,  the  limb  is  a  little  shortened,  it  is  also 
inverted,  but  much  less  so  than  in  the  dislocation  on  the 
dorsum  of  the  ilium.  This  dislocation  also  is  most  likely 
to  happen  when  the  thigh  is  rotated  inwards  and  bent  to 
wards  the  abdomen. 

When  the  femur  is  dislocated  forwards  on  the  obturator 
foramen,  the  capsuiar  ligament  and  the  internal  accessory 
fibres  are  lacerated.  The  ligamentum  teres  is,  according 
to  Sir  A.  Cooper,  always  ruptured :  the  limb  is  lengthened 
about  two  inches,  the  knee  advanced  and  abducted  with 
slight  eversion,  the  great  troehanter  is  much  less  prominent 
than  usual. 

In  dislocation  upwards  and  forwards  the  head  of  the  bone 
rests  on  the  ramus  of  the  pubis  under  Poupart's  ligament, 
where  it  may  be  plainly  felt;  the  limb  is  shortened,  slightly 
flexed,  and  everted. 

A  calculation  has  been  made,  that  out  of  twenty  disloca- 
tions of  the  hip  joint,  twelve  will  take  place  on  the  dorsum 
ilii,  five  on  the  ischiatic  notch,  two  on  the  foramen  ovale, 
and  one  on  the  pubis. 

FEMORO-TIBIAL    ARTICULATION,    OR    THE   KNEE-JOINT. 

THE  condyles  of  the  femur,  the  head  of  the  tibia,  and 
the  patella,  enter  into  this  arthroidal  ginglymoid  articula- 
tion, the  fibula  is  only  remotely  connected  with  it.  The 
ligaments  which  secure  it  may  be  classed  into  those  exter- 
nal and  those  internal  to  the  synovial  membrane,  although 
strictly  they  are  all  internal  to  it ;  the  external  ligaments 
are,  the  ligamentum  patellae,  ligamentum  posticum,  and  the 
internal  and  external  lateral  ligaments.  Several  bursa:  are 
in  its  vicinity,  three  are  placed  on  its  anterior  aspect,  these 
may  be  named  the  superior,  middle,  and  inferior;  the 
first  and  last  are  deep  seated,  the  second  is  cutaneous,  being 
placed  on  the  patella,  and  partially  covered  by  an  imper- 
fect fascia,  its  cavity  is  frequently  intersected  by  tendinous 
bands.  The  superior  bursa  is  placed  on  the  forepart  of  the 
femur,  behind  the  extensor  tendons  and  surrounded  by  fat, 
it  is  very  thin  and  almost  always  communicates  with  the 
cavity  of  the  joint,  it  often  appears  as  the  prolonged  synovial 
membrane  of  the  joint  itself.  The  inferior  bursa  is  small 
and  delicate,  is  situated  between  the  tubercle  of  the  tibia 
and  the  ligament  of  the  patella,  there  are  various  other 

44* 


522  DUBLIN    DISSECTOR. 

small  bursse  connected  to  the  adjacent  tendons.  Although 
there  is  no  regular  capsular  ligament  to  this  joint,  yet  its 
place  is  in  a  great  degree  supplied  by  the  fascia  lata  and 
by  the  aponeu roses  from  the  lateral  muscles,  tendons  and 
ligaments,  which  give  it  a  very  perfect  covering.  The 
bony  surfaces  which  compose  this  joint  have  been  already 
described,  these  are  covered  in  the  usual  way  with  a  com- 
pact cartilage ;  on  the  femur  this  extends  much  higher  on 
the  condyles  in  front  and  behind,  and  does  not  at  all  cover 
their  sides ;  on  the  tibia  it  is  thicker  in  the  centre  than  at 
the  circumference,  contrary  to  the  general  condition  in  ar- 
throdial  surfaces ;  this  apparent  anomaly,  however,  is  re- 
moved by  attending  to  the  position  of  the  semi-lunar  car- 
tilages, which  deepen  the  border  of  these  cavities  so  con- 
siderably. 

The  ligamentum  patella,  consists  of  strong,  parallel,  glis- 
tening, tendinous  fibres,  which  descend  obliquely  outwards 
and  backwards  from  the  inferior  angle  of  the  patella,  and 
are  inserted  into  the  tubercle  of  the  tibia,  a  little  below  the 
small  bursa  which  lies  behind  this  ligament ;  it  is  partly 
a  continuation  of  the  extensor  tendon  in  which  the  patel- 
la was  developed  at  first  in  the  form  of  cartilage,  in  the 
same  manner  as  the  sesamoid  bones  are  ;  this  ligament  is 
about  two  inches  long,  and  narrower  in  the  centre  than  at 
either  end,  it  is  covered  by  the  skin  and  fascia  lata,  and  it 
lies  upon  a  quantity  of  soft  adeps  and  upon  the  small  infe- 
rior bursa. 

The  posterior  ligament  [or  ligament  of  Winslow],  has  been 
noticed  in  the  dissection  of  the  semi-membranosus  muscle 
from  the  tendon  of  which  this  quadrilateral  ligament  arises; 
it  then  ascends  obliquely  from  behind  the  inner  condyle  of 
the  tibia  to  the  external  condyle  of  the  femur,  it  separates 
the  gastrocnemii  and  plantaris  from  the  synovi;il  membrane 
to  which  it  adheres,  it  is  made  very  tense  and  resisting  in 
extension  of  the  leg,  in  flexion  it  is  relaxed  and  drawn  a 
little  backwards,  and  in  this  state  the  synovial  membrane 
is  drawn  out  of  the  angle  of  the  joint  in  consequence  of  its 
attachment  to  this  aponeurosis.  (See  page  262.) 

The  internal  lateral  ligament  is  flat  and  broader  in  the 
centre  than  at  either  end,  it  arises  from  the  internal  condyle 
of  the  femiar,  descends  obliquely  forwards,  and  is  inserted 
into  the  internal  condyle  of  the  tibia,  and  into  the  semi- 
lun-ar  cartilage ;  this  i'igamsnt  is  closely  applied  to  the 
synovial  membrane  and  to  the  semilunar  cartilage,  the 
tendon  of  the  serni-membranosus  and  some  articular  ves- 
sels separate  it  near  its  insertion  from  the  tibia,  it  is  covered 
by  the  aponeurotic  expansion  of  the  gracilis,  sartorius,  and 
semi-tendinosus. 


DUBLIN    DISSECTOR.  523 

The  external  lateral  ligament  or  ligaments  arise  from  the 
external  condyle,  above  the  fossa  for  the  poplitaeal  tendon, 
are  thick,  round  and  short,  descend  backwards,  and  are 
inserted  into  the  head  of  the  fibula ;  a  portion  of  the  biceps 
tendon  sometimes  separates  these  ligaments ;  in  many  cases 
they  form  but  a  single  cord ;  when  there  are  two,  the  long 
one  is  superficial;  the  external  lateral  ligament  has  little 
or  no  connexion  to  the  synovial  membrane,  being  separated 
from  it  by  the  poplitseus  tendon,  the  articular  vessels,  and 
a  portion  of  the  biceps  tendon ;  a  portion  of  the  short  or 
deep  ligament  is  commonly  found  connected  to  the  semi- 
lunar  cartilage. 

The  external  and  internal  lateral  ligaments  are  situated 
a  little  behind  the  centre  of  the  articulation,  hence  they 
become  relaxed  in  flexion  and  tense  in  extension  of  the 
limb,  they  serve  to  connect  the  several  bones  together,  to 
confine  the  semi-lunar  cartilages  in  their  places,  and  to 
prevent  any  lateral  displacement,  they  also  resist  rotation 
of  the  femur  on  the  tibia  inwards,  but  admit  of  rotation 
outwards,  whereas  they  admit  of  the  tibia  or  the  leg  rota- 
ting inwards  but  not  outwards  ;  the  ligamentum  patella?, 
the  internal  and  external  lateral  ligaments  favour  rotation 
of  the  tibia  inwards  and  oppose  it  outwards.  To  see  the 
internal  ligaments,  separate  the  extensor  tendons  from  the 
patella,  and  open  the  synovial  membrane  above  and  behind 
the  latter. 

The  synovial  membrane  of  the  knee  is  the  largest  mem- 
brane of  this  class  in  the  body;  from  the  lower  extremity 
of  the  extensor  tendon  it  passes  back  to  the  forepart  of  the 
femur  a  little  above  the  condyles,  it  rises  higher  above  the 
outer  than  the  inner  of  these  processes  ;  where  the  bursa 
and  synovial  membrane  communicate  freely  they  appear 
but  one  membrane  rising  on  the  femur  to  a  height  of  two 
or  three  inches  above  the  eondyle  ;  it  is  continued  over  the 
condyles,  and  covers  their  sides  although  they  are  deficient 
of  cartilaginous  incrustation,  it  ascends  higher  on  the  inter- 
nal side  of  the  inner  condyle  than  of  the  outer,  posteriorly 
it  is  also  continued  above  the  inner  to  a  greater  height  than 
above  the  outer ;  from  the  back  part  of  the  femur  it  is  re- 
flected on  the  head  of  the  gastrocnemii  on  each  side,  and 
on  the  posterior  ligament  in  the  centre  ;  from  the  depres- 
sion between  the  condyles,  but  rather  from  the  external,  a 
fold  of  this  membrane  descends  obliquely  forwards  and  in- 
wards to  the  mass  of  articular  fat  at  the  lower  and  anterior 
part  of  the  joint,  this  is  termed  the  ligamentum  mucosum  ; 
it  is  also  continued  from  the  femur  along  the  crucial  liga- 
ments to  the  head  of  the  tibia;  from  the  lateral  parts  of 
the  joint  this  membrane  is  continued  to  the  upper  surface 


524  DUBLIN    DISSECTOR. 

of  the  semi-lunar  cartilages,  on  which  it  spreads,  it  then 
turns  round  their  sharp,  thin  edge  to  their  lower  surface, 
and  thence  to  the  upper  surface  of  the  tibia,  where  it  meets 
the  reflections  which  have  descended  along  the  crucial 
ligaments  ;  from  the  tibia  it  is  continued  anteriorly  to  the 
mass  of  soft  adeps,  which  it  covers,  and  where  it  joins  the 
ligamentum  mucosum,  it  then  passes  to  the  posterior  and 
upper  part  of  the  ligamentum  patellae,  and  lastly  it  covers 
the  back  part  of  the  patella  at  the  upper  border  of  which 
we  commenced  its  description  :  as  the  popliteal  tendon  is 
continued  from  the  outer  condyle,  a  process  of  this  mem- 
brane is  reflected  round  three-fourths  of  it,  as  far  as  the 
head  of  the  fibula,  where  this  process  touches  the  synovial 
membrane  of  the  tibio-peronseal  articulation,  and  in  some 
instances  the  synovial  membranes  of  these  two  articula- 
tions, though  very  generally  distinct,  communicate. 

The  internal  ligaments  in  this  joint  are,  the  alar,  mucous, 
transverse,  crucial,  and  the  semi-lunar  cartilages. 

The  alar  ligaments  are  only  folds  of  the  synovial  mem- 
brane, in  some  measure  produced  by  the  displacement  of 
the  patella,  they  are  one  on  either  side  of  this  bone,  they 
diverge  above  and  uniting  below  are  lost  in  the  fatty  mass ; 
the  internal  is  the  most  distinct. 

The  ligamentum  mucosum  is  also  a  small  fold  of  the  same 
membrane,  passing  from  the  fatty  substance  behind  the 
ligamentum  patellae,  backwards,  upwards  and  a  little  out- 
wards to  the  hollow  between  the  condyles  ;  it  serves  to  re- 
gulate the  position  of  the  fat,  to  keep  it  opposite  the  notch 
of  the  femur,  and  thus  preserve  a  more  even  surface. 

The  transverse  ligament  extends  between  and  is  attached 
to  the  anterior  convex  portions  of  the  two  semilunar  car- 
tilages, and  above  the  fatty  substance  before  alluded  to ; 
it  serves  to  retain  the  adipose  mass  in  its  situation,  and  to 
prevent  its  receding  into  the  cavity  of  the  joint,  it  also  in 
some  measure  secures  the  semilunar  cartilages  in  their  pro- 
per situation. 

The  crucial  ligaments  are  the  most  important  of  the 
inter-articular  ligaments,  they  are  two  strong,  shining, 
twisted,  fibrous  cords,  which  pass  from  the  notch  in  the 
femur  to  the  median  line  of  the  head  of  the  tibia,  they  are 
very  close  to  each  other  about  the  centre  of  the  joint,  but 
thence  they  separate,  crossing  each  other  as  they  pass  to 
their  respective  attachments :  when  viewed  anteriorly  or 
posteriorly  this  decussation  resembles  the  letter  X,  they 
cross  also  in  the  lateral  view ;  to  see  the  ligaments  distinct- 
ly the  patella  must  be  thrown  completely  down,  the  liga- 
mentum mucosum  divided,  also  the  lateral  and  posterior 
ligaments,  and  the  synovial  membrane  dissected  from  these 


DUBLIN    DISSECTOR.  525 

fibrous  cords,  for  although  they  appear  within  the  cavity 
of  the  joint,  they  are  really  without  and  behind  it,  and  in 
the  latter  aspect^  the  membrane  can  easily  be  detached 
from  them  at  its  reflection  without  its  cavity  being  opened. 

The  anterior,  or  horizontal,  or  external  crucial  ligament  ari- 
ses from  the  inner  and  posterior  part  of  the  external  con- 
dyle,  descends  obliquely  forwards  and  inwards,  and  is  in- 
serted near  the  forepart  of  the  head  of  the  tibia,  where  it 
also  joins  the  anterior  cornu  of  the  internal  somilunar  car- 
tilage ;  this  ligament  is  best  seen  when  the  joint  is  flexed. 

The  posterior,  or  internal  or  perpendicular  crucial  ligament 
arises  from  the  outer  and  forepart  of  the  internal  condyle, 
descends  nearly  vertical,  and  is  inserted  partly  into  the  ex- 
ternal semilunar  cartilage,  and  partly  into  the  depression 
on  the  back  of  the  tibia  behind  its  median  spine  :  this  liga- 
ment is  larger  than  the  anterior,  its  origin  is  seen  anterior- 
ly behind  the  ligamentum  mucosum,  its  insertion  is  broad, 
and  is  best  seen  posteriorly,  when  the  joint  is  extended 
and  the  ligament  of  Winslow  and  a  quantity  of  fat  removed. 

The  crucial  ligaments  serve  to  attach  the  femur  to  the 
tibia,  they  steady  the  one  bone  upon  the  other,  and 
strengthen  the  back  part  of  the  joint  in  the  same  manner 
as  the  patella  does  in  front,  they  also  tend  to  prevent  any 
lateral  displacement ;  they  are  both  made  tense,  and  of 
course  prevent  too  much  rotation  of  the  tibia  inwards,  and 
they  are  relaxed  and  separate,  somewhat  in  rotation  out- 
wards ;  in  extension  also  they  are  both  very  tense,  espe- 
cially the  posterior,  in  flexion  the  anterior  is  so,  but  in  a 
less  degree  ;  in  fine  they  resist  too  great  rotation  inwards, 
also  excessive  extension  or  flexion,  but  they  admit  of  rota- 
tion outwards  ;  the  posterior  ligament  also,  by  its  attach- 
ment to  the  external  semilunar  cartilage,  serves  to  retain 
or  restore  this  cartilage  to  its  place,  as  in  rotation  of  the 
leg  outwards  the  cartilage  is  allowed  to  yield  or  move 
backwards.  If  the  crucial  ligamonts  be  divided  the  femur 
may  be  detached,  and  the  twisted  structure  of  the  former 
can  be  seen.  The  semilunar  cartilages  and  their  ligaments 
may  be  next  examined. 

The  semilunar  cartilages  are  placed  upon  the  articular  sur- 
faces of  the  tibia ;  the  convex  margin  of  each  is  thick  and 
connected  by  its  edges  to  the  synovial  membrane,  arid  be- 
tween these  to  the  external  ligaments  and  fascia,  this  latter 
aponeurotic  attachment  has  been  called  the  coronary  liga- 
ment of  each  cartilage;  the  internal  concave  margin  has 
a  sharp  edge,  which  is  loose  in  the  cavity  of  the  joint : 
each  cartilage  presents  above  an  excavated  surface  adapted 
to  the  condyles,  and  below  a  flat  surface  adapted  to  the 
head  of  the  tibia.  The  anterior  and  posterior  extremities 


526  DUBLIN    DISSECTOR. 

of  each  are  fibrous  and  fixed  to  the  head  of  the  tibia,  be- 
fore and  behind  its  middle  protuberance,  these  insertions 
are  termed  the  oblique  ligaments.  The  two  cartilages  are 
united  in  front  by  the  transverse  ligament;  the  external 
cartilage  is  more  circular,  and  more  moveable  than  the  in- 
ternal, which  is  a  segment  of  an  oval  figure  ;  the  anterior 
extremity  of  the  internal  is  connected  to  the  anterior  cru- 
cial ligament,  while  the  posterior  crucial  is  attached  to  the 
external  cartilage.  The  median  line  of  the  tibia  presents 
the  insertion  of  these  several  parts  in  the  following  order, 
from  before  backwards  ;  first,  is  the  anterior  cornu  of  the 
internal  semilunar  cartilage ;  second,  the  insertion  of  the 
anterior  crucial  ligament ;  thirdly,  the  anterior  cornu  of  the 
external  cartilage,  the  insertion  of  the  anterior  crucial  li- 

fament  is  intimately  connected  to  the  anterior  cornua  of 
oth  cartilages,  particularly  of  the  internal ;  fourthly,  the 
posterior  cornu  of  the  external  cartilage,  only  separated 
from  its  anterior  by  a  portion  of  the  insertion  of  the  ante- 
rior crucial  ligament ;  fifthly,  the  posterior  cornu  of  the 
internal  cartilage  ;  and  sixthly,  the  insertion  of  the  poste- 
rior crucial  ligament.  The  semilunar  cartilages  serve  to 
deepen  the  articular  surfaces  of  the  tibia,  and  thus  to  re- 
tain the  condyles  of  the  femur,  the  mobility  of  the  external 
one  also  favours  rotation  of  the  leg  and  thigh  outwards,  in 
the  latter  motion  the  outer  condyle  of  the  femur  glides  a 
little  backwards,  the  condyle  of  the  tibia  being  bevelled 
off  posteriorly,  the  external  cartilage  is  enabled  to  ac- 
company the  femur,  and  thus  to  secure  and  facilitate  its 
motion. 

Dislocation  of  the  patella  may  take  place  either  up- 
wards, inwards,  or  outwards,  the  latter  is  the  more  frequent 
form  ;  a  dislocation  upwards  could  not  occur  without  rup- 
ture of  the  inferior  ligament  of  the  patella,  which  is  so 
strong  that  frequently  in  violent  action  of  the  extensor 
muscles,  the  patella  itself  snaps  across  before  this  ligament 
gives  way.  When  the  knee  is  much  bent  dislocation  in 
either  direction  cannot  take  place.  The  extent  of  the  ar- 
ticulating surfaces  of  the  femur,  and  the  force  with  which 
the  patella  is  pressed  in  between  the  condyles,  prevents 
such  an  accident.  The  position  most  favourable  to  this 
luxation  is  where  the  knee  is  slightly  bent  and  inclined  in- 
wards. When  complete  luxation  of  the  patella  outwards 
has  taken  place,  the  patella  rests  over  the  external  condyle 
of  the  femur,  in  which  place  it  is  fixed  by  the  rectus,  cru- 
reus,  and  vasti  muscles ;  hence  the  necessity  for  bending 
the  thigh  on  the  pelvis,  in  order  to  relax  these  muscles  as 
much  as  possible.  The  extent  of  the  synovial  membrane 
permits  this  displacement  to  occur  without  any  rupture. 


DUBLIN    DISSECTOR.  527 

Dislocation  of  the  patella  inwards  is  so  similar  in  its  na- 
ture to  the  outward  luxation  that  it  does  not  require  any 
notice. 

The  tibia  may  be  dislocated  from  the  femur  in  four  di- 
rections, backwards,  forwards,  or  to  either  side,  the  two 
former,  particularly  that  backwards,  may  be  complete,  the 
latter  are  incomplete.  There  is  no  joint  in  the  body  so  well 
supported  by  ligaments  as  that  of  the  knee ;  on  the  sides 
we  have  the  lateral  ligaments  ;  in  front  the  ligament  of  the 
patella  and  the  tendinous  insertion  of  the  extensor  muscles; 
behind  the  posterior  ligament  of  Winslow  ;  and  more  par- 
ticularly the  strong  crucial  ligaments.  Additional  liga- 
mentous  bands  are  also  occasionally  seen.  When  the  tibia 
is  completely  dislocated  backwards  into  the  ham,  the  liga- 
mentous  attachments  of  the  patella  either  above  or  below 
must  give  way,  and  the  leg  is  shortened.  The  crucial  and 
posterior  ligaments  are  also  torn.  The  flexor  muscles  of 
the  leg,  which  are  attached  to  the  tibia,  will  contribute  to 
keep  the  bone  in  the  luxated  position.  Complete  forward 
dislocations  of  the  tibia  have  occurred,  but  they  are  very 
rare  ;  in  such  case  all  the  ligaments  of  the  joint  must  give 
way,  and  the  heads  of  the  gastrocnemii  and  popliteus  mus- 
cles would  also  probably  suffer. 

The  semilunar  cartilages  are  sometimes  displaced,  par- 
ticularly the  internal  one,  it  usually  arises  from  a  sudden 
twist  of  the  knee  inwards,  and  in  persons  whose  knee  joints 
are  distended  from  frequent  injury  or  chronic  rheumatism ; 
but  little  is  known  of  the  true  pathology  of  this  injury 

SUPERIOR   TIBIO-FIBULAR   ARTICULATION. 

THIS  is  a  very  plane  arthrodia,  the  surface  of  the  tibia 
being  slightly  convex,  to  meet  the  head  of  the  fibula.  The 
tibio-fibular  articulations  can  scarcely  admit  of  any  com- 
parison with  the  radio-ulnar,  though  analogous  to  them  in 
position,  but  little  motion  occurring  in  the  former,  arid  very 
free  motion  in  the  latter.  This  articulation  is  secured  by  a 
distinct  synovial  membrane,  which,  as  has  been  before 
mentioned,  sometimes  communicates  with  that  of  the  knee 
joint ;  there  is  also  a  distinct  anterior  and  posterior  [tibia 
fibular~\  ligament,  each  composed  of  strong  fibres  passing 
from  one  bone  to  the  other  ;  the  external  lateral  ligament 
and  the  tendon  of  the  biceps  still  further  secure  this  joint ; 
in  which  the  fibula  enjoys  a  very  obvious  motion  forwards, 
backwards,  and  a  little  upwards ;  this  latter,  though  to  a 
small  extent,  yet  permits  the  outer  ankle,  and,  of  course, 
the  whole  foot  to  move  more  freely  outwards. 

Luxation  of  the  upper  head  of  the  fibula  is  usually  the 


528  DUBLIN    DISSECTOR. 

consequence  of  disease  ;  for  the  application  of  a  force  suf- 
ficient to  dislocate  the  bone  is  much  more  likely  to  break 
it.  The  action  of  the  biceps  flexor,  the  only  muscle  in- 
serted into  the  fibula,  could  not  alone  produce  this  accident. 
When  the  head  of  the  fibula  is  thrown  back,  the  anterior 
ligament  and  the  accessory  fibres  from  the  tendon  of  the 
biceps,  with  the  synovial  capsule,  are  ruptured.  Boyer 
mentions  a  case  in  which  the  whole  fibula  was  driven  di- 
rectly upwards  in  consequence  of  a  dislocation  outwards 
of  the  ankle. 

The  shafts  of  these  two  bones  are  connected  by  the  inter- 
osseous  membrane,  which  consists  of  aponeurotic  fibres 
descending  obliquely  from  the  tibia  to  the  fibula  ;  they  are 
deficient  above  and  below,  the  tibialis  anticus  and  the  ex- 
tensors of  the  foot  cover  it  in  front,  and  the  flexors  behind. 

INFERIOR   TIBIO-FIBULAR   ARTICULATION. 

THE  inferior  extremity  of  the  fibula  is  received  into  a  de- 
pression in  the  tibia,  and  connected  to  it  by  a  strong  ante- 
rior and  posterior  ligament,  which  are  each  of  a  triangular 
form,  the  base  below  attached  to  the  fibula,  also  by  a  small 
portion  of  the  synovial  membrane  continued  from  that  of 
the  ankle  joint,  and  above  this  by  an  inter-osseous,  dense, 
fibrous  substance  :  some  fibres  of  the  posterior  ligament 
extend  from  one  malleolus  to  the  other,  strengthen  the  ankle 
joint,  and  assist  in  forming  the  socket  for  the  astragalus, 
very  little  motion  occurs  in  this  joint,  beyond  a  little  yield- 
ing or  shuffling  of  one  surface  against  the  other. 

ARTICULATION   OF   THE   ANKLE. 

THIS  is  the  most  perfect  ginglymoid  joint  in  the  body,  ex- 
cepting that  between  the  ulna  and  humerus,  a  deep  mortise- 
like  cavity  is  formed  by  the  lower  surface  of  the  tibia  and 
by  the  two  malleoli,  the  latter  deepened  the  cavity  consid- 
erably at  each  side,  the  tibio-fibular  ligaments  also,  par- 
ticularly the  posterior,  complete  the  margins  before  and 
behind ;  the  tibia  is  the  principal  bone  in  this  cavity,  the 
fibula  forms  little  more  than  its  outer  wall,  this,  however, 
though  narrow,  passes  down  very  low  and  affords  it  con- 
siderable defence  in  this  aspect ;  the  internal  malleolus  is 
not  so  long  or  deep,  but  is  broader,  and  extends  more  for- 
wards than  the  outer  ankle,  hence  the  foot  inclines  out- 
wards more  freely  than  inwards :  this  joint  is  secured  by 
very  strong  lateral  ligaments,  and  also  by  a  synovial  mem- 
brane, and  an  anterior  ligament. 

The  internal  lateral  or  deltoid  ligament  is  very  dense,  it 
arises  from  the  internal  malleolus,  descends  in  a  radiated 


DUBLIN    DISSECTOR.  529 

manner,  and  is  inserted  into  the  astragalus,  os  naviculare, 
and  calcis ;  the  posterior  fibres  are  short  and  thick,  the  an- 
terior are  long  and  thin  :  in  flexion  the  posterior  fibres  are 
tense,  in  extension  the  anterior  ;  this  ligament  is  close  to 
the  synovial  membrane  of  the  joint,  and  has  equally  closely 
connected  to  it  the  synovial  and  tendinous  sheaths  of  the 
tibialis  posticus,  and  of  the  flexor  tendons  which  wind 
around  it,  and  which  give  additional  strength  to  this  region 
of  the  joint. 

The  external  lateral  ligaments  are  three,  a  posterior,  middle, 
and  anterior ;  they  all  arise  from  the  external  malleolus ; 
the  posterior  is  very  strong  and  tense,  passes  obliquely 
backwards  and  inwards  to  the  ridge  an  the  back  of  the  as- 
tragalus, which  separates  the  ankle  joint  from  the  articula- 
tion of  the  astragalus  to  the  os  calcis;  its  superior  border 
is  continued  some  way  on  the  synovial  membrane  of  the 
ankle  to  the  tibia  ;  it  not  only  secures  the  ankle  articula- 
tion, but  it  also  binds  the  fibula  inwards  towards  the  tibia, 
it  is  not  much  altered  by  the  motions  of  the  joint ;  the  mid- 
dle is  round,  descends  almost  vertically  but  a  little  back- 
wards, and  is  inserted  into  the  os  calcis  ;  it  is  supported  by 
the  peronseal  tendons  ;  the  anterior  is  inserted  into  the  upper 
and  outer  part  of  the  astragalus. 

The  anterior  ligament  of  the  ankle  is  often  indistinct ;  it 
arises  from  the  anterior  edge  of  the  tibia,  and  is  inserted  into 
the  upper  and  outer  part  of  the  astragalus. 

The  synovial  membrane  is  large  and  loose  before  and 
behind,  ft  always  contains  some  fluid,  it  lines  the  anterior 
surface  of  the  tibia  and  of  the  two  rnalleoli,  and  ascends  a 
little  way  between  the  tibia  and  fibula,  it  covers  the  supe- 
rior and  lateral  articular  surfaces  of  the  astragalus,  and  is 
prolonged  a  little  way  on  the  upper  surface  of  its  neck,  it 
is  looser  anteriorly  than  in  any  other  direction,  to  admit  of 
more  free  extension.  Almost  the  only  motions  in  this  joint 
are  flexion  and  extension,  the  latter  is  more  free  than  the 
former,  both  can  be  carried  to  a  considerable  extent,  but 
particularly  extension,  an  excess  of  either  motion  is  resisted 
by  the  opposed  bony  edges  coming  into  contact,  and  by  the 
tension  of  the  tendons  and  ligaments;  when  the  joint  is 
flexed,  as  when  we  stand  in  the  erect  posture,  or  when  it  is 
even  more  flexed,  as  when  we  bend  the  body  forward  there 
is  scarcely  any  lateral  motion  whatever,  but  when  the 
nnkle  joint  is  extended,  even  to  a  slight  degree,  as  in  walk- 
ing, the  head  of  the  astragalus  being  less  locked  in  the 
socket,  a  slight,  lateral  motion  can  occur  to  either  side,  but 
chiefly  to  the  outer,  in  consequence  of  the  outer  malleolus 
being  on  a  posterior  plane  to  the  internal :  ir.  this  outward 
lateral  motion,  the  fibula  recedes  a  little  at.ii  rises  vertU 
45 


530  DUBLIN    DISSECTOR. 

cally ;  this  latter  motion  is  of  great  use,  and  is  obvious 
if  the  superior  articular  heud  of  the  bone  be  examined  at 
the  time. 

This  lateral  or  slight  rotatory  motion  at  the  ankle  joint, 
is  not  to  be  confounded  with  the  general  abduction  and  ad 
duction  enjoyed  by  the  different  articulations  in  the  tarsus, 
particularly  at  that  between  the  astragalus  and  navicular 
bones  :  these  motions,  though  different  from,  yet  materially 
add  to  that  which  has  been  just  alluded  to  in  the  ankle  joint 
itself. 

The  ankle  joint  is  the  frequent  seat  of  injury  ;  the  lower 
extremity  of  the  fibula  is  very  liable  to  fracture,  and  the 
tibia  to  luxation,-  complete  or  incomplete  ;  when  any  such 
accidents  occurs  the  foot  suffers  proportional  deformity  and 
displacement.  Such  displacements  ought,  in  conformity  to 
the  language  applied  to  the  corresponding  injuries  in  other 
joints, to  be  denominated  luxations  of  the  foot,  whereas  wri- 
ters usually  notice  th<3  upper  bone  or  bones  engaged  in  the 
injury.  Thus  the  tibia  is  described  as  liable  to  partial  or 
perfect  dislocation  inwards,  outwards,  forwards,  and  back- 
wards ;  it  might  be  more  correct  to  describe  each  of  these 
injuries  as  perfect  or  imperfect  dislocations  of  the  foot  out- 
wards, inwards,  backwards,  and  forwards.  When  the  tibia 
is  luxated  internally,  which  is  by  far  the  most  frequent  acci- 
dent in  this  region,  and  which  is  almost  always  accompa- 
nied with  and  indeed  in  a  great  measure  the  consequence 
of  a  fracture  of  the  lower  end  of  the  fibula,  the  interna. 
malleolus  projects  on  the  inner  side  of  the  astragalus  and 
os  calcis,-  the  outer  side  of  the  foot  and  malleolus  look  up- 
wards, and  the  sole  of  the  foot  is  directed  somewhat  out- 
wards, so  that  the  leg  has  no  longer  its  proper  bearing  on 
the  foot,  the  axis  of  the  former  inclining  inwards,  whilst 
the  foot  is  twisted  outwards;  the  synovial  membrane  is 
ruptured,  and  in  many  cases  there  is  laceration  of  the  del- 
toid and  anterior  ligaments  of  the  tibia,  and  of  the  poste- 
rior transverse  band  from  the  tibia  to  the  fibula.  After  the 
accident  has  taken  place,  the  contraction  of  the  gastrocne- 
mii,  solsei,  and  especially  of  the  peronei  muscles,  which 
rotate  the  foot  outwards,  and  ^.raw  it  upwards,  sometimes 
offer  much  resistance  to  reduction ;  this,  however,  is  usu- 
ally overcome  by  placing  these  muscles  in  a  relaxed  po- 
sition. 

If  the  tibia  be  dislocated  onwards,  the  astragalus  is  forced 
outwards  below  the  external  malleolus,  which  latter  pro- 
jects considerably,  the  foot  is  turned  inwards,  the  sole  look- 
ing upwards  and  the  internal  malleolus  is  sunk  in  a  deep 
hollow :  in  this  accident  the  malleolus  internes  must  be 
broken  off  obliquely,  the  deltoid  ligament  is  not  ruptured, 


DUBLIN    DISSECTOR.  531 

the  fibula  is  usually  broken,  but  if  not,  the  external  la- 
teral, anterior,  and  posterior  ligaments  of  this  bone  are 
lacerated. 

In  the  dislocation  forwards,  the  fibula  and  malleolus  in- 
ternus  are  broken,  the  tibia  rests  on  the  anterior  part  of 
the  astragalus  and  on  the  os  naviculare  ;  the  posterior  part 
of  the  deltoid  ligament,  and  the  transverse  band  from  the 
tibia  to  the  fibula  are  ruptured  ;  dislocation  forwards  is  an 
accident  of  rare  occurrence,  it  cannot  happen  when  the 
foot  is  flexed  on  the  tibia,  for  then  the  tibia  sinks  down  on 
the  back  part  of  the  astragalus,  and  nothing  but  consider- 
able force  could  raise  it  over  the  upper  portion  of  the  bone, 
which,  in  this  position,  extends  like  a  bridge  before  it ;  it 
can  only  occur  when  the  ankle  is  forcibly  and  suddenly 
extended,  in  this  luxation  the  foot  is  lengthened  behind, 
and  shortened  in  front,  and  presents  a  considerable  projec- 
tion in  the  latter  situation,  caused  by  tije  tibia  and  the  se- 
veral tendons  it  supports. 

Luxation  backwards  is  even  still  more  rare.  Were  such 
an  accident  to  take  place,  all  the  tibial  ligaments  would  be 
broken,  and  the  fibula  most  probably  fractured.  There  is 
no  accurate  account  of  a  well  authenticated  case  of  this 
accident  on  record,  indeed  it  is  difficult  even  to  .conceive 
how  it  could  possibly  occur. 

ARTICUTATIONS  OF  THE  BONES  OF  THE  TARSUS. 

THE  seven  bones  of  the  tarsus  are  connected  in  such  a 
close  and  firm  manner  as  to  admit  of  but  little  motion  be- 
tween any  two,  except  at  the  articulation  between  the  as- 
tragalus and  the  scaphoid,  which  is  somewhat  analogous  to 
that  of  the  os  magnum  in  the  carpus. 

ARTICULATIONS    OF    THE    ASTRAGALUS. 

THE  astragalus  rests  on  the  os  calcis  by  two  arthrodial 
surfaces,  the  posterior  is  concave,  external,  and  larger  than 
the  anterior  or  internal,  which  is  convex ;  a  deep  groove, 
leading  forwards  and  outwards,  separates  these  two  joints. 
These  two  bones  are  connected  by  a  strong  inter-osseous 
substance,  which  arises  from  the  groove  in  the  astragalus 
between  the  two  articular  surfaces,  and  is  inserted  into  that 
on  the  os  calcis  ;  there  are  also  two  synovial  membranes, 
the  posterior  is  confined  to  these  two" bones,  but  the  ante- 
rior is  continuous  with  the  synovial  membrane,  between 
the  astragalus  and  the  scaphoid  ;  these  synovial  membranes 
are  strengthened  by  strong  accessory  bands  on  either  side  ; 
the  lateral  ligaments  of  the  ankle  joint  also  serve  to  attach 
these  bones  more  closely. 


532  DUBLIN    DISSECTOR. 

The  anterior  end  or  the  head  of  the  astragalus,  is  receiv- 
ed into  the  concave  surface  of  the  scaphoid  bone,  which, 
together  with  the  strong  fibro-cartilaginous  calcaneo-scap- 
hoid  ligament,  and  a  small  portion  of  the  os  calcis,  com- 
pletes the  socket  for  the  astragalus.  This  joint  approaches 
to  the  class  of  enarthrosis,  and  possesses  very  free  motion 
on  which  the  mobility  of  the  tarsus  and  toes  greatly  de- 
pends ;  it  is  furnished  with  a  synovial  membrane,  which  is 
covered  superiorly  by  strong  but  short  tendinous  fibres, 
and  below  by  the  calcaneo  scaphoid  ligament,  which  extends 
from  the  anterior  inferior  part  of  the  os  calcis  to  the  lower 
surface  of  the  scaphoid,  it  supports  the  head  of  the  astra 
galus,  and  is  itself  much  strengthened  by  the  tendon  of  the 
tibialis  posticus  which  winds  round  beneath  it ;  this  tendon 
also,  or  this  ligament  usually  contains  a  sesamoid  tubercle 
or  a  sort  of  cartilaginous  patella  in  this  place ;  this  liga- 
ment supports  the«great  weight  of  the  body,  while  its  elas- 
ticity lessens  the  effects  of  those  concussions  to  which  the 
body  is  subject  in  the  many  violent  exercises  in  which  it 
is  engaged  :  the  synovial  membrane  of  this  joint  is  contin- 
uous with  that  on  the  anterior  and  inferior  surface  of  the 
astragalus. 

Simple  as  well  as  compound  dislocations  not  unfrequent- 
ly  occur  in  this  articulation,  the  head  of  the  astragalus 
being  usually  thrown  forwards  so  as  to  form  a  prominence 
on  the  instep :  the  reduction  is  in  general  attended  with  great 
difficulty,  and  in  some  cases  is  found  impracticable :  in 
some  instances  the  bone  has  been  completely  turned  round, 
«o  that  its  lower  concave  surface  has  held  a  firm  hold  of 
the  end  of  the  tibia. 

[It  is  sometimes  impossible  to  reduce  a  dislocated  astragalus,  and 
it  has  been  extirpated  on  this  account  by  Dr.  Alex.  H.  Stevens, 
where  the  dislocation  was  attended  with  an  external  wound.] 

ARTICULATIONS   OF    THE   SCAPHOID  BONE. 

THE  scaphoid  bone  is  articulated  to  all  the  tarsal  bones ; 
by  direct  apposition,  to  the  astragalus  behind,  to  the  three 
cuneiform  bones  before,  and  to  the  cuboid  externally,  and 
indirectly  to  the  os  calcis  by  the  strong  inferior  calcaneo- 
scaphoid  ligament  just  described. 

ARTICULATIONS   OF   THE    CUBOID   BONE. 

THE  cuboid  is  articulated  with  the  os  calcis  behind,  with 
the  fifth  and  fourth  meta tarsal  bones  before,  and  internally 
with  the  scaphoid  and  external  cuneiform  bones ;  the  ar- 
throdial  surfaces  of  the  cuboid  and  os  calcis  are  connected 
fcy  very  distinct  ligaments  both  on  the  dorsum  and  on 


DUBLIN    DISSECTOR.  533 

the  sole  of  the  foot.  The  calcaneo-cubpid  and  astragalo- 
scaphoid  articulations  are  on  a  transverse  level,  the  line 
of  which  is  occasionally  selected  for  amputation  in  diseases 
of  the  toes.  The  superior  or  dorsal  calcaneo-cuboid  ligaments 
are  broad  but  short,  are  close  to  the  synovial  membrane,, 
and  are  covered  by  the  tendon  of  the  peronoeus  tertius. 

The  inferior  calcaneo-cuboid  ligaments  are  very  distinct; 
they  are  long  but  thick,  and  can  be  divided  into  lamina, 
they  are  of  a  bright  shining  appearance,  they  arise  from 
the  under  surface  of  the  os  calcis,  pass  forwards,  and  are 
inserted  into  the  cuboid  bone,  into  the  sheath  for  the  long 
peroriseal  tendon,  and  into  the  base  of  the  third  and  fourth 
metatarsal  bones.  The  cuboid  is  connected  to  the  scaphoid 
and  to  the  external  cuneiform  bones  by  synovial  mem- 
branes,  by  dorsal  and  plantar  ligaments,  and  by  short, 
strong,  inter-osseous  fibres ;  sometimes  there  is  no  synovial 
membrane  between  it  and  the  scaphoid  bone. 

ARTICULATIONS    OF   THE   CUNEIFORM   BONES. 

THE  three  arthrodial  articulations  between  the  cuneiform 
bones  and  the  scaphoid  are  secured  by  a  synovial  mem- 
brane  which  is  common  to  all,  and  by  strong  dorsal  and 
plantar  ligamentous  bands. 

Dislocations  of  any  of  the  other  articulations  of  the  tar- 
sus are  very  rare,  except  in  very  severe  accidents,  and 
where  complicated  injuries  are  inflicted  on  the  foot ;  cases 
however  are  on  record  of  simple  dislocation  of  the  cuboid 
bone  from  the  os  calcis;  also  of  the  internal  cuneiform 
bone  being  separated  from  the  navicular  in  a  direction  up- 
wards and  inwards. 

TARSO-METATARSAL    ARTICULATIONS. 

THE  three  internal  metatarsal  bones  are  joined  to  the 
three  cuneiform,  and  the  fourth  and  fifth  metatarsal  to  the 
cuboid.  The  tar  so- metatarsal  articular  range  presents  a 
slightly  waving  line,  as  the  second  metatarsal  bone  extends 
further  back  than  the  others.  But  little  motion  exists  in 
any  of  these  plain  arthrodial  articulations,  they  are  fur- 
nished with  synovial  membranes  and  transverse  dorsal  and 
plantar  bands.  The  first  metatarsal  and  the  internal  cunei- 
form possess  a  distinct  synovial  membrane,  the  second 
metatarsal  is  furnished  with  a  synovial  membrane,  which 
is  common  to  it  and  to  the  three  cuneiform  bones  :  another 
connects  the  third  metatarsal  and  third  cuneiform  bones, 
and  the  adjacent  metatarsal  surfaces;  and  the  two  last 
metatarsal  bones  and  the  cuboid  are  also  furnished  with  a 
distinct  synovial  membrane  ;  on  the  whole  these  articula- 

45* 


534  DUBLIN    DISSECTOR. 

tions  resemble  those  of  the  metacarpal  bones  in  all 
tial  circumstances. 

The  anterior  end  of  each  metatarsal  bone  is  connected 
to  the  first  phalanx  of  each  toe,  and  the  phalanges  of  all 
the  toes  are  articulated  to  each  other  by  synovial  membranes 
and  by  lateral  ligaments  as  are  those  of  the  fingers,  and 
therefore  they  do  not  require  any  elaborate  or  distinct  des- 
cription. 

The  phalanges  of  the  toes  are  but  rarely  dislocated  either 
from  each  other  or  from  the  metatarsal  bones ;  the  most 
frequent  accident  of  this  class,  is  a  dislocation  of  the  first 
phalanx  of  the  great  toe  from  the  metatarsal  bone. 


THK    END. 


APPENDIX. 


DIRECTIONS   FOR   MAKING   DRIED  PREPARATIONS   OF   THE 
ARTERIES   AND   VEINS. 

f Furnished  to  the  Publishers  by  a  Medical  Gentleman.] 

ALTHOUGH  in  every  anatomical  school  competent  persons  are  re- 
tained  for  the  purpose  of  injecting  arteries  and  veins;  still  the  stu- 
dent may  wish  to  do  it  for  himself,  or  he  may  be  placed  in  such  situa- 
tions that  he  cannot  command  any  kind  of  assistance  :  to  him,  more 
particularly,  the  few  remarks  which  we  purpose  making  on  the 
method  of  injecting  and  of  preserving  arterial  preparations,  may  be 
considered  applicable. 

Injections  are  of  two  kinds,  coarse  and  fine  ;  there  are  many  de- 
scriptions of  coarse  injections  ;  with  the  fine  we  have  nothing  to  do, 
as  it  is  used  by  anatomists  only  for  the  purpose  of  imitating  the  natu- 
ral vascularity  which  membranes  and  other  structures  lose  aftei1 
death.  Coarse  injections  may  be  employed  either  hot  or  cold,  for- 
merly the  hoi  injection  was  the  only  one  used,  but  now  the  cold  one 
is  very  frequently  employed.  As  much  of  the  success  of  the  injec- 
tion depends  on  the  state  of  the  subject,  great  care  should  be  observ- 
ed in  the  choice  ;  if  possible  a  young  and  thin  one  should  always  be 
employed,  as  the  arteries  in  old  subjects  are  so  often  ossified  and  in- 
elastic, that  we  can  never  be  certain  that  they  will  not  burst  from 
the  force  employed,  and  extravasate  the  injection  between  the  mus- 
cles and  into  the  different  cavities  ;  another  objection  to  the  use  of 
old  subjects  is,  that  the  constant  oozing  of  oily  matter  from  prepara. 
tions  made  of  them  renders  them  filthy,  and  almost  useless,  particu- 
larly in  warm  weather;  however,  some  old  subjects  may  be  filled 
With  the  cold  (or  paint)  injection,  if  care  be  taken  not  to  use  too 
much  force.  When  the  student  has  made  up  his  mind  to  employ 
the  hot  injection,  it  may  be  useful  to  him  to  follow  a  few  rules.  In 
the  first  place,  the  pipe  should  be  tied  so  firmly  in  the  opening  into 
the  vessel,  that  there  will  be  no  possibility  of  its  slipping  out ;  se- 
condly, the  nozzle  of  the  syringe  should  always  be  introduced  into 
the  pipe,  for  the  purpose  of  exhausting  the  artery  of  air  or  coagulated 
blood  ;  this  being  done,  the  stopcock  should  be  immediately  turned  ; 
and  lastly,  particular  care  should  be  taken  that  the  syringe,  pipe,  and 
stopcock  are  free  and  in  good  order. 

To  inject  with  the  hot  injection,  it  is  necessary  that  the  subject 
should  be  thoroughly  heated  ;  this  is  best  done  by  opening  the  cavitie* 
of  the  thorax  and  abdomen,  and  filling  them  with  water  of  a  tem- 
perature that  the  hand  can  bear ;  the  body  at  the  same  time  should 


536  APPENDIX. 

be  immersed  in  water  of  the  same  temperature,  taking  care  to  exclude 
atmospheric  air  as  much  as  possible.  The  process  of  heating  should 
be  carried  on  until  the  subject  has  acquired  a  temperature  resembling 
the  natural  heat  of  the  living  body.  While  this  is  going  on,  the  in- 
jection should  be  particularly  attended  to,  as  the  materials  are  very 
inflammable,  and  if  care  be  not  taken,  or  much  heat  be  employed, 
there  will  be  danger  of  burning  the  chimney  or  house ;  heat,  slowly 
applied,  will  melt  the  injection  without  any  admixture  of  air,  or  en 
tlangering  the  loss  of  colour,  which  strong  heat  would  certainly  effect. 

[The  better  plan  is  to  melt  the  injection,  by  placing  the  materials 
in  an  earthen  vessel  and  then  putting  this  vessel  into  a  water  bath  ; 
by  this  method  the  materials  are  perfectly  melted  and  equally  heat, 
ed  without  danger  of  boiling  or  burning.  It  is;also  better  not  to  stir 
in  the  coloring  matter  until  the  injection  is  thoroughly  melted,  and 
about  to  be  used  ;  for  some  of  the  colouring  substances  are  apt  to 
cake  or  form  lumps  in  the  injection  if  subjected  to  too  much  heat. 
For  immediate  demonstration  chrome  yellow  is  a  good  coloring  sub- 
stance  for  arterial  injection,  because  it  offers  a  greater  contrast  to 
the  color  of  the  muscles  than  vermilion  :  as  the  putrefactive  process 
goes  on,  however,  it  is  apt  to  turn  black  ;  this  is  also  an  objection  to 
red  lead.  In  making  arterial  preparations  this  objection  is  obviated 
by  pencilling  the  vessels  over  with  vermilion  paint  after  they  are  per- 
fectly dry. — Amer.  Ed.] 

When  the  subject  and  injection  are  sufficiently  heated,  the  injec- 
tion should  be  sucked  up  twice  or  thrice,  so  as  to  mix  it  well  with 
the  coloring  matter,  which  always  falls  to  the  bottom  :  before  the 
syringe  is  introduced  into  the  pipe,  it  should  be  held  up  and  the  pis- 
ton pressed  lill  the  injection  appears,  by  which  any  air  that  may  be 
in  the  syringe  will  be  permitted  to  escape,;  taking  the  wings  of  the 
pipe  into  the  left  hand,  the  syringe  is  to  be  introduced,  and  the  pis- 
ton is  to  be  pushed  down  slowly  and  gradually  with  the  right  hand, 
until  the  syringe  is  emptied  ;  this  action  is  to  be  repeated,  till  we  feel 
resistance  made  to  the  further  passage  of  the  fluid  in  the  arteries:  if 
after  this  resistance  is  felt,  any  further  force  be  used,  there  will  be 
great  danger  of  rupturing  the  arteries  and  producing  extravasation. 
As  soon  as  we  are  satisfied  that  the  body  is  injected,  it  should  be  put 
in  cold  water,  where  it  should  remain  for  a  few  hours.  Either  of  the 
following  hot  injections  may  be  used : 

Wax  f  xvi. 

Resin  f  viii. 

Turpentine  Varnish  f  viii. 

Chinese  Vermilion  f  i. 

This  makes  a  very  handsome  injection,  but  it  is  liable  to  the  in- 
convenience of  melting  in  warm  weather,  and  in  this  way  producing 
a  flattened  appearance  in  the  blood  vessels.  A  much  cheaper  and 
better  injection  for  common  purposes  than  the  above  has  been  em- 
ployed ;  it  is  made  of — 

Tallow  21bs. 

Magnesia  Usta  f  ss. 

Chinese  Vermilion  Ji. 


APPENDIX.  537 

This  possesses  all  the  advantages  of  the  wax  injection  withou: 
any  of  its  inconveniences ;  it  is  as  transparent  nearly  as  the  wa*{, 
never  melts  in  the  hottest  weather,  and  is  not  disposed  to  crack ;  if 
this  injection  be  used  very  hot,  an  extremity  may  be  injected  with 
out  having  been  previously  heated  ;  but  tin's  should  never  be  do;.e 
except  by  persons  skilled  in  the  art  of  jnjecting. 

If  \ve  wish  to  trace  the  minute  branches  of  arteries  and  examine 
the  various  communications,  there  are  no  injections  better  adapted 
.or  common  purposes  than  that  of  tallow  and  red  led  well  mi,xed  and 
heated,  or  the  cold  paint  injection;  if  the  latter  be  well  thrown  in. 
the  minutest  arteries,  for  instance  the  ciliary,  will  be  injected  ;  it  is 
made  of — 

White  Lead,  well  ground,  21bs. 

Turpentine  Varnish  f  xii. 

Drying  Oil  ^vi. 

The  lead  is  intimately  mixed  with  the  varnish,  and  then  the  oil  ,a 
to  be  added  ;  they  are  all  to  be  well  mixed  up  together,  to  the  con. 
sistence  of  cream,  and  in  this  state  it  is  to  be  thrown  into  the  arte- 
ries :  the  same  precautions,  with  regard  to  the  exclusion  of  air  fro-a 
the  syringe,  and  the  degree  of  force  to  be  used,  are  to  be  observed  ir 
this  as  well  as  in  the  hot  injection.  Arteries  are  always  injected  fron. 
the  aorta  or  some  other  large  trunk;  while  veins  are  injected  diffe- 
rently :  in  making  preparations  of  veins,  it  is  necessary  to  inject  them 
from  the  extreme  branches  towards  the  trunks,  on  account  of  the 
direction  of  the  valves  :  for  instance,  the  veins  of  the  arm  are  to  be 
injected  from  a  small  branch  on  the  back  of  the  hand,  and  those  of 
the  leg  and  thigh  from  some  branch  on  the  dorsum  of  the  foot.  Pre- 
viously to  the  injection  being  made,  it  is  necessary  that  the  veins 
should  be  well  washed  out  with  warm  water,  to  remove  the  coagula 
of  blood  which  they  generally  contain  :  if  the  veins  of  the  arm  are 
to  be  injected,  an  opening  should  be  made  on  the  subclavian  vein,  to 
allow  the  warm  water  and  coagula  to  pass  out ;  when  this  has  hap- 
pened, a  ligature  previously  applied,  is  to  be  firmly  tied  round  the 
vessel,  which  will  prevent  the  injection  from  flowing  out ;  the  same 
rule  applies  to  the  injection  of  veins  in  the  lower  extremity.  The 
veins  of  the  head  and  neck  are  generally  injected  from  the  superior 
longitudinal  sinus  :  it  is  scarcely  necessary  to  mention  that  veins  are 
filled  with  blue  fluid,  and  the  arteries  with  white  or  red  ;  for  the  blue 
injection  smalt  blue  is  usually  employed.  To  inject  the  arteries  a 
transverse  cut  is  to  be  made  in  the  aorta,  as  close  to  its  origin  from 
the  heart  as  possible.  Care  must  be  taken  that  the  extremity  of  the 
pipe  does  not  project  so  far  as  to  pass  into  the  innominata,  or  one 
of  the  vessels  arising  from  the  left  side  of  the  arch,  as  this  would 
give  only  a  partial  injection.  The  nozzle  of  the  pipe  being  carefully 
inserted  into  the  opening  of  the  vessel,  two  pieces  of  twine  are  to  be, 
introduced  under  the  vessel ;  one  of  these  is  to  be  firmly  tied  round 
the  artery,  this  will  embrace  the  nozzle  of  the  pipe  ;  its  loose  extre- 
mities, when  the  knot  is  firmly  tied,  are  to  be  fixed  to  the  wings  ot 
the  pipe  in  order  to  prevent  any  chance  of  its  slipping  out  of  the  ves. 
sel.  The  other  ligature  is  to  remain  loose  under  the  vessel,  beyond 
the  nozzle  of  the  pipe  about  one  inch.  After  the  injection  is  thrown 
in,  this  ligature  is  also  to  be  firmly  tied  round  the  vessel,  leaving  thf 


538  APPENDIX. 

pipe  clear ;  the  use  of  it  is,  that  the  injection  may  not  return  back 
when  the  pipe  is  removed  from  the  aorta.  This  precaution  is  more 
particularly  necessary  when  the  paint  injection  is  used.  In  inserting 
a  pipe  into  a  small  artery  or  vein,  some  difficulty  may  arise  in  the 
introduction,  from  the  pipe  being  larger  than  the  calibre  of  the  ves- 
sel ;  in  this  case  the  point  of  a  scissors  should  be  introduced  into  the 
vessel,  and  gradual  dilatation  produced  by  slowly  opening  its  blades. 
When  the  injection  has  remained  sufficiently  long  to  set  well  in  the 
vessels,  dissection  may  be  commenced,  and  here  it  is  a  rule  which 
should  be  invariably  followed,  that  the  dissection  be  completed  in  as 
short,  a  time  as  is  consistent  with  a  proper  display  of  the  vessels,  for 
many  preparations  are  lost  in  consequence  of  the  part  first  dissected 
becoming  spoiled  before  the  remainder  is  prepared  for  drying.  Par- 
ticular care  should  be  taken  to  remove  all  the  cellular  substance 
from  the  coats  of  the  vessels  ;  if  this  be  not  done,  the  preparation 
will  always  have  a  dirty  appearance.  The  fatty  mutter  is  likewise 
to  be  removed,  but  no  muscle  is  to  be  taken  away  or  pushed  frona 
its  situation  unless  perfectly  unavoidable.  The  student  should  al- 
ways remember  that  the  utility  of  a  dried  preparation  consists  in  its 
preserving,  as  far  as  possible,  the  natural  relations  of  parts  :  on  this 
account,  the  use  of  pieces  of  stick  or  other  substances  to  separate 
the  muscles  and  exhibit  the  course  of  the  vessels,  unless  absolutely 
necessary,  is  to  be  condemned.  One  side  of  the  subject  ought  to  be 
appropriated  to  the  exhibition  of  the  superficial  vessels,  the  other  may 
be  used  for  the  deep-seated.  When  the  dissection  is  completed,  the 
extremity,  or  whatever  portion  of  the  body  it  may  be,  should  be 
hung  up  in  a  dry  and  airy  situation  (but  not  exposed  to  the  sun)  un- 
til the  muscles  acquire  firmness,  and  no  exudation  appears  on  the 
surface.  The  preparation  now  fit  for  use,  is  to  be  brushed  over  with 
copal  or  mastich  varnish,  which  makes  the  vessels  more  distinct,  and 
materially  assists  in  its  future  preservation. 

[Students  in  the  country  need  never  be  at  a  loss  for  an  injecting 
apparatus ;  the  common  anal  syringe  will  answer  the  purpose,  by 
casting  a  pewter  pipe,  on  a  wooden  or  paper  mould  ;  one  end  of  which 
pipe  shall  fit  the  nozzle  of  the  syringe,  and  the  other  go  into  the  ar- 
tery. It  is  better  to  use  a  syringe  whic'i  will  hold  about  the  quan- 
tity which  it  is  intended  to  throw  in.  A  very  convenient  point  from 
which  to  inject  is  the  femoral  artery,  just  below  Poupart's  ligament 
and  above  the  profunda.  When  injecting  the  veins,  it  is  convenient 
to  inject  the  large  trunks  from  the  femoral,  and  then  to  throw  in  in- 
jection from  the  extremities.  The  veins  which  form  the  portal  sys- 
tem may  be  injected  from  the  vena  porta  just  before  it  enters  the 
transverse  fissure  of  the  liver;  these  veins  not  being  obstructed  by 
valves,  the  injection  will  reach  the  mucous  membrane  of  the  intes- 
tines, as  low  as  the  anus  ;  the  better  plan  is  to  throw  in  first  spirits  of 
turpentine,  colored  with  lamp  black,  and  on  top  of  this  the  hard  injec- 
tion ;  by  this  method  the  whole  mucous  membrane  may  be  colored 
by  the  injection.  In  making  dry  preparations,  the  parts,  as  dissected, 
should  be  repeatedly  washed  over  with  a  solution  of  arsenic  or  of  cor- 
rosive sublimate  ;  this  hardens  the  tissues,  and  is  an  effectual  preser- 
vative against  insects  ;  the  preparations  also  present  a  solid  appear- 


APPENDIX.  539 

ance.  For  the  purpose  of  preserving  subjects  during  a  long  dissec- 
tion, a  solution  of  creosote  in  alcohol,  of  corrosive  sublimate  in  the 
same,  or  of  arsenic  in  boiling  water,  may  be  thrown  into  the  vessels 
twenty-four  or  forty-eight  hours  before  the  permanent  injection. 
These  solutions  percolate  through  the  tissues,  condense  them,  and 
preserve  them  effectually,  even  in  warm  weather,  particularly  the 
arsenic.  An  injection  always  accessible  in  the  country,  is  composed 
of —  Yellow  beeswax,  1  Ib. 

Tallow,  fxii. 

Resin,  f  viii. 

Vermilion,  or  chrome  yellow,  q.  s. 

This  injection  is  easily  prepared,  and  is  sufficiently  hard  for  dry 
preparations.  The  Annydrous  plaster  of  Paris  makes  a  very  neat  and 
minute  cold  injection.  The  colouring  matter  should  be  well  stirred 
in  with  the  plaster  which  should  then  be  gradually  poured  into  wa- 
ter, being  briskly  stirred  until  the  mixture  is  about  the  consistence 
of  cream,  and  then  it  should  be  thrown  in  rapidly,  as  it  hardens 
quickly.  With  this  injection  we  have  in  one  instance  injected  the 
arteries  of  the  retina  from  the  femoral  artery. — Amer.  Ed.] 

LAENNEC'S   DIVISION   OF   THE   REGIONS    OF    THE   THORAX. 

The  chest  of  a  healthy  person,  when  slightly  struck,  ought  to 
yield  over  its  whole  extent  a  clear  and  distinct  sound.  The  charac- 
ter of  the  sound  derived  from  percussion,  is  different  in  the  different 
parts  of  the  chest ;  on  which  account  it  has  been  divided  by  Lacnnee 
into  fifteen  regions,  twelve  of  which  are  double. 

1.  Subclavian  region.     This  includes  merely  that  portion  of  the 
chest  covered  by  the  clavicle.     When  struck  about  the  middle  or 
sternal  extremity,  this  bone  yields  a  clear  sound,  but  its  humera)  yx- 
tremity  gives  rather  a  dull  sound  :  a  knowledge  of  the  morbid  o     ia- 
tural  sounds  of  the  chest  in  this  region  is  of  great  importanci      for 
from  it  are  usually  derived  the  first  signs  of  the  development     i"  tu- 
bercles in  the  lungs,  which  are  found  in  the  upper  part  of  the  left 
lung,  even  where  they  exist  in  no  other  part  of  the  chest. 

2.  Anterior. superior  region.     This  is  bounded  by  the  clavicle  and 
by  the  fourth  rib  (inclusive)  below.     The  sound,  though  clear,  is  some- 
what less  so  than  over  the  sternal  end  of  the  clavicle. 

3.  Mammary  region.     This  begins  below  the  fourth  rib,  and  termi- 
nates with  the  eighth.     In  the  female,  the  mammary  gland,  in  the 
male,  the  inferior  edge  of  the  pectoralis  major  prevents  this  region 
from  yielding  as  good  a  sound  as  the  anterior-superior  region. 

4.  Submammary  region.      This   extends  from  the  eighth  to  the 
cartilaginous  border  of  the  false  ribs.     On  the  right  side  the  sound 
is  often  dull,  caused  by  the  size  of  the  liver  ;  while  on  the  left,  the 
sound  is  frequently  more  clear  than  natural,  which  is  attributed  to 
the  presence  of  the  stomach  distended  with  gas. 

Sternal  regions,  5.  superior,  6.  middle,  and  7.  inferior.  The  sound 
is  as  clear  over  the  whole  extent  of  the  sternum,  as  on  the  sternal  end 
of  the  clavicle.  However,  the  inferior  region  sometimes  yields  a 
duller  sound,  in  consequence  of  the  accumulation  of  fat  about  the 
neart. 


540  APPENDIX. 

8.  Axillary  region.     This  extends  from  the  axilla  to  the  fourth 
rib  inclusive  ;  the  sound  here  is  naturally  clear. 

9.  Lateral  region.     This  is  bounded  by  the  fourth  rib  above,  and 
terminates  with  the  eighth.     The  sound  is  always  good  on  the  left 
-ide ;   on  the  right  side  it  is  altered  frequently  by  the  liver  rising 
higi.-sr  than  usual,  and  compressing  the  right  lung. 

10.  Inferior  lateral  region.     This  is  bounded  above  by  the  eighth 
rib,  and  terminates  at  the  border  of  the  false  ribs.     This  region  also, 
on  account  of  the  liver,  yields  often  a  completely  dull  sound  on  the 
right  side,  while  ojj  the  contrary  the  left,  for  reasons  before  mention- 
ed, gives  a  clearer  sound  than  natural,  even  where  there  be  effusion 
of  fluid  into  the  pleura,  or  where  the  inferior  portion  of  the  left  lung 
be  obstructed. 

11.  Acromial  region.  This  is  comprehended  between  the  clavicle, 
the  upper  edge  of  the  trapezius,  the  head  of  the  humerus,  and  the 
lower  part  of  the  neck.     The  soft  parts  interposed  in  this  place  pre- 
vent all  sound  from  percussion. 

12.  Upper  scapular  region.     This   corresponds  to  the   supra-spi- 
nous  fossa  of  the  scapula,  and  yields  hardly  any  sound  on  account  of 
the  muscle  which  fills  it.     The  spine  of  the  scapula,  which  forms 
the  inferior  boundary  of  this  region,  sometimes  yields  a  faint  sound 
when  the  arms  are  strongly  compressed  across. 

13.  Lower  scapular  region.     This  corresponds  to  the  infra-spinous 
portion  of  the  scapula.     It  yields  no  sound  on  percussion,  because 
this  portion  of  the  scapula  is  covered  by  the  infra-spinous  muscle. 

14.  Inter-scapular  region.     This  includes  the  space  between  the 
dorsal  edge  of  the  scapula  and  the  spine,  when  the  arms  are  cross- 
ed on  the  breast.     The  muscles  of  this  region  necessarily  render  every 
sound  dull ;  sometimes,  however,  in  thin  persons,  it  gives  a  low  but 
distinct  sound,  if  the  head  be  bent  and  the  arms  crossed  in  order  to 
make  tense  the  trapezius   and  rhornboidei  muscles.     The  spine  in 
this  region  gives  a  good  sound  ;  as  likewise  that  portion  of  the  chest 
included  between  the  superior  dorsal  angle  of  the  scapula  and  the 
first  dorsal  vertebra. 

15.  Inferior  dorsal  region.     This  begins  at  the  level  of  the  inferior 
angle  of  the  scapula,  terminating  at  the   twelfth  dorsal  vertebra. 
Percussion  of  this  region  should  be  made  in  a  transverse  direction,  on 
the  angle  of  the  ribs ;  in  the  upper  part,   the  sound  is  sufficiently 
good  ;  in  the  lower  it  is  slight,  or  often  does  not  exist,  especially  on 
the  right  side,  from  the  presence  of  the  liver  ;  on  the  left  side  it  fre- 
quently gives  an  unnaturally  ''lear  sound,  on  account  of  the  distend. 
ed  state  of  the  stomach. 

OPENING  THE  CRANIUM,  THORAX,  AND  ABDOMEN. 

THE  operation  of  opening  the  cranium  with  the  hammer,  as  de- 
scribed in  a  former  part  of  this  work,  requires  less  labour  and  time 
than  that  done  with  a  saw,  and  ought  always  to  be  preferred,  except 
in  cases  where  there  is  a  wish  to  preserve  the  skull,  or  in  private 
houses,  where  the  feelings  of  the  relatives  arc  likely  to  be  offended 
by  the  noise  made  with  the  hammer.  When  the  saw  is  used,  the 
head  is  to  be  placed  on  a  block,  the  cut  is  to  be  carried  round  in  the 
«ame  direction,  and  the  same  precautions  observed  as  described  in 


APPENDIX.  541 

using  the  hammer :  if  much  caution  be  not  used,  the  saw  is  very 
likely  to  lacerate  the  substance  of  the  brain,  owing  to  the  inequality 
of  thickness  of  the  bone.  In  cases  however  where  the  head  is  to  be 
opened  for  examination  into  the  causes  of  death,  without  an  intention 
of  pursuing  the  dissection  further,  a  different  mode  is  generally  prac- 
tised ;  this  is  done  by  making  an  incision,  by  the  introduction  of  the 
point  of  a  knife  under  the  scalp,  commencing  at  one  ear,  and  carried 
over  the  vertex  to  the  other :  in  this  way  we  avoid  cutting  the  hair, 
which  in  a  female  might  be  troublesome,  and  the  flaps  made  by  the 
dissection  of  the  scalp,  being  reflected  over  the  face  and  neck,  pre- 
vent those  parts  from  being  soiled. 

For  the  purpose  of  examining  the  morbid  appearances  after  death 
in  the  thorax  and  abdomen,  these  cavities  are  generally  opened  at  the 
same  time  ;  an  incision  carried  down  from  the  top  of  the  sternum, 
and  ending  at  the  symphysis  pubis,  dividing  the  integuments,  mus- 
cles, and  peritoneum,  will  bring  the  latter  cavity  into  view ;  next  let 
the  skin  and  muscles  covering  the  front  of  the  thorax  be  turned  back, 
which  will  expose  the  cartilages  connecting  the  ribs  with  the  ster- 
num ;  immediately  at  their  point  of  connexion  with  the  bone,  the  car- 
tilages are  to  be  cut ;  in  doing  this  some  caution  is  to  be  used ;  if  not, 
the  viscera  will  sometimes  be  wounded  by  the  point  of  the  knife  slip- 
ping down  further  than  is  intended  ;  holding  the  knife  horizontally 
between  the  thumb  and  the  middle  finger,  while  the  fore  finger  is 
placed  on  the  back  of  the  instrument  as  a  guide,  will  always  obviate 
this  inconvenience. 

In  some  old  subjects,  where  the  cartilages  of  the  ribs  are  in  some 
degree  ossified,  they  will  not  yield  to  the  knife,  and  here  a  saw  is  to 
be  employed  :  all  the  cartilages,  except  those  of  the  first  ribs  being 
divided,  the  sternum  may  now  be  raised  like  the  lid  of  a  box,  and  a 
verv  convenient  hinge  is  made  by  cutting  the  articulation  of  the  first 
joint  of  the  sternum  on  the  inside,  directly  opposite  the  second  rib  ; 
by  following  this  rule  the  figure  of  the  thorax  will  be  preserved,  after 
the  examination  is  completed,  and  a  view  sufficiently  extensive  for 
common  purposes  be  obtained  of  its  contents.  The  practice  of  ma- 
king a  crucial  incision  for  the  purpose  of  examining  the  contents  of 
the  abdomen,  should  always  be  condemned,  and  should  never  super- 
sede the  longitudinal,  as  a  view  sufficiently  extensive  for  every  pur- 
pose is  obtained  by  the  latter :  while  the  escape  of  fluids,  and  the 
unsightly  appearances  of  the  seams  produced  by  the  former  method, 
are  entirely  prevented. 

The  urinary  and  generative  organs  may  be  removed  from  the  body 
for  examination  through  the  pelvis,  and  if  the  integuments  in  the  pe- 
rinaeum,  and  some  of  the  external  organs  be  left  uninjured,  and  the 
several  outlets  secured,  any  portion  which  is  interesting  as  presenting 
diseased  appearances,  or  which  may  be  required  for  more  accurate 
examination,  may  be  removed  without  the  external  appearance  of 
the  body  being  much  disfigured,  and  without  a  protrusion  of  any  of 
the  remaining  viscera. 


IVERSITY  OF  CALIFORNIA  LIBRARY, 
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